American J o u r n a l of Medical Genetics 38:58-64 (1991)
Diagnosis of Angelman Syndrome in Infants Julie Shapiro Fryburg, W. Roy Breg, and Valerie Lindgren Department of H u m u n Genetics, Yale University School of Medicine, New Haven, Connecticut The diagnosis of Angelman syndrome (AS) has seldom been made in infants because the previously described characteristic manifestations usually are not apparent until after age 2 years. We describe 4 AS patients, one of whom has oculocutaneous albinism, who were < 2 years old when first evaluated. All 4 have deletions of the region q11.2-q13of chromosome 15. In the 3 cases in which parents were available for study the deleted chromosome 15 was maternally derived, as determined by cytological markers. All of the patients presented with severe to profound global developmental delay and postnatal-onset microcephaly; they had seizures, hypotonia, hyperreflexia, and hyperkinesis. All were hypopigmented as compared to their relatives. Each had eye abnormalities; all had choroidal pigment hypoplasia. None were initially described as having an abnormal appearance. We believe that AS is far more common than previously thought and present these 4 children to emphasize the manifestations that may be helpful in making the diagnosis in the young patient. We alsa emphasize the hypopigmentation that patients with AS frequently have, including what we think is the first reported case of albinism and AS. KEY WORDS: chromosome 15 deletion, developmental delay, microcephaly, hypopigmentation, oculocutaneous albinism
teristic “puppet-like” gait and other movements [Angelman, 1965; Williams and Frias, 1982; Willems et al., 19871.So far approximately 70 patients with Angelman syndrome (AS) have been reported. Nearly all were diagnosed after age 2 years when the characteristic manifestations of the syndrome become more obvious. Recently we identified 3 patients with AS who were less than 2 years old and one patient, now 7% years old, who was an infant when first evaluated. Initially the diagnosis became apparent in 3 of these 4 patients when cytogenetic analysis detected deletions of the region q11.2-q13 of chromosome 15. Deletions of this region have been reported in about 60 percent of patients with AS [Imaizumi et al., 1990; Pembrey et al., 19891; the same deletion is also present in about the same proportion of patients with Prader-Willi syndrome (PWS) [Nicholls, et al., 19891. The diagnosis of AS was suspected in one of our 4 patients purely on clinical grounds, suggesting that it should be possible to delineate the characteristics of AS in infants and young children. We describe these 4 children with emphasis on the traits which may be helpful in making an early diagnosis, whether or not the deletion is present. One of these patients appears to be the first recognized patient to have documented AS and oculocutaneous albinism. In all 3 of our cases in which parents were available for study, the deleted chromosome 15 was maternally derived, as determined by cytologic markers. The maternal origin of the deleted chromosome 15 in our cases is consistent with the observation [Knoll et al., 19891that the deletions in AS are of the maternal chromosome 15 while the deletions in PWS are of the paternal chromosome 15.
CLINICAL REPORTS All 4 patients were referred to our genetics clinic by pediatric neurologists for evaluation of microcephaly INTRODUCTION and developmental delay. At the time of referral the In 1965 Angelman described 3 unrelated children patients ranged in age from 5% to 20 months. In each with mental retardation, microcephaly, paroxysms of case pregnancy histories, as well as maternal and paterlaughter, and seizure disorders. In addition they had eye nal perinatal exposures, were apparently normal. Famabnormalities, prominent jaw, large mouth, tongue pro- ily histories were unremarkable for mental retardation trusion, widely spaced teeth, absent speech, and charac- and microcephaly. An 8-year-old brother of patient 4 is dyslexic and a 6-year-oldbrother of patient 1,as well as the patient’s father and paternal grandfather, has atReceived for publication January 26,1990; revision May 9,1990. tention deficit disorder. The major common characteristics of these 4 patients Address reprint requests to Julie S. Fryburg, Yale University School of Medicine, 333 Cedar St., P.O. Box 3333, New Haven, CT can be grouped as follows: neurological, pigmentary, 06510. ophthalmic, and craniofacial (Table I). ~~
0 1991 Wiley-Liss, Inc.
