BULLETIN OF THE NEW YORK ACADEMY OF MEDICINE
VOL. 53, No. 8
OCTOBER 1977
DERMATOGLYPHIC ANALYSIS: ANTHROPOLOGICAL AND MEDICAL AS PECTS JOSETTE NAFFAH, M.D. Professor of Genetics Director, Cytogenetic Laboratory French Faculty of Medicine of Beirut Cytogenetic Unit Lebanese National Council for Scientific Research Beirut, Lebanon
T HE study of the human hand has always been fascinating, not only to anthropologists and physicians, but also to psychologists, writers, painters, and chiromancers. One anatomic aspect of the hand-that concerned with the topography of the little epidermal ridges that run parallel to one another on the volar surface of the hand and foot-is of special interest to anthropologists, geneticists, and physicians. The study of palmar prints and finger prints gives much valuable information and is readily accessible. I shall therefore limit this review to the patterns of the hand. The earliest description of epidermal ridges was published at the end of the 17th century, but the study of finger patterns and their use for personal identification was begun by Francis Galton in 1892. The fine details of Address for reprint requests: Josette Naffah, M.D., c/o Georges Ghostin, Air France-Beirut, 1 Square Max Hymans. 75541 Cedex 15, Paris, France.
682
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ridge formation constitute a wholly distinctive set for every individual and remain unchanged throughout life; thus they allow investigation of identity. The most extensive description and classification of dermal patterns were made by Harold Cummins in 1926; he called them "dermatoglyphics." He indicated that in spite of detailed individual differences, large-scale patterns have some regularities found in all persons and can be identified easily. Their statistical study is of great interest from an anthropological point of view since the relative frequencies of different patterns and other characteristics present obvious variations between populations. Further, the study of dermatoglyphics has been recognized in the past few years as a valuable tool in delineating birth defects. EMBRYOLOGY AND GENETICS
The ridge configurations on the volar surface of hands are formed by elevated parallel rows of sweat-gland orifices, each about half a millimeter wide. They develop by the third month of fetal life and are under strong but not exclusive genetic control. Environmental fetal influences are evident if we consider the differences which exist between the left and right hands of a single person and the few dissimilarities in corresponding hands of identical twins. Environmental modifications also can be induced by teratogenic substances. Hereditary influence has been demonstrated by analysis of families using correlation coefficients. Dermatoglyphic features are determined by many genes with an additive action, some of which possibly have dominant inheritance. It seems, for example, that TRC, hypothenar radial loop, the 11nd interdigital loop, and axial triradius have higher heritability indices than other dermatoglyphic characteristics.1,2 Because of their complex polygenic inheritance and because they are not influenced after birth by external factors-geographical, economical, or other-dermatoglyphics are probably the most useful characters for studying the basic relation among different populations. The large number of genes involved account for the frequency of dermatoglyphic abnormalities found in many different syndromes of chromosomal defects. METHODS AND ANATOMICAL CONFIGURATIONS
Dermatoglyphic patterns can be inspected directly, but for quantitative Bull. N.Y. Acad. of Med.
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683
683
DERMATOGLYPHIC
Tented arch
4
\/;\ f
I-st interdigital area
Hypothenar area
rhenari A 3
Fig. 1. Examples of dermatoglyphic patterns. Dotted lines show flexion creases.
data a print must be obtained. Among the various methods available, the most simple are the inkless method outlined by Walker3 or the use of a water-soluble cream ink, applied with a small roller. The patterns are formed by the system of parallel ridges whenever two kinds of complementary singularities occur, namely, the loop and the triradius. As illustrated in Figure 1, a loop is formed when the direction of parallel ridges turns through an angle of 180°. For example, loops are formed on the fingertip by ridges which enter and exit on the same side of the finger and are called radial or ulnar loops according to the side which is concerned. A triradius is the meeting point of three spokes making three angles of approximately 1200 each and delimiting three fields of parallel ridges. On fingertips, a triradius is always found on the radial side of an ulnar loop and vice versa. Two loops opposing each other form a whorl which can be represented by a spiral, concentric rings or ellipses, interlocking loops, or a "pocket" in a loop. There are two triradii associated Vol. 53, No. 8, October 1977
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Loop with 1 ridge count (4 ridges)
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Loop with 0 ridge count
Whorl (double loop) with two ridge counts (3 ridges and 7 ridges)
Arch with 0 ridge count
Fig. 2. Ridge count of different dermatoglyphic patterns.
with a whorl, one on each side of the finger. When no pattern is present, fields of parallel lines are called open fields; if these lines show little curvature, the configuration is termed an arch; there is no triradius on the fingertip if the configuration is an arch, except in the so-called "tented" arch where a triradius is found beneath the "tent" formed by the gently curved lines. On the palm there are usually five triradii: four at the bases of fingers two through five, which are called a, b, c, and d, or digital triradii, and one near the axis of the fourth metacarpal bone, most often at its proximal end near the wrist, called the t or axial triradius (Figure 1). The digital triradii have two radiants enclosing the base of their respective fingers and one proximal radiant from which a line can be traced to its exit at the boundaries of the palm. These lines are called main lines (A, B, C, and D, respectively) and their directions sometimes have anthropological or clinical significance. To indicate the position of the exits of the main lines, the margin of the palm is divided into 13 regions, numbered one through 13. To estimate the main line index (that is, the sum of the two numbers corresponding to the exits of the D and A lines), Cummins4 used another Bull. N.Y. Acad. of Med.
