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Papers by Omar Abdul-rahman
Birth defects research. Part A, Clinical and molecular teratology, Jan 26, 2015
The National Children's Study (NCS) Vanguard Study began enrollment in January 2009 as an ini... more The National Children's Study (NCS) Vanguard Study began enrollment in January 2009 as an initial pilot study for a planned large-scale, longitudinal U.S. cohort study of the effect of environmental influences on child health and development, with biological and environmental sample collection conducted in seven locations from April 2009 to October 2010. We sought to determine rates of consent for, and success of collection of, maternal and paternal biospecimens before and during pregnancy in the NCS Vanguard Study. Samples of blood, saliva, vaginal swabs, urine, hair, and nails were collected before and during pregnancy. All specimens were sent to a central repository for processing, storage, and quality assessment. Of 780 pregnant women asked to consent to sample collection, 773 (>99%) agreed, and of 295 nonpregnant women, 292 (99%) agreed. Of 440 fathers asked to consent to sample collection, 435 (99%) agreed. Frequency of successful collection of biospecimens varied depen...
European Journal of Human Genetics, 2015
The Koolen-de Vries syndrome (KdVS; OMIM #610443), also known as the 17q21.31 microdeletion syndr... more The Koolen-de Vries syndrome (KdVS; OMIM #610443), also known as the 17q21.31 microdeletion syndrome, is a clinically heterogeneous disorder characterised by (neonatal) hypotonia, developmental delay, moderate intellectual disability, and characteristic facial dysmorphism. Expressive language development is particularly impaired compared with receptive language or motor skills. Other frequently reported features include social and friendly behaviour, epilepsy, musculoskeletal anomalies, congenital heart defects, urogenital malformations, and ectodermal anomalies. The syndrome is caused by a truncating variant in the KAT8 regulatory NSL complex unit 1 (KANSL1) gene or by a 17q21.31 microdeletion encompassing KANSL1. Herein we describe a novel cohort of 45 individuals with KdVS of whom 33 have a 17q21.31 microdeletion and 12 a single-nucleotide variant (SNV) in KANSL1 (19 males, 26 females; age range 7 months to 50 years). We provide guidance about the potential pitfalls in the laboratory testing and emphasise the challenges of KANSL1 variant calling and DNA copy number analysis in the complex 17q21.31 region. Moreover, we present detailed phenotypic information, including neuropsychological features, that contribute to the broad phenotypic spectrum of the syndrome. Comparison of the phenotype of both the microdeletion and SNV patients does not show differences of clinical importance, stressing that haploinsufficiency of KANSL1 is sufficient to cause the full KdVS phenotype.
PEDIATRICS, 2006
OBJECTIVE. We sought to further characterize the phenotype and facilitate clinical recognition of... more OBJECTIVE. We sought to further characterize the phenotype and facilitate clinical recognition of systemic hyalinosis in children who present with chronic pain and progressive contractures in early childhood.
Journal of Child Neurology, 2011
Krabbe disease is an infantile-onset progressive leukodystrophy. The classic presentation include... more Krabbe disease is an infantile-onset progressive leukodystrophy. The classic presentation includes excessive irritability, muscle hypertonicity, developmental delay, failure to thrive, peripheral neuropathy, seizures, and optic nerve atrophy. The authors report a rare case of optic nerve enlargement early in infantile Krabbe disease. Their case demonstrates proximal prechiasmatic enlargement of the nerves. They discuss the pathophysiological and clinical correlation of optic nerve enlargement in Krabbe disease and in other disorders. Although Krabbe disease does not feature in initial differential of optic nerve enlargement in children, its inclusion and early identification facilitate a timely diagnosis of this rapidly progressive fatal disease.
European Journal of Human Genetics, 2010
Human FOXP2 deficiency has been identified as a cause of hereditary developmental verbal dyspraxi... more Human FOXP2 deficiency has been identified as a cause of hereditary developmental verbal dyspraxia. Another member of the same gene family, FOXP1, has expression patterns that overlap with FOXP2 in some areas of the brain, and FOXP1 and FOXP2 have the ability to form heterodimers. These findings suggest the possibility that FOXP1 may also contribute to proper speech development. However, no such role of FOXP1 has been established to date. Recently, a child was reported who presented with a 3p13-14.1 deletion of four genes, including FOXP1, and a constellation of deficits that included speech delay. In this study, we report the case of a patient with a single deletion of FOXP1. This patient presented with speech and motor developmental delays, a Chiari I malformation, and epileptiform discharges. The nature of the speech deficit is different from the primary oromotor verbal dyspraxia found in patients with FOXP2 deficiency. The patient's developmental deficits may support a role for FOXP1 in the development of verbal and motor skills.