Angelman Syndrome TABLE I. Clinical Findings in AS Patients
Neu r o1ogica1 Hypotonia Hyperreflexia Hyperkinesisipuppet-like movements Ataxiaidysmetria Developmental delayimental retardation Absentiminimal speech Microcephaly Inappropriate laughter Seizures Abnormal EEG Excessive drooling Tongue thrusting Opthalmic Choroidal pigment hypoplasia Strabismus Nystagmus Pigmentary Blue eyes Blond hair Oculocutaneous albinism Craniofacial Flat occiputihorizontal occipital groove Thin upper lipiwide mouth Prominent jawipointed chin Widely spaced teeth Cytogenetic 15q11.2-ql3 deletion Maternal derivation of deletion
1
Patienta 2 3
+ + + + + + + + + + + ++ +
+ + + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + + + +
+ + + + + + +
+ + + + +
+ + + +
NA
+ + -
+ + -
+ + + + + + -
"NA= not available for study
Neurological Manifestations The neurological manifestations of these patients include microcephaly, developmental delay, seizure disorders, and neuromuscular abnormalities. Each patient had birth weight, length, and head circumference (OFC) a t the 50th centile, but by age 6 months the OFC was not increasing consistently with other somatic growth. This trend is exemplified by patient 1(Fig. 11whose OFC was a t the 50th centile a t birth, at the 25th centile by age 3 months, a t the 10th centile by 7 months, and a t the 5th centile by 12 months. Since age 15 months her OFC has been well below the 3rd centile. Similar patterns are shown for the other 3 patients. All of the patients have severe to profound global developmental delay with minimal or absent speech, but no loss of any skills previously attained. Developmental assessments in all patients at 18 to 20 months placed their development a t a 7 to 8 month level. By 24 months only one patient was beginning to cruise. Although all of the patients are noted to have frequent vocalizations, only the 7I/z-year old patient has one word, mama, which she has had since about 3% years. By 10 months the patients had developed seizures of varying types, including absence seizures in one patient, myoclonic seizures in 2 patients, and tonic-clonic seizures in one patient. All of the patients had abnormal electroencephalograms characterized by multiple generalized bursts of irregular, high-voltage, 2-3 cps activity intermixed with spike and sharp wave activity. These findings are compatible with the patterns reported in other patients with AS [Bower and Jeavons, 1967; Moore and Jeavons, 1972; Kibel and Burness, 1973; Mayo e t al., 1973; Boyd et al., 19881. In 2 of the 4 patients seizures were very difficult to control. One of
56 I52
I
97% 50% 3%
48
Head 44 Circumference (ems) 40 36 32 I
t
28 I 0
I
I
4
I
I
8
I
I
12
59
I
I
16
I
I
20
I
I
24
I
I
1
28
Age (months) Fig. 1. Head circumferencesofpatients.Patient 1(small dashes),patient 2 (longdashes), patient 3 (solid light line), patient 4 (solid dark line).
60
Fryburg et al.
these patients, who is now T1/2 years old, has been clinically seizure-free since 3 years. This is consistent with the observation that patients with AS have more florid EEG changes and seizures recalcitrant to therapy in infancy and early childhood, but the seizures may ameliorate with advancing age [Boyd et al., 19881. While CT scans of the head were normal in 2 patients, magnetic resonance imaging demonstrated partial agenesis of the corpus callosum in the third patient and non-specific periventricular white matter loss in the fourth. Other evaluations for these neurologic abnormalities included routine cytogenetic analysis, thyroid function tests, blood chemistries, amino acids, lactate, pyruvate, urine genetic screen and organic acids, cerebral spinal fluid chemistries, and lysosomal enzyme assays, all of which were normal. By age 6 months all of the patients were described as hypotonic with brisk deep tendon reflexes. Also present since age 6 months have been occasional problems with swallowing and choking, which have been reported in other patients with AS [Moore and Jeavons, 19721. Excessive drooling and tongue thrusting were present a t 6 months and have become more pronounced and exaggerated over time. By 10 months all of the patients were noted to have frequent, jerky, erratic movements which made them appear hyperkinetic. All have histories of paroxysms of laughter by age 12 months. Two of the Datients (patients 2 and 3) have had dvsmetria on reaching for objects since age 10 and 12 months, respectively. The 71h-year-old has the characteristic ataxia with jerky movements of her arms and flapping of her hands commonly seen in older patients with AS.
Fig. 2. Patient 2 at age 24 months, seated with his mother, is hypoto the mother, pigmented as
Pigmentary Features All 4 our patients have blue eyes and have lighter hair and fairer skin than their relatives. Figures 2 and 3 demonstrate this contrast in coloring. The most striking example of this hypopigmentation is seen in patient 3 who has oculocutaneous albinism (OA). She is shown in Figure 4 at age 4 months when the diagnosis of OA was made on the basis of her fair skin with white hair and ophthalmologic examination which showed nystagmus, blond fundus, and transillumination of the iris. The diagnosis was confirmed by low hairbulb tyrosinase activity and characteristic hairbulb EM studies. The patient is photophobic and wears darkened glasses when exposed to the sun. Ophthalmic Manifestations All of the patients have ocular abnormalities. All 4 have choroidal pigment hypoplasia. One patient has strabismus and one has nystagmus; a 3rd patient has strabismus and nystagmus. The patient with albinism, as described above, has nystagmus, transillumination, and macular hypoplasia. The other 3 patients do not have iris transillumination and have foveal reflexes. Craniofacial Abnormalities All 4 patients were described a s having a normal facial appearance at 6 to 12 months. All had flat occiputs and 3 had horizontal occipital grooves. All smiled fre-
Fig. 3. Patient 1 a t age 26 months, shown with her brothers, is hypopigmented as compared to them (and parents, not shown here).
Angelman Syndrome quently and the smiling was often described as unprovoked, inappropriate, and prolonged. In 3 of the 4 patients the teeth were widely spaced. With advancing age certain facial changes typical of AS, such as the wide mouth with thin upper lip, prominent jaw, and pointed chin, appear more obvious (Figs. 4-6) [Robb et al., 19891.
CYTOGENETIC FINDINGS Chromosomes from each of the 4 patients were examined by using methotrexate synchronization and thymidine release to obtain cells with 550 or more bands. Three of the 4 cases each had a deletion of band q12 of one chromosome 15 and a portion of the flanking bands q11.2 and 913; the deletion in patient 2 may be slightly smaller and include only q11.2 and most of q12 (Fig. 7).
61
Patient 3 with albinism is adopted and her biologic parents were unavailable for study. However, the parents of the other 3 patients have normal chromosomes; thus, all 3 deletions are de novo. A study of the chromosome 15 heteromorphisms was performed on the 3 available families. In each case the deleted chromosome was maternally derived. Figure 8 illustrates the analysis of patient 2.