ANALYSIS DERMATOGLYPHIC DERMATOGLYPHI ANALYSIS
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Fig. 3. The measurement of the angle atd serves to specify the position of the axial triradius.
set of numbers, substituting the numbers one to eight for the numbers six to 13. Sometimes there are additional triradii near the main ones, or one of
the usual number is missing. True patterns that are loops or whorls can be found in each of the five areas of the palm: hypothenar, thenar/Ist interdigital, second, third, and fourth interdigital areas (Figure 1). The topographical description of patterns are supplemented by metrical measurements which are used in anthropological and medical investigations. These are numerous; only those in use today will be described here. The total ridge count of the fingers (TRC) is obtained by counting on each finger the number of ridges which would be crossed by a straight line drawn from the triradius to the center or core of the adjacent pattern (Figure 2) and adding up the counts for the 10 fingers. A whorl has two counts; the larger usually is recorded. Vol. 53, No. 8, October 1977
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NAFFAH~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The pattern-intensity index of the fingers (P11) is obtained by counting the total number of triradii on the 10 fingers. The pattern-intensity index of the palm (PIP) is ascertained by counting the number of loops (whorls are considered as two loops) in the five areas of the palm. To specify the position of axial triradius, many methods are available; one of them uses the measurement of the angle atd (see Figure 3) that would be made by straight lines drawn from the axial triradius to the digital triradii a and d; the more distal the triradius t, the wider is angle atd. In adults a proximal axial triradius, which is more frequent, corresponds to an angle atd smaller than 450, a distal axial triradius (called t") to an angle atd larger than 560, and an intermediate axial triradius (called t') to intermediate value of angle atd. Children under 15, especially infants, have a critical value for t" larger than that of adults. Flexion creases, although not dermatoglyphic features, usually are studied with them. On the fingers the absence or fusion of interphalangeal flexion creases constitute peculiarities, while on the palm the replacement of the two transverse creases by a single crease, called the transverse, median, or simian crease, is an unusual configuration. ANTHROPOLOGICAL INVESTIGATIONS
Anthropological variations in dermatoglyphics do not concern only anthropologists and geneticists but also physicians who have to compare peculiarities in a patient with normal control subjects of the same sex and ethnic group. Significant differences exist between the right and the left hands. They are numerous and are usually found to be identical in men and women in all populations. The enumeration of these bilateral differences would be tedious and without interest from a medical point of view, since dermatoglyphic abnormalities in patients are recorded for both hands together. Sexual differences are more important for physicians. The most striking, found in all populations, affect finger-whorl frequency, P11 and TRC, which are higher in men than in women, and finger-arch frequency, which is lower in men than in women. On palms, sexual differences involve mainly the pattern frequencies of the IInd and the 111rd interdigital areas, which are usually higher in men; the frequency of termination of the A line at position 1, which is generally low, but is higher in women; and the frequency of simian creases, which is higher in man. Sexual differences on palms are not identical in all populations; for Bull. N.Y. Acad. of Med.
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example, many Mongoloid populations and the populations which have been investigated in the Middle East, Lebanese and Israeli populations, show an inversion of the usual sexual scheme of pattern frequency on the 111rd interdigital area. In Cyprus there is higher frequency of simian creases in women than in men. Sexual differences are sometimes characteristic of some populations. Thus, the mean value of main line index is higher in men in the Tunisian and Cypriote populations, while the mean value of PIP is higher in women and the frequency of absence of c triradius is higher in men in the Lebanese population. Ethnic origin must be considered, not only because of particular sexual differences, but also because of differences in the average pattern frequencies or metrical values for both sexes. Here again, the most evident differences between populations concern finger patterns. Caucasoid populations have lower whorl frequencies, P11, and TRC, and higher arch frequencies than Mongoloid populations. Negroid populations have finger patterns not unlike Caucasoid ones as a rule, but there are large variations among them according to their geographic origin. Mediterranean populations for which published data are available-from Portugal, Spain, Italy, Algeria, Tunisia, Morocco, Lybia, Israel, Lebanon, and Cyprusshow some common peculiarities that distinguish them among Caucasoids. They have pattern frequencies and other finger indices that are closer to Mongoloid frequencies than those of Northern European populations (see the accompanying table). For palmar pattern frequencies, differences between Caucasoid, Mongoloid, and Negroid populations are not always prominent. In the hypothenar area, pattern frequencies are higher in Caucasoid (30% to 50%) than in Mongoloid (10% to 30%) or Negroid (0-20%) populations. In the thenar/Ist interdigital area, pattern frequencies of Caucasoid populations are low (5% to 20%) and equal to those of Mongoloid populations, except for some American Indians, who have much higher pattern frequencies in this area. Negroid populations have rather high pattern frequencies. In the IInd interdigital area the pattern frequencies (1% to 10%) of Caucasoids are intermediate between those of Mongoloids, which are low, and those of Negroids, which are higher. In the 1Ijrd interdigital area, pattern frequencies are similar in Caucasoids (30% to 60%) and Negroids, but are much lower in Mongoloids. The IVth interdigital area, in which the average pattern frequencies are the highest in all populations, exhibits few ethnic variations. However, Mongoloid and Negroid populations have higher Vol. 53, No. 8, October 1977
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FINGER PATTERN FREQUENCIES, PATTERN-INTENSITY INDEX OF FINGERS (PII), AND TOTAL RIDGE COUNT OF FINGERS (TRC) OF SAMPLES OF MALES IN VARIOUS POPULATIONS Population
England Germany France Hungary Italy Algeria Israel Egypt Lebanon Cyprus India (Bengal) China Amerindian (Comanche) Brazil (Negroes)
W
U
27.4 25.8 31.8 27.2 36.5 36.8 38.1 40.9 41.4 42.0 43.9 50.7 43.3
62.3
48.5
34.4
57.9
U +R
62.4
R
A
P11
TRC
3.2
12.0 11.4 12.5 12.0 13.1 13.3 13.6 13.8 13.8 14.0 14.1 14.9 13.7
145 131 132.3 135.6
1.9
7.1 11.8 6.7 7.4 4.7 3.9 2.2 3.2 2.9 1.8 2.3 1.4 6.3
2.5
5.2
12.9
-
4.7 4.6
56.8 60.8 58.4
3.0 3.3
56.0 56.4 55.9
3.4 4.1 2.2
52.2 52.0 51.7 -
47.8
156.1 140.6 158
W = whorl, U = ulnar loop, U + R = sum of ulnar and radial loop (given where it is the only form of data available), A = arch.
