American Journal of Medical Genetics 4057-60 (1991)
Inversion-Duplication of Bands q13+ q21 of Human Chromosome 9 Sunny Luke, Ram S. Verma, Rhandy PeBenito, and Michael J. Macera Long Island College Hospital (SL, R.S.V., M.J.M.) and SUNY Health Science Center, Brooklyn, New York (R.S.V., M.J.M.)and Stanley S. L a m m Institute for Child Neurology and Developmental Medicine, Brooklyn, New York (R.P.) Structural abnormalities involving heterochromatic regions of the human genome are difficult to characterize because these s e g ments are G-band negative by GTG technique, a routinely used procedure in clinical cytogenetic laboratories. Chromosome abnormalities of such cases have gone undetected or were incorrectly characterized because these regions are so-called heteromorphisms or variants. Consequently, much anxiety has been aroused by the confusion between a chromosome abnormality and a normal heteromorphic variant. We report the first documented case with a so-called highly unusual h region of chromosome 9 which is not a variation but a structural rearrangement involving a paracentric inversion and a duplication. The major clinical features were psychomotor retardation, microcephaly, narrow palpebral fissures, renal and genital anomalies, vertebral anomalies, protruding tongue, and learning and behavioral problems. A concise review of variable duplicated segments of 9q is also provided.
KEY WORDS: 9q syndrome, inversion, duplication, heteromorphism, secondary constriction region INTRODUCTION Human chromosome 9 displays the highest degree of structural variability, mainly due to the amount and position of its paracentromeric heterochromatin, an area whose function(s1remaids) obscure [Verma, 19881. Numerous investigators have reported unusual findings involving this so-called secondary constriction region [Bobrow, 1985;Buys et al., 1979,1981; Hansmann, 1976; Madan, 1978; Madan and Bobrow, 1974; Martin Received for publication April 12, 1990; revision received July 12, 1990. Address reprint request to Dr. Ram S. Verma, Chief, Division of Genetics, Long Island College Hospital, Atlantic Ave and Hicks St, Brooklyn, New York 11201.
0 1991 Wiley-Liss, Inc.
and Abrisqueta, 1983; Silengo et al., 1982; Sutherland and Eyre, 19811. Consequently, much anxiety has been aroused by the confusion between a chromosome abnormality and a normal heteromorphic variant [Verma and Dosik, 1980; Verma et al., 1984; Verma, 19901. This is particularly true when the secondary constriction region is involved. We present such a case whose secondary constriction region (h) has an abnormal heterochromatic region that was originally thought to be an abnormality not involving the h region. To the best of our knowledge, this structural rearrangement involving the h region has not been reported previously. We also attempted to correlate our findings with earlier reported cases with variable duplication of 9q segments.
CLINICAL REPORT A 167/iz-year-oldhispanic woman was referred for a neurologic evaluation and follow-up of mental retardation and behavioral problems. The patient was reported to be the product of an apparently uncomplicated term pregnancy, labor, and delivery to a 25-year-old G6P5 mother. There was no history of exposure to any known teratogen. Her birth weight was 2,410 g. Except for a febrile illness at age 15 days for which she was hospitalized, her past history was unremarkable. She has not had her menarche. Shortly after she began school, she was noted to be slow. Evaluation indicated mental retardation requiring special class placement. She never learned to read or write. Unusual behavior is characterized by yelling, cursing, and destructibility. She speaks in short phrases in English and in Spanish. On examination, she appeared short and heavy. Her head was small and measured 49.5 cm (
Inversion-Duplication of Bands q13+ q21 of Human Chromosome 9 Sunny Luke, Ram S. Verma, Rhandy PeBenito, and Michael J. Macera Long Island College Hospital (SL, R.S.V., M.J.M.) and SUNY Health Science Center, Brooklyn, New York (R.S.V., M.J.M.)and Stanley S. L a m m Institute for Child Neurology and Developmental Medicine, Brooklyn, New York (R.P.) Structural abnormalities involving heterochromatic regions of the human genome are difficult to characterize because these s e g ments are G-band negative by GTG technique, a routinely used procedure in clinical cytogenetic laboratories. Chromosome abnormalities of such cases have gone undetected or were incorrectly characterized because these regions are so-called heteromorphisms or variants. Consequently, much anxiety has been aroused by the confusion between a chromosome abnormality and a normal heteromorphic variant. We report the first documented case with a so-called highly unusual h region of chromosome 9 which is not a variation but a structural rearrangement involving a paracentric inversion and a duplication. The major clinical features were psychomotor retardation, microcephaly, narrow palpebral fissures, renal and genital anomalies, vertebral anomalies, protruding tongue, and learning and behavioral problems. A concise review of variable duplicated segments of 9q is also provided.
KEY WORDS: 9q syndrome, inversion, duplication, heteromorphism, secondary constriction region INTRODUCTION Human chromosome 9 displays the highest degree of structural variability, mainly due to the amount and position of its paracentromeric heterochromatin, an area whose function(s1remaids) obscure [Verma, 19881. Numerous investigators have reported unusual findings involving this so-called secondary constriction region [Bobrow, 1985;Buys et al., 1979,1981; Hansmann, 1976; Madan, 1978; Madan and Bobrow, 1974; Martin Received for publication April 12, 1990; revision received July 12, 1990. Address reprint request to Dr. Ram S. Verma, Chief, Division of Genetics, Long Island College Hospital, Atlantic Ave and Hicks St, Brooklyn, New York 11201.
0 1991 Wiley-Liss, Inc.
and Abrisqueta, 1983; Silengo et al., 1982; Sutherland and Eyre, 19811. Consequently, much anxiety has been aroused by the confusion between a chromosome abnormality and a normal heteromorphic variant [Verma and Dosik, 1980; Verma et al., 1984; Verma, 19901. This is particularly true when the secondary constriction region is involved. We present such a case whose secondary constriction region (h) has an abnormal heterochromatic region that was originally thought to be an abnormality not involving the h region. To the best of our knowledge, this structural rearrangement involving the h region has not been reported previously. We also attempted to correlate our findings with earlier reported cases with variable duplication of 9q segments.
CLINICAL REPORT A 167/iz-year-oldhispanic woman was referred for a neurologic evaluation and follow-up of mental retardation and behavioral problems. The patient was reported to be the product of an apparently uncomplicated term pregnancy, labor, and delivery to a 25-year-old G6P5 mother. There was no history of exposure to any known teratogen. Her birth weight was 2,410 g. Except for a febrile illness at age 15 days for which she was hospitalized, her past history was unremarkable. She has not had her menarche. Shortly after she began school, she was noted to be slow. Evaluation indicated mental retardation requiring special class placement. She never learned to read or write. Unusual behavior is characterized by yelling, cursing, and destructibility. She speaks in short phrases in English and in Spanish. On examination, she appeared short and heavy. Her head was small and measured 49.5 cm (