DISCUSSION We have described 4 children with AS to emphasize certain characteristics t h a t may be helpful in the early recognition of other young patients with AS. Manifestations of AS, especially of the face, appear to evolve over time [Baraitser et al., 1987; Robb et al., 19891. We do not yet know how early the diagnosis can be made on clinical
Fig. 4. Patient 3 with oculocutaneous albinism a t age 4 months (left),with no obvious anomalies; age 7% years (right),with the typical facial appearance of AS.
Fig. 5. Patient 1 at 20 months of age (left) and 26 months (right),demonstrating some of the subtle findings in AS, including wide mouth with thin upper lip, pointed chin, prominent jaw, and constant smiling and drooling.
62
Fryburg et al.
Fig. 6. Patient 4 a t age 12 months (left), 16 months (center), 24 months (right), illustrating t h e evolution of a patient with AS. Only very mild abnormality is present a t age 12 months. By 16 months changes i n her mouth, lips, and jaw a r e prominent. By 24 months these findings have become even more evident.
15
dell151
Fig. 7. Chromosome 15 deletions. The ideograms (center) show chromosomes 15 with an arrow pointing to band q12 in the normal chromosome (left). This band, as well as portions of the flanking bands q11.2 and q13, are absent from the deleted chromosome 15 (right), except in patient 2 where the deletion appears to be a bit smaller and to include only q11.2 and most of q12. Two pairs of chromosomes 15 from each patient are displayed with the normal chromosome on left and an arrow pointing to band q12. The deleted chromosome 15 is on right of each pair. Patient 1 (lower left), patient 2 (upper left), patient 3 (lower right), patient 4 (lower right).
grounds, but study of our patients indicates that the following features are probably present by age 6-12 months; post-natal onset microcephaly, developmental delay, seizure disorder, frequent hyperkinetic, movements of the trunk and limbs often with hypotonia and hyperreflexia, hypopigmentation, flat occiput, choroidal pigment hypoplasia, and paroxysms of laughter. The hyperkinesis and hypopigmentation appear to be quite characteristic of AS. Recognition of these features should lead to a highresolution chromosome study focused on chromosome 15, thus possibly avoiding unnecessary, expensive, and invasive investigations. Analysis of chromosomes of routine length in 3 of these 4 cases failed to show the deletion, which emphasizes the need to examine the chromosomes with high-resolution banding. In fact, the
deletion was missed in one patient even on high-resolution chromosomes when a nonfocused study was performed; however, when the chromosomes were reexamined in light of the clinical findings, the deletion was evident. It should be emphasized that detection of the deletion was invaluable in making the diagnosis of AS in these patients. If the deletions had not been found, we would have been reluctant to make the diagnosis. Since only about 60% of AS patients have a microscopically detectable deletion [Imaizumi et al., 1990; Pembrey et al., 19891, those infants with AS without a deletion will continue to be a diagnostic challenge. Ophthalmologic examination can detect choroidal pigment hypoplasia and other eye abnormalities [Massey and Roy, 19731, if present. An EEG may show characteristic changes, even in the absence of seizures [Boyd e t al., 19881.Presence of
Angelman Syndrome
63
nism, in PW6 [Hittner and King, 1982; Wiesner et al., 1987; Phelan et al., 1988; Butler, 1989; Wallis and Beighton, 19891 and in AS supports the notion that a geneb) on chromosome 15 is involved in pigment formation and deletion of this region results in varying degrees of hypopigmentation. Each of our patients has a deletion and hypopigmentation. However, there are cases of hypopigmented AS and PWS patients with normal chromosomes, a s well as normally pigmented AS and PWS patients who have the deletion [Pembrey et al., 1989; Williams et al., 19891. The exact mechanism of involvement of genes in this region in pigment production is not yet known. That hypopigmentation is common in both PWS and AS suggests that the postulated pigmentation gene is not involved in a n imprinting process. Further studies are needed to clarify these issues. Fig. 8. Patient 2 (bottom pair of chromosomes) inherited a normal chromosome 15 (left) with double satellites from his father (F). The abnormal chromosome 15 (right)is derived from a maternal (M) chromosome 15 with a large p11.2 region.