pattern frequencies than Caucasoid populations (35% to 65%). For other palmar dermatoglyphic features, the published data are insufficient for accurate comparison. It seems that the absence of c triradius is much more frequent in Mongoloid populations than in others. More details about ethnic differences can be found elsewhere.5 BIRTH DEFECTS AND DERMATOGLYPHICS
Some peculiarities of dermatoglyphics and flexion creases are found in a variety of clinical syndromes caused by genetic abnormalities or teratogenic drugs. The same dermatoglyphic feature may be associated with more than one clinical entity. Further, any isolated feature, whether rare or common, also may be present in healthy individuals. Hence, dermatoglyphics must be considered together with other clinical signs in attempting to reach a diagnosis. Study of dermatoglyphics helps the physician ascertain whether a disease is congenital or not. Chromosomal abnormalities. Examination of dermal patterns is of particular value in cases of chromosomal aberration. The discovery of dermal peculiarities in Down's syndrome was first pointed out by Cummins. In Down's syndrome (21 trisomy), deviations from normal consist of an increased frequency of ulnar loops on fingers and reduced TRC. Radial Bull. N.Y. Acad. of Med.
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loops are shifted from their usual site of occurrence (i.e., the index) to the third, fourth, or fifth fingers. In the palm the axial triradius is placed distally, the angle atd being wider than 560. Other significant features are the high frequency of the simian crease and a single crease on the fifth finger. Relatives of patients or carriers of balanced translocation 21/D have a wider angle atd than control subjects. In many other syndromes of chromosomal abnormality, dermatoglyphic pecularities are an important part of presumptive diagnosis. The main clinical features of most frequent syndromes are indicated below. In trisomy 18 or Edward's syndrome, apart from the mental retardation which appears in the few babies still surviving a year after birth-which is usual in all autosomal chromosome aberrations-the most common abnormalities are prominent occiput, small receding chin, low uncurled ears, broad, short thorax, short fingers with flexion deformity, and genitourinary and cardiac defects. The characteristic dermal configurations include high frequency of arches on fingers, hypoplasia of ridge development, absence of distal flexion crease on the third through the fifth finger, and presence of a simian crease. In the syndrome of partial deletion of the long arm of chromosome 18-(18q-), facial dysmorphia is, in some respects, the reverse of that in trisomy 18: protruding mandible, midface dysplasia, overcurled helix and prominent anthelix of the ear, carp-shaped mouth, and tapering fingers are the most important symptoms; on the fingers there is an excess of whorls, which is the reciprocal of an excess of arches. When there is deletion of the short arm of chromosome 18(18p-), there is neither characteristic facial dysmorphia nor a special dermatoglyphic pattern; however, hypertelorism, palpebral ptosis, and low-set, large, poorly formed ears usually are found; the axial triradius is sometimes placed distally and TRC is often high. Trisomy of chromosome 13 is associated with a clinical syndrome which partially overlaps that of trisomy 18. However, some features are found more commonly in trisomy 13; these include microphtalmia or anophtalmia, cleft lip and palate, polydactyly, capillary hemangiomata, and localized defects of the scalp. Axial triradius is more distally displaced than in all other chromosomal aberration syndromes, radial loop frequency is increased on fingers, and a thenar/Ist interdigital pattern and simian creases are frequent. The syndrome of deletion of the short arm of chromosome 5(5p-), Vol. 53, No. 8, October 1977
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called cri-du-chat disease, is well delineated. The most striking feature is the cry of the newborn, similar to the mewing of a kitten; this usually persists for a few months. Other common features are hypertelorism, antimongoloid slant of palpebral fissures, micrognathia, short neck, and premature graying of the hair. Simian crease, high frequency of thenar patterns, intermediate axial triradius, and deficiency of ulnar loops on fingers are the usual dermatoglyphic features. Deletion of the short arm of chromosome 4(4p-) is associated with hypertelorism, antimongoloid slant, and micrognathia, but not with.other symptoms of 5p- syndrome. Exophthalmos, palpebral ptosis, short philtrum, precocious puberty, low TRC, and hypoplasia of dermal ridges are among the features distinguishing 4p- from 5p- syndrome. Two syndromes involving autosomal chromosomes have been identified recently through the discovery of numerous cases: partial trisomy and deletion of the short arm of chromosome 9. In some respects the two syndromes may be opposite as type and countertype. In trisomy 9p(9p+) syndrome the most frequent features are brachycephaly with frontal bossing, enophthalmia, and antimongoloid slant of palpebral fissures. In monosomy 9p(9p-) syndrome, we find trigonocephaly with parietal flattening, exophthalmos, and mongoloid slant. Some features are common to the two syndromes, e.g., hypertelorism and prominent anthelix of the ear. Dermatoglyphic peculiarities are of diagnostic value in the 9p+ syndrome only: they include absence of triradius c, simian crease, and excess of
arches on the fingers. Abnormalities involving sex chromosomes produce the most striking effects on finger patterns, expecially on TRC. As a rule, the excess of sex chromosomes reduces the TRC and the lack of sex chromosomes increases the TRC. The X chromosome has approximately twice the effect of the Y chromosome. Thus, patients with Turner's syndrome (XO, mosaicism, structural abnormalities of X in women) have a mean TRC greater than that of normal women (average: 30 ridges more). Patients with excess of X chromosomes, in women (triple X, tetra X) or in men (Klinefelter's syndrome with various chromosomal abnormalities: XXY, XXXY...), would have, respectively, a mean reduced TRC of 30 or 60 ridges in comparison with the TRC of normal women or men. Excess of Y chromosomes in man reduces the TRC by approximately 12 ridges in comparison with normal man. Observed values are in good accordance with these expected values.6 Bull. N.Y. Acad. of Med.