American Journal of Medical Genetics Part A, 2007
We describe our findings in a 46,XY female with a clinical features of Genitopatellar syndrome (G... more We describe our findings in a 46,XY female with a clinical features of Genitopatellar syndrome (GPS) and confirmed hermaphroditism with ovotestes, and five additional patients with GPS. GPS is a genetic disorder characterized by renal and genital anomalies, joint dislocation, aplastic or hypoplastic and often displaced patellae, minor facial anomalies, and mental retardation. The genital anomalies clearly distinguish GPS from nail-patella syndrome (NPS) that has similar features, but additionally shows hypoplastic fingerand toenails as found in the 46,XY female. In our patients no mutation was found in the coding regions of WNT4, WNT7A, TBX4, and LMX1B. Fluorescent in situ hybridization (FISH) and array-based comparative genome hybridization (aCGH) analysis showed a 3 Mb deletion of LMX1B, NR6A1, and NR5A1 (SF1) in the 46,XY female. This is the first report of a microdeletion causing haploinsuffiency of LMX1B and NR5A1. The deletion of LMX1B is responsible for the knee anomalies and the deletion of NR5A1 likely causes the sex reversal. Cytogenetic analysis of the five additional patients with diagnosed GPS failed to identify a similar microdeletion, or inversion of a potentially regulatory element between the two genes. This suggests that the locus 9q33-9q34 can be excluded for GPS and that the presented case is unique in its combination of GPS and NPS features caused by a microdeletion associated with loss of function of LMX1B and NR5A1. ß 2007 Wiley-Liss, Inc. . 2007. Ovotestes and XY sex reversal in a female with an interstitial 9q33.3-q34.1 deletion encompassing NR5A1 and LMX1B causing features of Genitopatellar syndrome. Am
American Journal of Medical Genetics, 2003
The American Journal of Human Genetics, 2012
Genitopatellar syndrome (GPS) is a skeletal dysplasia with cerebral and genital anomalies for whi... more Genitopatellar syndrome (GPS) is a skeletal dysplasia with cerebral and genital anomalies for which the molecular basis has not yet been determined. By exome sequencing, we found de novo heterozygous truncating mutations in KAT6B (lysine acetyltransferase 6B, formerly known as MYST4 and MORF) in three subjects; then by Sanger sequencing of KAT6B, we found similar mutations in three additional subjects. The mutant transcripts do not undergo nonsense-mediated decay in cells from subjects with GPS. In addition, human pathological analyses and mouse expression studies point to systemic roles of KAT6B in controlling organismal growth and development. Myst4 (the mouse orthologous gene) is expressed in mouse tissues corresponding to those affected by GPS. Phenotypic differences and similarities between GPS, the Say-Barber-Biesecker variant of Ohdo syndrome (caused by different mutations of KAT6B), and Rubinstein-Taybi syndrome (caused by mutations in other histone acetyltransferases) are discussed. Together, the data support an epigenetic dysregulation of the limb, brain, and genital developmental programs.
Molecular Genetics and Metabolism, 2016
Birth defects research. Part A, Clinical and molecular teratology, Jan 26, 2015
The National Children's Study (NCS) Vanguard Study began enrollment in January 2009 as an ini... more The National Children's Study (NCS) Vanguard Study began enrollment in January 2009 as an initial pilot study for a planned large-scale, longitudinal U.S. cohort study of the effect of environmental influences on child health and development, with biological and environmental sample collection conducted in seven locations from April 2009 to October 2010. We sought to determine rates of consent for, and success of collection of, maternal and paternal biospecimens before and during pregnancy in the NCS Vanguard Study. Samples of blood, saliva, vaginal swabs, urine, hair, and nails were collected before and during pregnancy. All specimens were sent to a central repository for processing, storage, and quality assessment. Of 780 pregnant women asked to consent to sample collection, 773 (>99%) agreed, and of 295 nonpregnant women, 292 (99%) agreed. Of 440 fathers asked to consent to sample collection, 435 (99%) agreed. Frequency of successful collection of biospecimens varied depen...
European Journal of Human Genetics, 2015
The Koolen-de Vries syndrome (KdVS; OMIM #610443), also known as the 17q21.31 microdeletion syndr... more The Koolen-de Vries syndrome (KdVS; OMIM #610443), also known as the 17q21.31 microdeletion syndrome, is a clinically heterogeneous disorder characterised by (neonatal) hypotonia, developmental delay, moderate intellectual disability, and characteristic facial dysmorphism. Expressive language development is particularly impaired compared with receptive language or motor skills. Other frequently reported features include social and friendly behaviour, epilepsy, musculoskeletal anomalies, congenital heart defects, urogenital malformations, and ectodermal anomalies. The syndrome is caused by a truncating variant in the KAT8 regulatory NSL complex unit 1 (KANSL1) gene or by a 17q21.31 microdeletion encompassing KANSL1. Herein we describe a novel cohort of 45 individuals with KdVS of whom 33 have a 17q21.31 microdeletion and 12 a single-nucleotide variant (SNV) in KANSL1 (19 males, 26 females; age range 7 months to 50 years). We provide guidance about the potential pitfalls in the laboratory testing and emphasise the challenges of KANSL1 variant calling and DNA copy number analysis in the complex 17q21.31 region. Moreover, we present detailed phenotypic information, including neuropsychological features, that contribute to the broad phenotypic spectrum of the syndrome. Comparison of the phenotype of both the microdeletion and SNV patients does not show differences of clinical importance, stressing that haploinsufficiency of KANSL1 is sufficient to cause the full KdVS phenotype.