the common manifestations noted above, especially the hypopigmentation and hyperkinesis in a patient without a deletion, may make the diagnosis on clinical grounds alone. We think that AS is far more common than previously thought, as indicated by our identification of these 4 patients within a year’s span, as well as the increasing number of reports of AS [Magenis et al., 1987; Dorries et al., 1988; Robb et al., 19891. With recognition of the changes that we think are characteristic in infants, perhaps earlier diagnosis will be possible. The same deletion has been found in patients with PWS and in a few reported cases that did not, a t least initially, appear to have either PWS or AS [Schwartz et al., 19851. Thus far the deletions seem to be similar cytogenetically and molecularly [Donlon, 19881, yet they result in very different clinical syndromes [Magenis et al., 19871. Increasingly, it appears that deletions of a paternal chromosome 15 result in PWS while deletions of a maternal chromosome 15 result in AS [Knoll et al., 19891. The maternal origin of the deletion in AS, as opposed to the paternal origin in PWS, is substantiated in our patients. These findings have led to the hypothesis that this region of the genome is imprinted in some fashion (perhaps by methylation) such that maternal and paternal copies are not equivalent in development [Searle et al., 19891. Nicholls e t al., [1989] have recently demonstrated uniparental heterodisomy, i.e., inheritance of 2 different maternal chromosomes 15 and no paternal copy of chromosome 15, in several cases of PWS without deletions. It will be interesting to see if any of the patients who meet the clinical criteria for AS but have no detectable deletion will show uniparental disomy of paternal origin. Our patient with AS and OA strengthens the association of hypopigmentation with AS and this deletion. The presence of hypopigmentation, and in some cases albi-
ACKNOWLEDGMENTS We thank the patients’ family members for their cooperation, Drs. David Whiteman and Murray Engel for patient referrals, Drs. Laura Ment and Larry Wicker for their EEG interpretations, and Dr. Richard King for this involvement with ongoing pigment studies. REFERENCES Angelman H (1965):“Puppet” children: A report on three cases. Dev Med Child Neurol 7:681-683. Baraitser M, Patton M, Lam ST, Brett EM, Wilson J (1987):The Angelman (happy puppet) syndrome: is i t autosomal recessive? Clin Genet 31:323-330. Bower BD, Jeavons PM (1967):The “happy puppet” syndrome. Arch Dis syndrome. Arch Dis Child 42:298-302. Boyd SG, Harden A, Patton MA (1988):The EEG in early diagnosis of the Angelman (happy puppet) syndrome. E u r J Pediatr
147508-513. Butler MG (1989):Hypopigmentation: A common feature of PraderLabhart-Willi syndrome. Am J Hum Genet 45:140-146. Donlon TA (1988):Similar molecular deletions on chromosome 15q11.2 are encountered in both the Prader-Willi and Angelman syndromes. Hum Genet 80:322-328. Dorries A, Spohr HL, Kunze J (1988):Angelman (“happy puppet”) syndrome-seven new cases documented by cerebral computed tomography: review of the literature. Eur J Pediatr 148:270-273. Hittner HM, King RA (1982):Oculocutaneous albinoidism as a manifestation of reduced neural crest derivatives in the Prader-Willi syndrome. Am J Ophthalmol 94:328-337. Imaizumi K, Takada F, Kuroli Y, Naritomi K, Hamabe J, Nikawa N (1990):Cytogenetic and molecular study of Angelman syndrome. Am J Med Genet 35:314-318. Kibel MA, Burness FR (1973):“The happy puppet” syndrome. Cent Afr J Med 19:91-93. Knoll J H , Nicholls RD, Magenis RE,Graham J M , Lalande M, Latt SA (1989):Angelman and Prader-Willi syndromes share a common chromosome 15 deletion but differ in parental origin of the deletion. Am J Med Genet 32:285-290. Magenis RE,Brown MG, Lacy DA, Budden S, LaFranchi S (1987):Is Angelman syndrome a n alternate result of del(15)(qllq13)?Am J Med Genet 28:829-838. Massey JY, b y F H (1983):Ocular manifestations of the happy puppet syndrome. J Pediatr Ophthalmol 10:282-284. Mayo 0,Nelson MM, Townsend HR(1973):Three more ‘happy puppets’. Dev Med Child Neurol 1563-73. Moore JR, Jeavons PM (1973):The “happy puppet” syndrome: two cases and a review of five previous cases. Neuropadiatrie 4:172-179. Nicholls RD, Knoll J H , Butler MG, Karam S, Lalande M (1989):Ge-
64
Fryburg et al.
netic imprinting suggested by maternal heterodisomy in non-deletion Prader-Willi syndrome. Nature 342:281-285. Pembrey M, Fennel SJ, Van Den Berghe JV, Fitchett M, Summers D, Butler L, Clarke C, Griffiths M, Thompson E, Super M, Baraitser M (1989): The association of Angelman’s syndrome with deletions within 15qll-13. J Med Genet 2673-77. Phelan MC, Albiez JL, Flannert DB, Stevenson RE (1988):The PraderWilli syndrome and albinism in a black infant. Proc Greenwood Genet Center 7:27-29. Robb SA, Pohl KR, Baraitser M, Wilson J, Brett EM (1989):The ‘happy puppet’ syndrome of Angelman: review of the clinical features. Arch Dis Child 64:83-86. Schwartz S, Max SR, Panny SR, Cohen MM (1985) Deletions of proximal 15q and non-classical Prader-Willi syndrome phenotypes. Am J Med Genet 20:255-263. Searle AG, Peter J, Lyon MF, Hall JG, Evans EP, Edwards J H , Buckle
VJ (1989): Chromosome maps of man and mouse. Ann Hum Genet 53:89-140. Wallis CE, Beighton PH (1989):Synchrony of oculocutaneous albinism, the Prader-Willi syndrome, and normal karyotype. J Med Genet 26:337-338. Wiesner GL, Bendel CM, Olds DP, White JG, Arthur DC, Ball DW, King RA (1987): Hypopigmentation in the Prader-Willi syndrome. Am J Hum Genet 40:431-442. Willems PJ, Dijkstra I, Brouwer OF, Smit GPA (1987):Recurrence risk in Angelman (“happy puppet”) syndrome. Am J Med Genet 27:773-780. Williams CA, Frias J L (1982):The Angelman (‘‘happy puppet”) syndrome. Am J Med Genet 11:453-460. Williams CA, Gray BA, Hendrickson J E , Stone JW, Cantu ES (1989): Incidence of 15q deletions in the Angelman syndrome: A survey of twelve affected patients. Am J Med Genet 32:339-345.