ANALYSIS DERMATOGLYPHIC DERMATOGLYPHIC ANALYSIS
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Dermatoglyphic study is helpful, especially in cases in which there are neither specific abnormalities of growth development nor dysmorphic features as in triple X or tetra X syndrome, in which mental retardation or psychosis are often the only clinical features. Of course, all dermatoglyphic findings must be studied in comparison with those of control subjects of the same population as the patients. Birth defects without patent chromosomal aberrations. In many clinical entities dermatoglyphics which deviate significantly from normal have been reported.7 They include conditions caused by single gene disorders, diseases in which the role of genetic influence is not well defined, and acquired prenatal diseases. In most of these the dermatoglyphic deviations are statistical and not evident in individuals, so they are not of diagnostic value. Two genetic diseases, however, have clearly delineated dermatoglyphic features: the Cornelia de Lange and the Rubinstein-Taybi syndromes. The first includes retardation of growth and of mental development, microbrachycephaly, hypertrichosis, and peculiar facies. The eyebrows meet in the midline, the lashes are very long, there are hypertelorism and antimongoloid slant of palpebral fissures, the nasal bridge is depressed, the nostrils are anteverted, the chin is prominent, the palatal arch is high, the fingers are tapered, the thumb is proximally placed, and sometimes there is lobster-claw-finger deformity. Dermatoglyphics are characterized by decreased whorl frequency and increased radial loop frequency on fingers, presence of thenar pattern, absence of c and b triradii replaced by an intermediate triradius (zygodactylous configuration), distal axial triradius, and simian crease. The genetics of this syndrome are not clearly established yet. The condition is probably due to a single gene disorder with recessive autosomal inheritance; some authors favor a dominant disease with incomplete penetrance, and a polygenic inheritance is not excluded. Some patients have been found to have a chromosomal defect, but the chromosomal aberration is not of any consistent type. The Rubinstein-Taybi syndrome also includes short stature and mental retardation. The facies is characterized by a beaked nose, an antimongoloid slant of the eyes, often a palpebral ptosis, and high eyebrows. The thumbs and great toes are unusually broad. The dermatoglyphic peculiarities are increased arch frequency on fingers, additional triradius on the apex of the thumb near the nail, a radial loop on a finger other than the index, pattern on thenar/Ist and LInd interdigital areas, distal axial triradius, Vol. 53, No. 8, October 1977
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and frequent simian crease. As in the Cornelia de Lange syndrome, the mode of inheritance of the Rubinstein-Taybi syndrome is not clear; it may be polygenic. Some defects caused by environmental teratogens are associated with unusual dermatoglyphics. In some, such as the thalidomide syndrome, the development of limbs is often disturbed; thus, it is not surprising that abnormal dermatoglyphics occur. In prenatal rubella syndrome, limb development is normal. The most common defects are microcephaly, cataract, deafness, blindness, and abnormalities of the cardiovascular or central nervous systems. Dermatoglyphic features include distal axial triradius, high palmar pattern frequency, increased whorl frequency on fingers of affected males, and frequent simian crease. As transitory chromosomal aberrations occur during rubella, dermatoglyphic peculiarities may be the consequence of these chromosomal abnormalities. The systematic study of dermatoglyphics in disorders which are suspected or proved to be caused by genetic abnormalities or by environmental agents which exert their effects early in gestation will lead to the discovery of a wide array of diseases in which dermatoglyphics deviate from normal. The way by which altered genes or an excess or lack of genes induces dermatoglyphic modifications is not yet understood. In order to be able to find a solution for the problem of the development of dermal ridges, we must accumulate data extensively on chromosome aberrations and their corresponding dermatoglyphic features and on the metabolism of gene action. Even now, however, we can consider dermatoglyphics a diagnostic tool which often can be helpful in strengthening a diagnostic impression.
1.
2. 3. 4.
REFERENCES Prints, Palms and Soles. New York, Holt, S. B.: The Genetics of Dermal Dover, 1961. Ridges. Springfield, Ill, Thomas, 5. Naffah, J.: Dermatoglyphics and flex1968. ion creases in Lebanon. Amer. J. Loesh, D.: Genetics of dermatoglyphic Phys. Anthrop. 41:391, 1974. pattern on palm. Ann. Hum. Genet. 6. Penrose, L. S. Finger-print pattern and 34:227, 1971. the sex chromosomes. Lancet 1:299, Walker, N. F.: Inkless methods of 1967. finger, palm and sole printing. J. 7. Alter, M.: Dermatoglyphic analysis as Pediat. 50:27, 1957. a diagnostic tool. Medicine 46:35, Cummins, H. and Midlo, C.: Finger 1967.