PEDIATRICS, 2006
OBJECTIVE. We sought to further characterize the phenotype and facilitate clinical recognition of... more OBJECTIVE. We sought to further characterize the phenotype and facilitate clinical recognition of systemic hyalinosis in children who present with chronic pain and progressive contractures in early childhood.
Journal of Child Neurology, 2011
Krabbe disease is an infantile-onset progressive leukodystrophy. The classic presentation include... more Krabbe disease is an infantile-onset progressive leukodystrophy. The classic presentation includes excessive irritability, muscle hypertonicity, developmental delay, failure to thrive, peripheral neuropathy, seizures, and optic nerve atrophy. The authors report a rare case of optic nerve enlargement early in infantile Krabbe disease. Their case demonstrates proximal prechiasmatic enlargement of the nerves. They discuss the pathophysiological and clinical correlation of optic nerve enlargement in Krabbe disease and in other disorders. Although Krabbe disease does not feature in initial differential of optic nerve enlargement in children, its inclusion and early identification facilitate a timely diagnosis of this rapidly progressive fatal disease.
European Journal of Human Genetics, 2010
Human FOXP2 deficiency has been identified as a cause of hereditary developmental verbal dyspraxi... more Human FOXP2 deficiency has been identified as a cause of hereditary developmental verbal dyspraxia. Another member of the same gene family, FOXP1, has expression patterns that overlap with FOXP2 in some areas of the brain, and FOXP1 and FOXP2 have the ability to form heterodimers. These findings suggest the possibility that FOXP1 may also contribute to proper speech development. However, no such role of FOXP1 has been established to date. Recently, a child was reported who presented with a 3p13-14.1 deletion of four genes, including FOXP1, and a constellation of deficits that included speech delay. In this study, we report the case of a patient with a single deletion of FOXP1. This patient presented with speech and motor developmental delays, a Chiari I malformation, and epileptiform discharges. The nature of the speech deficit is different from the primary oromotor verbal dyspraxia found in patients with FOXP2 deficiency. The patient's developmental deficits may support a role for FOXP1 in the development of verbal and motor skills.
American Journal of Medical Genetics Part A, 2007
We describe our findings in a 46,XY female with a clinical features of Genitopatellar syndrome (G... more We describe our findings in a 46,XY female with a clinical features of Genitopatellar syndrome (GPS) and confirmed hermaphroditism with ovotestes, and five additional patients with GPS. GPS is a genetic disorder characterized by renal and genital anomalies, joint dislocation, aplastic or hypoplastic and often displaced patellae, minor facial anomalies, and mental retardation. The genital anomalies clearly distinguish GPS from nail-patella syndrome (NPS) that has similar features, but additionally shows hypoplastic fingerand toenails as found in the 46,XY female. In our patients no mutation was found in the coding regions of WNT4, WNT7A, TBX4, and LMX1B. Fluorescent in situ hybridization (FISH) and array-based comparative genome hybridization (aCGH) analysis showed a 3 Mb deletion of LMX1B, NR6A1, and NR5A1 (SF1) in the 46,XY female. This is the first report of a microdeletion causing haploinsuffiency of LMX1B and NR5A1. The deletion of LMX1B is responsible for the knee anomalies and the deletion of NR5A1 likely causes the sex reversal. Cytogenetic analysis of the five additional patients with diagnosed GPS failed to identify a similar microdeletion, or inversion of a potentially regulatory element between the two genes. This suggests that the locus 9q33-9q34 can be excluded for GPS and that the presented case is unique in its combination of GPS and NPS features caused by a microdeletion associated with loss of function of LMX1B and NR5A1. ß 2007 Wiley-Liss, Inc. . 2007. Ovotestes and XY sex reversal in a female with an interstitial 9q33.3-q34.1 deletion encompassing NR5A1 and LMX1B causing features of Genitopatellar syndrome. Am
American Journal of Medical Genetics, 2003
The American Journal of Human Genetics, 2012
Genitopatellar syndrome (GPS) is a skeletal dysplasia with cerebral and genital anomalies for whi... more Genitopatellar syndrome (GPS) is a skeletal dysplasia with cerebral and genital anomalies for which the molecular basis has not yet been determined. By exome sequencing, we found de novo heterozygous truncating mutations in KAT6B (lysine acetyltransferase 6B, formerly known as MYST4 and MORF) in three subjects; then by Sanger sequencing of KAT6B, we found similar mutations in three additional subjects. The mutant transcripts do not undergo nonsense-mediated decay in cells from subjects with GPS. In addition, human pathological analyses and mouse expression studies point to systemic roles of KAT6B in controlling organismal growth and development. Myst4 (the mouse orthologous gene) is expressed in mouse tissues corresponding to those affected by GPS. Phenotypic differences and similarities between GPS, the Say-Barber-Biesecker variant of Ohdo syndrome (caused by different mutations of KAT6B), and Rubinstein-Taybi syndrome (caused by mutations in other histone acetyltransferases) are discussed. Together, the data support an epigenetic dysregulation of the limb, brain, and genital developmental programs.
Molecular Genetics and Metabolism, 2016