Diagnosis of Angelman Syndrome in Infants Julie Shapiro Fryburg, W. Roy Breg, and Valerie Lindgren Department of H u m u n Genetics, Yale University School of Medicine, New Haven, Connecticut The diagnosis of Angelman syndrome (AS) has seldom been made in infants because the previously described characteristic manifestations usually are not apparent until after age 2 years. We describe 4 AS patients, one of whom has oculocutaneous albinism, who were < 2 years old when first evaluated. All 4 have deletions of the region q11.2-q13of chromosome 15. In the 3 cases in which parents were available for study the deleted chromosome 15 was maternally derived, as determined by cytological markers. All of the patients presented with severe to profound global developmental delay and postnatal-onset microcephaly; they had seizures, hypotonia, hyperreflexia, and hyperkinesis. All were hypopigmented as compared to their relatives. Each had eye abnormalities; all had choroidal pigment hypoplasia. None were initially described as having an abnormal appearance. We believe that AS is far more common than previously thought and present these 4 children to emphasize the manifestations that may be helpful in making the diagnosis in the young patient. We alsa emphasize the hypopigmentation that patients with AS frequently have, including what we think is the first reported case of albinism and AS. KEY WORDS: chromosome 15 deletion, developmental delay, microcephaly, hypopigmentation, oculocutaneous albinism
teristic “puppet-like” gait and other movements [Angelman, 1965; Williams and Frias, 1982; Willems et al., 19871.So far approximately 70 patients with Angelman syndrome (AS) have been reported. Nearly all were diagnosed after age 2 years when the characteristic manifestations of the syndrome become more obvious. Recently we identified 3 patients with AS who were less than 2 years old and one patient, now 7% years old, who was an infant when first evaluated. Initially the diagnosis became apparent in 3 of these 4 patients when cytogenetic analysis detected deletions of the region q11.2-q13 of chromosome 15. Deletions of this region have been reported in about 60 percent of patients with AS [Imaizumi et al., 1990; Pembrey et al., 19891; the same deletion is also present in about the same proportion of patients with Prader-Willi syndrome (PWS) [Nicholls, et al., 19891. The diagnosis of AS was suspected in one of our 4 patients purely on clinical grounds, suggesting that it should be possible to delineate the characteristics of AS in infants and young children. We describe these 4 children with emphasis on the traits which may be helpful in making an early diagnosis, whether or not the deletion is present. One of these patients appears to be the first recognized patient to have documented AS and oculocutaneous albinism. In all 3 of our cases in which parents were available for study, the deleted chromosome 15 was maternally derived, as determined by cytologic markers. The maternal origin of the deleted chromosome 15 in our cases is consistent with the observation [Knoll et al., 19891that the deletions in AS are of the maternal chromosome 15 while the deletions in PWS are of the paternal chromosome 15.
CLINICAL REPORTS All 4 patients were referred to our genetics clinic by pediatric neurologists for evaluation of microcephaly INTRODUCTION and developmental delay. At the time of referral the In 1965 Angelman described 3 unrelated children patients ranged in age from 5% to 20 months. In each with mental retardation, microcephaly, paroxysms of case pregnancy histories, as well as maternal and paterlaughter, and seizure disorders. In addition they had eye nal perinatal exposures, were apparently normal. Famabnormalities, prominent jaw, large mouth, tongue pro- ily histories were unremarkable for mental retardation trusion, widely spaced teeth, absent speech, and charac- and microcephaly. An 8-year-old brother of patient 4 is dyslexic and a 6-year-oldbrother of patient 1,as well as the patient’s father and paternal grandfather, has atReceived for publication January 26,1990; revision May 9,1990. tention deficit disorder. The major common characteristics of these 4 patients Address reprint requests to Julie S. Fryburg, Yale University School of Medicine, 333 Cedar St., P.O. Box 3333, New Haven, CT can be grouped as follows: neurological, pigmentary, 06510. ophthalmic, and craniofacial (Table I). ~~
0 1991 Wiley-Liss, Inc.