Bull. of N.Y. Acad. of Med.
VOL. 53, No. 8
OCTOBER 1977
DERMATOGLYPHIC ANALYSIS: ANTHROPOLOGICAL AND MEDICAL AS PECTS JOSETTE NAFFAH, M.D. Professor of Genetics Director, Cytogenetic Laboratory French Faculty of Medicine of Beirut Cytogenetic Unit Lebanese National Council for Scientific Research Beirut, Lebanon
T HE study of the human hand has always been fascinating, not only to anthropologists and physicians, but also to psychologists, writers, painters, and chiromancers. One anatomic aspect of the hand-that concerned with the topography of the little epidermal ridges that run parallel to one another on the volar surface of the hand and foot-is of special interest to anthropologists, geneticists, and physicians. The study of palmar prints and finger prints gives much valuable information and is readily accessible. I shall therefore limit this review to the patterns of the hand. The earliest description of epidermal ridges was published at the end of the 17th century, but the study of finger patterns and their use for personal identification was begun by Francis Galton in 1892. The fine details of Address for reprint requests: Josette Naffah, M.D., c/o Georges Ghostin, Air France-Beirut, 1 Square Max Hymans. 75541 Cedex 15, Paris, France.
682
J. NAFFAH
682J.
NAFFAH
ridge formation constitute a wholly distinctive set for every individual and remain unchanged throughout life; thus they allow investigation of identity. The most extensive description and classification of dermal patterns were made by Harold Cummins in 1926; he called them "dermatoglyphics." He indicated that in spite of detailed individual differences, large-scale patterns have some regularities found in all persons and can be identified easily. Their statistical study is of great interest from an anthropological point of view since the relative frequencies of different patterns and other characteristics present obvious variations between populations. Further, the study of dermatoglyphics has been recognized in the past few years as a valuable tool in delineating birth defects. EMBRYOLOGY AND GENETICS
The ridge configurations on the volar surface of hands are formed by elevated parallel rows of sweat-gland orifices, each about half a millimeter wide. They develop by the third month of fetal life and are under strong but not exclusive genetic control. Environmental fetal influences are evident if we consider the differences which exist between the left and right hands of a single person and the few dissimilarities in corresponding hands of identical twins. Environmental modifications also can be induced by teratogenic substances. Hereditary influence has been demonstrated by analysis of families using correlation coefficients. Dermatoglyphic features are determined by many genes with an additive action, some of which possibly have dominant inheritance. It seems, for example, that TRC, hypothenar radial loop, the 11nd interdigital loop, and axial triradius have higher heritability indices than other dermatoglyphic characteristics.1,2 Because of their complex polygenic inheritance and because they are not influenced after birth by external factors-geographical, economical, or other-dermatoglyphics are probably the most useful characters for studying the basic relation among different populations. The large number of genes involved account for the frequency of dermatoglyphic abnormalities found in many different syndromes of chromosomal defects. METHODS AND ANATOMICAL CONFIGURATIONS
Dermatoglyphic patterns can be inspected directly, but for quantitative Bull. N.Y. Acad. of Med.
DERMATOGLYPHIC ANALYSIS
683
683
DERMATOGLYPHIC
Tented arch
4
\/;\ f
I-st interdigital area
Hypothenar area
rhenari A 3
Fig. 1. Examples of dermatoglyphic patterns. Dotted lines show flexion creases.
data a print must be obtained. Among the various methods available, the most simple are the inkless method outlined by Walker3 or the use of a water-soluble cream ink, applied with a small roller. The patterns are formed by the system of parallel ridges whenever two kinds of complementary singularities occur, namely, the loop and the triradius. As illustrated in Figure 1, a loop is formed when the direction of parallel ridges turns through an angle of 180°. For example, loops are formed on the fingertip by ridges which enter and exit on the same side of the finger and are called radial or ulnar loops according to the side which is concerned. A triradius is the meeting point of three spokes making three angles of approximately 1200 each and delimiting three fields of parallel ridges. On fingertips, a triradius is always found on the radial side of an ulnar loop and vice versa. Two loops opposing each other form a whorl which can be represented by a spiral, concentric rings or ellipses, interlocking loops, or a "pocket" in a loop. There are two triradii associated Vol. 53, No. 8, October 1977
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Loop with 1 ridge count (4 ridges)
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Loop with 0 ridge count
Whorl (double loop) with two ridge counts (3 ridges and 7 ridges)
Arch with 0 ridge count
Fig. 2. Ridge count of different dermatoglyphic patterns.
with a whorl, one on each side of the finger. When no pattern is present, fields of parallel lines are called open fields; if these lines show little curvature, the configuration is termed an arch; there is no triradius on the fingertip if the configuration is an arch, except in the so-called "tented" arch where a triradius is found beneath the "tent" formed by the gently curved lines. On the palm there are usually five triradii: four at the bases of fingers two through five, which are called a, b, c, and d, or digital triradii, and one near the axis of the fourth metacarpal bone, most often at its proximal end near the wrist, called the t or axial triradius (Figure 1). The digital triradii have two radiants enclosing the base of their respective fingers and one proximal radiant from which a line can be traced to its exit at the boundaries of the palm. These lines are called main lines (A, B, C, and D, respectively) and their directions sometimes have anthropological or clinical significance. To indicate the position of the exits of the main lines, the margin of the palm is divided into 13 regions, numbered one through 13. To estimate the main line index (that is, the sum of the two numbers corresponding to the exits of the D and A lines), Cummins4 used another Bull. N.Y. Acad. of Med.