Angelman Syndrome TABLE I. Clinical Findings in AS Patients
Neu r o1ogica1 Hypotonia Hyperreflexia Hyperkinesisipuppet-like movements Ataxiaidysmetria Developmental delayimental retardation Absentiminimal speech Microcephaly Inappropriate laughter Seizures Abnormal EEG Excessive drooling Tongue thrusting Opthalmic Choroidal pigment hypoplasia Strabismus Nystagmus Pigmentary Blue eyes Blond hair Oculocutaneous albinism Craniofacial Flat occiputihorizontal occipital groove Thin upper lipiwide mouth Prominent jawipointed chin Widely spaced teeth Cytogenetic 15q11.2-ql3 deletion Maternal derivation of deletion
1
Patienta 2 3
+ + + + + + + + + + + ++ +
+ + + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + + + +
+ + + + + + +
+ + + + +
+ + + +
NA
+ + -
+ + -
+ + + + + + -
"NA= not available for study
Neurological Manifestations The neurological manifestations of these patients include microcephaly, developmental delay, seizure disorders, and neuromuscular abnormalities. Each patient had birth weight, length, and head circumference (OFC) a t the 50th centile, but by age 6 months the OFC was not increasing consistently with other somatic growth. This trend is exemplified by patient 1(Fig. 11whose OFC was a t the 50th centile a t birth, at the 25th centile by age 3 months, a t the 10th centile by 7 months, and a t the 5th centile by 12 months. Since age 15 months her OFC has been well below the 3rd centile. Similar patterns are shown for the other 3 patients. All of the patients have severe to profound global developmental delay with minimal or absent speech, but no loss of any skills previously attained. Developmental assessments in all patients at 18 to 20 months placed their development a t a 7 to 8 month level. By 24 months only one patient was beginning to cruise. Although all of the patients are noted to have frequent vocalizations, only the 7I/z-year old patient has one word, mama, which she has had since about 3% years. By 10 months the patients had developed seizures of varying types, including absence seizures in one patient, myoclonic seizures in 2 patients, and tonic-clonic seizures in one patient. All of the patients had abnormal electroencephalograms characterized by multiple generalized bursts of irregular, high-voltage, 2-3 cps activity intermixed with spike and sharp wave activity. These findings are compatible with the patterns reported in other patients with AS [Bower and Jeavons, 1967; Moore and Jeavons, 1972; Kibel and Burness, 1973; Mayo e t al., 1973; Boyd et al., 19881. In 2 of the 4 patients seizures were very difficult to control. One of
56 I52
I
97% 50% 3%
48
Head 44 Circumference (ems) 40 36 32 I
t
28 I 0
I
I
4
I
I
8
I
I
12
59
I
I
16
I
I
20
I
I
24
I
I
1
28
Age (months) Fig. 1. Head circumferencesofpatients.Patient 1(small dashes),patient 2 (longdashes), patient 3 (solid light line), patient 4 (solid dark line).
60
Fryburg et al.
these patients, who is now T1/2 years old, has been clinically seizure-free since 3 years. This is consistent with the observation that patients with AS have more florid EEG changes and seizures recalcitrant to therapy in infancy and early childhood, but the seizures may ameliorate with advancing age [Boyd et al., 19881. While CT scans of the head were normal in 2 patients, magnetic resonance imaging demonstrated partial agenesis of the corpus callosum in the third patient and non-specific periventricular white matter loss in the fourth. Other evaluations for these neurologic abnormalities included routine cytogenetic analysis, thyroid function tests, blood chemistries, amino acids, lactate, pyruvate, urine genetic screen and organic acids, cerebral spinal fluid chemistries, and lysosomal enzyme assays, all of which were normal. By age 6 months all of the patients were described as hypotonic with brisk deep tendon reflexes. Also present since age 6 months have been occasional problems with swallowing and choking, which have been reported in other patients with AS [Moore and Jeavons, 19721. Excessive drooling and tongue thrusting were present a t 6 months and have become more pronounced and exaggerated over time. By 10 months all of the patients were noted to have frequent, jerky, erratic movements which made them appear hyperkinetic. All have histories of paroxysms of laughter by age 12 months. Two of the Datients (patients 2 and 3) have had dvsmetria on reaching for objects since age 10 and 12 months, respectively. The 71h-year-old has the characteristic ataxia with jerky movements of her arms and flapping of her hands commonly seen in older patients with AS.
Fig. 2. Patient 2 at age 24 months, seated with his mother, is hypoto the mother, pigmented as
Pigmentary Features All 4 our patients have blue eyes and have lighter hair and fairer skin than their relatives. Figures 2 and 3 demonstrate this contrast in coloring. The most striking example of this hypopigmentation is seen in patient 3 who has oculocutaneous albinism (OA). She is shown in Figure 4 at age 4 months when the diagnosis of OA was made on the basis of her fair skin with white hair and ophthalmologic examination which showed nystagmus, blond fundus, and transillumination of the iris. The diagnosis was confirmed by low hairbulb tyrosinase activity and characteristic hairbulb EM studies. The patient is photophobic and wears darkened glasses when exposed to the sun. Ophthalmic Manifestations All of the patients have ocular abnormalities. All 4 have choroidal pigment hypoplasia. One patient has strabismus and one has nystagmus; a 3rd patient has strabismus and nystagmus. The patient with albinism, as described above, has nystagmus, transillumination, and macular hypoplasia. The other 3 patients do not have iris transillumination and have foveal reflexes. Craniofacial Abnormalities All 4 patients were described a s having a normal facial appearance at 6 to 12 months. All had flat occiputs and 3 had horizontal occipital grooves. All smiled fre-
Fig. 3. Patient 1 a t age 26 months, shown with her brothers, is hypopigmented as compared to them (and parents, not shown here).
Angelman Syndrome quently and the smiling was often described as unprovoked, inappropriate, and prolonged. In 3 of the 4 patients the teeth were widely spaced. With advancing age certain facial changes typical of AS, such as the wide mouth with thin upper lip, prominent jaw, and pointed chin, appear more obvious (Figs. 4-6) [Robb et al., 19891.
CYTOGENETIC FINDINGS Chromosomes from each of the 4 patients were examined by using methotrexate synchronization and thymidine release to obtain cells with 550 or more bands. Three of the 4 cases each had a deletion of band q12 of one chromosome 15 and a portion of the flanking bands q11.2 and 913; the deletion in patient 2 may be slightly smaller and include only q11.2 and most of q12 (Fig. 7).
61
Patient 3 with albinism is adopted and her biologic parents were unavailable for study. However, the parents of the other 3 patients have normal chromosomes; thus, all 3 deletions are de novo. A study of the chromosome 15 heteromorphisms was performed on the 3 available families. In each case the deleted chromosome was maternally derived. Figure 8 illustrates the analysis of patient 2.
DISCUSSION We have described 4 children with AS to emphasize certain characteristics t h a t may be helpful in the early recognition of other young patients with AS. Manifestations of AS, especially of the face, appear to evolve over time [Baraitser et al., 1987; Robb et al., 19891. We do not yet know how early the diagnosis can be made on clinical
Fig. 4. Patient 3 with oculocutaneous albinism a t age 4 months (left),with no obvious anomalies; age 7% years (right),with the typical facial appearance of AS.
Fig. 5. Patient 1 at 20 months of age (left) and 26 months (right),demonstrating some of the subtle findings in AS, including wide mouth with thin upper lip, pointed chin, prominent jaw, and constant smiling and drooling.
62
Fryburg et al.
Fig. 6. Patient 4 a t age 12 months (left), 16 months (center), 24 months (right), illustrating t h e evolution of a patient with AS. Only very mild abnormality is present a t age 12 months. By 16 months changes i n her mouth, lips, and jaw a r e prominent. By 24 months these findings have become even more evident.
15
dell151
Fig. 7. Chromosome 15 deletions. The ideograms (center) show chromosomes 15 with an arrow pointing to band q12 in the normal chromosome (left). This band, as well as portions of the flanking bands q11.2 and q13, are absent from the deleted chromosome 15 (right), except in patient 2 where the deletion appears to be a bit smaller and to include only q11.2 and most of q12. Two pairs of chromosomes 15 from each patient are displayed with the normal chromosome on left and an arrow pointing to band q12. The deleted chromosome 15 is on right of each pair. Patient 1 (lower left), patient 2 (upper left), patient 3 (lower right), patient 4 (lower right).
grounds, but study of our patients indicates that the following features are probably present by age 6-12 months; post-natal onset microcephaly, developmental delay, seizure disorder, frequent hyperkinetic, movements of the trunk and limbs often with hypotonia and hyperreflexia, hypopigmentation, flat occiput, choroidal pigment hypoplasia, and paroxysms of laughter. The hyperkinesis and hypopigmentation appear to be quite characteristic of AS. Recognition of these features should lead to a highresolution chromosome study focused on chromosome 15, thus possibly avoiding unnecessary, expensive, and invasive investigations. Analysis of chromosomes of routine length in 3 of these 4 cases failed to show the deletion, which emphasizes the need to examine the chromosomes with high-resolution banding. In fact, the
deletion was missed in one patient even on high-resolution chromosomes when a nonfocused study was performed; however, when the chromosomes were reexamined in light of the clinical findings, the deletion was evident. It should be emphasized that detection of the deletion was invaluable in making the diagnosis of AS in these patients. If the deletions had not been found, we would have been reluctant to make the diagnosis. Since only about 60% of AS patients have a microscopically detectable deletion [Imaizumi et al., 1990; Pembrey et al., 19891, those infants with AS without a deletion will continue to be a diagnostic challenge. Ophthalmologic examination can detect choroidal pigment hypoplasia and other eye abnormalities [Massey and Roy, 19731, if present. An EEG may show characteristic changes, even in the absence of seizures [Boyd e t al., 19881.Presence of
Angelman Syndrome
63
nism, in PW6 [Hittner and King, 1982; Wiesner et al., 1987; Phelan et al., 1988; Butler, 1989; Wallis and Beighton, 19891 and in AS supports the notion that a geneb) on chromosome 15 is involved in pigment formation and deletion of this region results in varying degrees of hypopigmentation. Each of our patients has a deletion and hypopigmentation. However, there are cases of hypopigmented AS and PWS patients with normal chromosomes, a s well as normally pigmented AS and PWS patients who have the deletion [Pembrey et al., 1989; Williams et al., 19891. The exact mechanism of involvement of genes in this region in pigment production is not yet known. That hypopigmentation is common in both PWS and AS suggests that the postulated pigmentation gene is not involved in a n imprinting process. Further studies are needed to clarify these issues. Fig. 8. Patient 2 (bottom pair of chromosomes) inherited a normal chromosome 15 (left) with double satellites from his father (F). The abnormal chromosome 15 (right)is derived from a maternal (M) chromosome 15 with a large p11.2 region.