ANALYSIS DERMATOGLYPHIC DERMATOGLYPHI ANALYSIS
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Fig. 3. The measurement of the angle atd serves to specify the position of the axial triradius.
set of numbers, substituting the numbers one to eight for the numbers six to 13. Sometimes there are additional triradii near the main ones, or one of
the usual number is missing. True patterns that are loops or whorls can be found in each of the five areas of the palm: hypothenar, thenar/Ist interdigital, second, third, and fourth interdigital areas (Figure 1). The topographical description of patterns are supplemented by metrical measurements which are used in anthropological and medical investigations. These are numerous; only those in use today will be described here. The total ridge count of the fingers (TRC) is obtained by counting on each finger the number of ridges which would be crossed by a straight line drawn from the triradius to the center or core of the adjacent pattern (Figure 2) and adding up the counts for the 10 fingers. A whorl has two counts; the larger usually is recorded. Vol. 53, No. 8, October 1977
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J.
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The pattern-intensity index of the fingers (P11) is obtained by counting the total number of triradii on the 10 fingers. The pattern-intensity index of the palm (PIP) is ascertained by counting the number of loops (whorls are considered as two loops) in the five areas of the palm. To specify the position of axial triradius, many methods are available; one of them uses the measurement of the angle atd (see Figure 3) that would be made by straight lines drawn from the axial triradius to the digital triradii a and d; the more distal the triradius t, the wider is angle atd. In adults a proximal axial triradius, which is more frequent, corresponds to an angle atd smaller than 450, a distal axial triradius (called t") to an angle atd larger than 560, and an intermediate axial triradius (called t') to intermediate value of angle atd. Children under 15, especially infants, have a critical value for t" larger than that of adults. Flexion creases, although not dermatoglyphic features, usually are studied with them. On the fingers the absence or fusion of interphalangeal flexion creases constitute peculiarities, while on the palm the replacement of the two transverse creases by a single crease, called the transverse, median, or simian crease, is an unusual configuration. ANTHROPOLOGICAL INVESTIGATIONS
Anthropological variations in dermatoglyphics do not concern only anthropologists and geneticists but also physicians who have to compare peculiarities in a patient with normal control subjects of the same sex and ethnic group. Significant differences exist between the right and the left hands. They are numerous and are usually found to be identical in men and women in all populations. The enumeration of these bilateral differences would be tedious and without interest from a medical point of view, since dermatoglyphic abnormalities in patients are recorded for both hands together. Sexual differences are more important for physicians. The most striking, found in all populations, affect finger-whorl frequency, P11 and TRC, which are higher in men than in women, and finger-arch frequency, which is lower in men than in women. On palms, sexual differences involve mainly the pattern frequencies of the IInd and the 111rd interdigital areas, which are usually higher in men; the frequency of termination of the A line at position 1, which is generally low, but is higher in women; and the frequency of simian creases, which is higher in man. Sexual differences on palms are not identical in all populations; for Bull. N.Y. Acad. of Med.
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example, many Mongoloid populations and the populations which have been investigated in the Middle East, Lebanese and Israeli populations, show an inversion of the usual sexual scheme of pattern frequency on the 111rd interdigital area. In Cyprus there is higher frequency of simian creases in women than in men. Sexual differences are sometimes characteristic of some populations. Thus, the mean value of main line index is higher in men in the Tunisian and Cypriote populations, while the mean value of PIP is higher in women and the frequency of absence of c triradius is higher in men in the Lebanese population. Ethnic origin must be considered, not only because of particular sexual differences, but also because of differences in the average pattern frequencies or metrical values for both sexes. Here again, the most evident differences between populations concern finger patterns. Caucasoid populations have lower whorl frequencies, P11, and TRC, and higher arch frequencies than Mongoloid populations. Negroid populations have finger patterns not unlike Caucasoid ones as a rule, but there are large variations among them according to their geographic origin. Mediterranean populations for which published data are available-from Portugal, Spain, Italy, Algeria, Tunisia, Morocco, Lybia, Israel, Lebanon, and Cyprusshow some common peculiarities that distinguish them among Caucasoids. They have pattern frequencies and other finger indices that are closer to Mongoloid frequencies than those of Northern European populations (see the accompanying table). For palmar pattern frequencies, differences between Caucasoid, Mongoloid, and Negroid populations are not always prominent. In the hypothenar area, pattern frequencies are higher in Caucasoid (30% to 50%) than in Mongoloid (10% to 30%) or Negroid (0-20%) populations. In the thenar/Ist interdigital area, pattern frequencies of Caucasoid populations are low (5% to 20%) and equal to those of Mongoloid populations, except for some American Indians, who have much higher pattern frequencies in this area. Negroid populations have rather high pattern frequencies. In the IInd interdigital area the pattern frequencies (1% to 10%) of Caucasoids are intermediate between those of Mongoloids, which are low, and those of Negroids, which are higher. In the 1Ijrd interdigital area, pattern frequencies are similar in Caucasoids (30% to 60%) and Negroids, but are much lower in Mongoloids. The IVth interdigital area, in which the average pattern frequencies are the highest in all populations, exhibits few ethnic variations. However, Mongoloid and Negroid populations have higher Vol. 53, No. 8, October 1977
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FINGER PATTERN FREQUENCIES, PATTERN-INTENSITY INDEX OF FINGERS (PII), AND TOTAL RIDGE COUNT OF FINGERS (TRC) OF SAMPLES OF MALES IN VARIOUS POPULATIONS Population
England Germany France Hungary Italy Algeria Israel Egypt Lebanon Cyprus India (Bengal) China Amerindian (Comanche) Brazil (Negroes)
W
U
27.4 25.8 31.8 27.2 36.5 36.8 38.1 40.9 41.4 42.0 43.9 50.7 43.3
62.3
48.5
34.4
57.9
U +R
62.4
R
A
P11
TRC
3.2
12.0 11.4 12.5 12.0 13.1 13.3 13.6 13.8 13.8 14.0 14.1 14.9 13.7
145 131 132.3 135.6
1.9
7.1 11.8 6.7 7.4 4.7 3.9 2.2 3.2 2.9 1.8 2.3 1.4 6.3
2.5
5.2
12.9
-
4.7 4.6
56.8 60.8 58.4
3.0 3.3
56.0 56.4 55.9
3.4 4.1 2.2
52.2 52.0 51.7 -
47.8
156.1 140.6 158
W = whorl, U = ulnar loop, U + R = sum of ulnar and radial loop (given where it is the only form of data available), A = arch.
pattern frequencies than Caucasoid populations (35% to 65%). For other palmar dermatoglyphic features, the published data are insufficient for accurate comparison. It seems that the absence of c triradius is much more frequent in Mongoloid populations than in others. More details about ethnic differences can be found elsewhere.5 BIRTH DEFECTS AND DERMATOGLYPHICS
Some peculiarities of dermatoglyphics and flexion creases are found in a variety of clinical syndromes caused by genetic abnormalities or teratogenic drugs. The same dermatoglyphic feature may be associated with more than one clinical entity. Further, any isolated feature, whether rare or common, also may be present in healthy individuals. Hence, dermatoglyphics must be considered together with other clinical signs in attempting to reach a diagnosis. Study of dermatoglyphics helps the physician ascertain whether a disease is congenital or not. Chromosomal abnormalities. Examination of dermal patterns is of particular value in cases of chromosomal aberration. The discovery of dermal peculiarities in Down's syndrome was first pointed out by Cummins. In Down's syndrome (21 trisomy), deviations from normal consist of an increased frequency of ulnar loops on fingers and reduced TRC. Radial Bull. N.Y. Acad. of Med.
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loops are shifted from their usual site of occurrence (i.e., the index) to the third, fourth, or fifth fingers. In the palm the axial triradius is placed distally, the angle atd being wider than 560. Other significant features are the high frequency of the simian crease and a single crease on the fifth finger. Relatives of patients or carriers of balanced translocation 21/D have a wider angle atd than control subjects. In many other syndromes of chromosomal abnormality, dermatoglyphic pecularities are an important part of presumptive diagnosis. The main clinical features of most frequent syndromes are indicated below. In trisomy 18 or Edward's syndrome, apart from the mental retardation which appears in the few babies still surviving a year after birth-which is usual in all autosomal chromosome aberrations-the most common abnormalities are prominent occiput, small receding chin, low uncurled ears, broad, short thorax, short fingers with flexion deformity, and genitourinary and cardiac defects. The characteristic dermal configurations include high frequency of arches on fingers, hypoplasia of ridge development, absence of distal flexion crease on the third through the fifth finger, and presence of a simian crease. In the syndrome of partial deletion of the long arm of chromosome 18-(18q-), facial dysmorphia is, in some respects, the reverse of that in trisomy 18: protruding mandible, midface dysplasia, overcurled helix and prominent anthelix of the ear, carp-shaped mouth, and tapering fingers are the most important symptoms; on the fingers there is an excess of whorls, which is the reciprocal of an excess of arches. When there is deletion of the short arm of chromosome 18(18p-), there is neither characteristic facial dysmorphia nor a special dermatoglyphic pattern; however, hypertelorism, palpebral ptosis, and low-set, large, poorly formed ears usually are found; the axial triradius is sometimes placed distally and TRC is often high. Trisomy of chromosome 13 is associated with a clinical syndrome which partially overlaps that of trisomy 18. However, some features are found more commonly in trisomy 13; these include microphtalmia or anophtalmia, cleft lip and palate, polydactyly, capillary hemangiomata, and localized defects of the scalp. Axial triradius is more distally displaced than in all other chromosomal aberration syndromes, radial loop frequency is increased on fingers, and a thenar/Ist interdigital pattern and simian creases are frequent. The syndrome of deletion of the short arm of chromosome 5(5p-), Vol. 53, No. 8, October 1977
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called cri-du-chat disease, is well delineated. The most striking feature is the cry of the newborn, similar to the mewing of a kitten; this usually persists for a few months. Other common features are hypertelorism, antimongoloid slant of palpebral fissures, micrognathia, short neck, and premature graying of the hair. Simian crease, high frequency of thenar patterns, intermediate axial triradius, and deficiency of ulnar loops on fingers are the usual dermatoglyphic features. Deletion of the short arm of chromosome 4(4p-) is associated with hypertelorism, antimongoloid slant, and micrognathia, but not with.other symptoms of 5p- syndrome. Exophthalmos, palpebral ptosis, short philtrum, precocious puberty, low TRC, and hypoplasia of dermal ridges are among the features distinguishing 4p- from 5p- syndrome. Two syndromes involving autosomal chromosomes have been identified recently through the discovery of numerous cases: partial trisomy and deletion of the short arm of chromosome 9. In some respects the two syndromes may be opposite as type and countertype. In trisomy 9p(9p+) syndrome the most frequent features are brachycephaly with frontal bossing, enophthalmia, and antimongoloid slant of palpebral fissures. In monosomy 9p(9p-) syndrome, we find trigonocephaly with parietal flattening, exophthalmos, and mongoloid slant. Some features are common to the two syndromes, e.g., hypertelorism and prominent anthelix of the ear. Dermatoglyphic peculiarities are of diagnostic value in the 9p+ syndrome only: they include absence of triradius c, simian crease, and excess of
arches on the fingers. Abnormalities involving sex chromosomes produce the most striking effects on finger patterns, expecially on TRC. As a rule, the excess of sex chromosomes reduces the TRC and the lack of sex chromosomes increases the TRC. The X chromosome has approximately twice the effect of the Y chromosome. Thus, patients with Turner's syndrome (XO, mosaicism, structural abnormalities of X in women) have a mean TRC greater than that of normal women (average: 30 ridges more). Patients with excess of X chromosomes, in women (triple X, tetra X) or in men (Klinefelter's syndrome with various chromosomal abnormalities: XXY, XXXY...), would have, respectively, a mean reduced TRC of 30 or 60 ridges in comparison with the TRC of normal women or men. Excess of Y chromosomes in man reduces the TRC by approximately 12 ridges in comparison with normal man. Observed values are in good accordance with these expected values.6 Bull. N.Y. Acad. of Med.