the common manifestations noted above, especially the hypopigmentation and hyperkinesis in a patient without a deletion, may make the diagnosis on clinical grounds alone. We think that AS is far more common than previously thought, as indicated by our identification of these 4 patients within a year’s span, as well as the increasing number of reports of AS [Magenis et al., 1987; Dorries et al., 1988; Robb et al., 19891. With recognition of the changes that we think are characteristic in infants, perhaps earlier diagnosis will be possible. The same deletion has been found in patients with PWS and in a few reported cases that did not, a t least initially, appear to have either PWS or AS [Schwartz et al., 19851. Thus far the deletions seem to be similar cytogenetically and molecularly [Donlon, 19881, yet they result in very different clinical syndromes [Magenis et al., 19871. Increasingly, it appears that deletions of a paternal chromosome 15 result in PWS while deletions of a maternal chromosome 15 result in AS [Knoll et al., 19891. The maternal origin of the deletion in AS, as opposed to the paternal origin in PWS, is substantiated in our patients. These findings have led to the hypothesis that this region of the genome is imprinted in some fashion (perhaps by methylation) such that maternal and paternal copies are not equivalent in development [Searle et al., 19891. Nicholls e t al., [1989] have recently demonstrated uniparental heterodisomy, i.e., inheritance of 2 different maternal chromosomes 15 and no paternal copy of chromosome 15, in several cases of PWS without deletions. It will be interesting to see if any of the patients who meet the clinical criteria for AS but have no detectable deletion will show uniparental disomy of paternal origin. Our patient with AS and OA strengthens the association of hypopigmentation with AS and this deletion. The presence of hypopigmentation, and in some cases albi-
ACKNOWLEDGMENTS We thank the patients’ family members for their cooperation, Drs. David Whiteman and Murray Engel for patient referrals, Drs. Laura Ment and Larry Wicker for their EEG interpretations, and Dr. Richard King for this involvement with ongoing pigment studies. REFERENCES Angelman H (1965):“Puppet” children: A report on three cases. Dev Med Child Neurol 7:681-683. Baraitser M, Patton M, Lam ST, Brett EM, Wilson J (1987):The Angelman (happy puppet) syndrome: is i t autosomal recessive? Clin Genet 31:323-330. Bower BD, Jeavons PM (1967):The “happy puppet” syndrome. Arch Dis syndrome. Arch Dis Child 42:298-302. Boyd SG, Harden A, Patton MA (1988):The EEG in early diagnosis of the Angelman (happy puppet) syndrome. E u r J Pediatr
147508-513. Butler MG (1989):Hypopigmentation: A common feature of PraderLabhart-Willi syndrome. Am J Hum Genet 45:140-146. Donlon TA (1988):Similar molecular deletions on chromosome 15q11.2 are encountered in both the Prader-Willi and Angelman syndromes. Hum Genet 80:322-328. Dorries A, Spohr HL, Kunze J (1988):Angelman (“happy puppet”) syndrome-seven new cases documented by cerebral computed tomography: review of the literature. Eur J Pediatr 148:270-273. Hittner HM, King RA (1982):Oculocutaneous albinoidism as a manifestation of reduced neural crest derivatives in the Prader-Willi syndrome. Am J Ophthalmol 94:328-337. Imaizumi K, Takada F, Kuroli Y, Naritomi K, Hamabe J, Nikawa N (1990):Cytogenetic and molecular study of Angelman syndrome. Am J Med Genet 35:314-318. Kibel MA, Burness FR (1973):“The happy puppet” syndrome. Cent Afr J Med 19:91-93. Knoll J H , Nicholls RD, Magenis RE,Graham J M , Lalande M, Latt SA (1989):Angelman and Prader-Willi syndromes share a common chromosome 15 deletion but differ in parental origin of the deletion. Am J Med Genet 32:285-290. Magenis RE,Brown MG, Lacy DA, Budden S, LaFranchi S (1987):Is Angelman syndrome a n alternate result of del(15)(qllq13)?Am J Med Genet 28:829-838. Massey JY, b y F H (1983):Ocular manifestations of the happy puppet syndrome. J Pediatr Ophthalmol 10:282-284. Mayo 0,Nelson MM, Townsend HR(1973):Three more ‘happy puppets’. Dev Med Child Neurol 1563-73. Moore JR, Jeavons PM (1973):The “happy puppet” syndrome: two cases and a review of five previous cases. Neuropadiatrie 4:172-179. Nicholls RD, Knoll J H , Butler MG, Karam S, Lalande M (1989):Ge-
64
Fryburg et al.
netic imprinting suggested by maternal heterodisomy in non-deletion Prader-Willi syndrome. Nature 342:281-285. Pembrey M, Fennel SJ, Van Den Berghe JV, Fitchett M, Summers D, Butler L, Clarke C, Griffiths M, Thompson E, Super M, Baraitser M (1989): The association of Angelman’s syndrome with deletions within 15qll-13. J Med Genet 2673-77. Phelan MC, Albiez JL, Flannert DB, Stevenson RE (1988):The PraderWilli syndrome and albinism in a black infant. Proc Greenwood Genet Center 7:27-29. Robb SA, Pohl KR, Baraitser M, Wilson J, Brett EM (1989):The ‘happy puppet’ syndrome of Angelman: review of the clinical features. Arch Dis Child 64:83-86. Schwartz S, Max SR, Panny SR, Cohen MM (1985) Deletions of proximal 15q and non-classical Prader-Willi syndrome phenotypes. Am J Med Genet 20:255-263. Searle AG, Peter J, Lyon MF, Hall JG, Evans EP, Edwards J H , Buckle
VJ (1989): Chromosome maps of man and mouse. Ann Hum Genet 53:89-140. Wallis CE, Beighton PH (1989):Synchrony of oculocutaneous albinism, the Prader-Willi syndrome, and normal karyotype. J Med Genet 26:337-338. Wiesner GL, Bendel CM, Olds DP, White JG, Arthur DC, Ball DW, King RA (1987): Hypopigmentation in the Prader-Willi syndrome. Am J Hum Genet 40:431-442. Willems PJ, Dijkstra I, Brouwer OF, Smit GPA (1987):Recurrence risk in Angelman (“happy puppet”) syndrome. Am J Med Genet 27:773-780. Williams CA, Frias J L (1982):The Angelman (‘‘happy puppet”) syndrome. Am J Med Genet 11:453-460. Williams CA, Gray BA, Hendrickson J E , Stone JW, Cantu ES (1989): Incidence of 15q deletions in the Angelman syndrome: A survey of twelve affected patients. Am J Med Genet 32:339-345.