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Dermatoglyphic study is helpful, especially in cases in which there are neither specific abnormalities of growth development nor dysmorphic features as in triple X or tetra X syndrome, in which mental retardation or psychosis are often the only clinical features. Of course, all dermatoglyphic findings must be studied in comparison with those of control subjects of the same population as the patients. Birth defects without patent chromosomal aberrations. In many clinical entities dermatoglyphics which deviate significantly from normal have been reported.7 They include conditions caused by single gene disorders, diseases in which the role of genetic influence is not well defined, and acquired prenatal diseases. In most of these the dermatoglyphic deviations are statistical and not evident in individuals, so they are not of diagnostic value. Two genetic diseases, however, have clearly delineated dermatoglyphic features: the Cornelia de Lange and the Rubinstein-Taybi syndromes. The first includes retardation of growth and of mental development, microbrachycephaly, hypertrichosis, and peculiar facies. The eyebrows meet in the midline, the lashes are very long, there are hypertelorism and antimongoloid slant of palpebral fissures, the nasal bridge is depressed, the nostrils are anteverted, the chin is prominent, the palatal arch is high, the fingers are tapered, the thumb is proximally placed, and sometimes there is lobster-claw-finger deformity. Dermatoglyphics are characterized by decreased whorl frequency and increased radial loop frequency on fingers, presence of thenar pattern, absence of c and b triradii replaced by an intermediate triradius (zygodactylous configuration), distal axial triradius, and simian crease. The genetics of this syndrome are not clearly established yet. The condition is probably due to a single gene disorder with recessive autosomal inheritance; some authors favor a dominant disease with incomplete penetrance, and a polygenic inheritance is not excluded. Some patients have been found to have a chromosomal defect, but the chromosomal aberration is not of any consistent type. The Rubinstein-Taybi syndrome also includes short stature and mental retardation. The facies is characterized by a beaked nose, an antimongoloid slant of the eyes, often a palpebral ptosis, and high eyebrows. The thumbs and great toes are unusually broad. The dermatoglyphic peculiarities are increased arch frequency on fingers, additional triradius on the apex of the thumb near the nail, a radial loop on a finger other than the index, pattern on thenar/Ist and LInd interdigital areas, distal axial triradius, Vol. 53, No. 8, October 1977
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and frequent simian crease. As in the Cornelia de Lange syndrome, the mode of inheritance of the Rubinstein-Taybi syndrome is not clear; it may be polygenic. Some defects caused by environmental teratogens are associated with unusual dermatoglyphics. In some, such as the thalidomide syndrome, the development of limbs is often disturbed; thus, it is not surprising that abnormal dermatoglyphics occur. In prenatal rubella syndrome, limb development is normal. The most common defects are microcephaly, cataract, deafness, blindness, and abnormalities of the cardiovascular or central nervous systems. Dermatoglyphic features include distal axial triradius, high palmar pattern frequency, increased whorl frequency on fingers of affected males, and frequent simian crease. As transitory chromosomal aberrations occur during rubella, dermatoglyphic peculiarities may be the consequence of these chromosomal abnormalities. The systematic study of dermatoglyphics in disorders which are suspected or proved to be caused by genetic abnormalities or by environmental agents which exert their effects early in gestation will lead to the discovery of a wide array of diseases in which dermatoglyphics deviate from normal. The way by which altered genes or an excess or lack of genes induces dermatoglyphic modifications is not yet understood. In order to be able to find a solution for the problem of the development of dermal ridges, we must accumulate data extensively on chromosome aberrations and their corresponding dermatoglyphic features and on the metabolism of gene action. Even now, however, we can consider dermatoglyphics a diagnostic tool which often can be helpful in strengthening a diagnostic impression.
1.
2. 3. 4.
REFERENCES Prints, Palms and Soles. New York, Holt, S. B.: The Genetics of Dermal Dover, 1961. Ridges. Springfield, Ill, Thomas, 5. Naffah, J.: Dermatoglyphics and flex1968. ion creases in Lebanon. Amer. J. Loesh, D.: Genetics of dermatoglyphic Phys. Anthrop. 41:391, 1974. pattern on palm. Ann. Hum. Genet. 6. Penrose, L. S. Finger-print pattern and 34:227, 1971. the sex chromosomes. Lancet 1:299, Walker, N. F.: Inkless methods of 1967. finger, palm and sole printing. J. 7. Alter, M.: Dermatoglyphic analysis as Pediat. 50:27, 1957. a diagnostic tool. Medicine 46:35, Cummins, H. and Midlo, C.: Finger 1967.
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