Autism multiplex family with 16p11.2p12.2 microduplication syndrome in monozygotic twins and distal 16p11.2 deletion in their brother

AP-HP, Robert Debré Hospital, Department of Genetics, Cytogenetics Unit, Paris, France .
European journal of human genetics: EJHG (Impact Factor: 4.23). 01/2012; 20(5):540-6. DOI: 10.1038/ejhg.2011.244
Source: PubMed

ABSTRACT The pericentromeric region of chromosome 16p is rich in segmental duplications that predispose to rearrangements through non-allelic homologous recombination. Several recurrent copy number variations have been described recently in chromosome 16p. 16p11.2 rearrangements (29.5-30.1 Mb) are associated with autism, intellectual disability (ID) and other neurodevelopmental disorders. Another recognizable but less common microdeletion syndrome in 16p11.2p12.2 (21.4 to 28.5-30.1 Mb) has been described in six individuals with ID, whereas apparently reciprocal duplications, studied by standard cytogenetic and fluorescence in situ hybridization techniques, have been reported in three patients with autism spectrum disorders. Here, we report a multiplex family with three boys affected with autism, including two monozygotic twins carrying a de novo 16p11.2p12.2 duplication of 8.95 Mb (21.28-30.23 Mb) characterized by single-nucleotide polymorphism array, encompassing both the 16p11.2 and 16p11.2p12.2 regions. The twins exhibited autism, severe ID, and dysmorphic features, including a triangular face, deep-set eyes, large and prominent nasal bridge, and tall, slender build. The eldest brother presented with autism, mild ID, early-onset obesity and normal craniofacial features, and carried a smaller, overlapping 16p11.2 microdeletion of 847 kb (28.40-29.25 Mb), inherited from his apparently healthy father. Recurrent deletions in this region encompassing the SH2B1 gene were recently reported in early-onset obesity and in individuals with neurodevelopmental disorders associated with phenotypic variability. We discuss the clinical and genetic implications of two different 16p chromosomal rearrangements in this family, and suggest that the 16p11.2 deletion in the father predisposed to the formation of the duplication in his twin children.

1 Follower
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The short arm of chromosome 16 is rich in segmental duplications that result in chromosomal rearrangements through non-allelic homologous recombination. Several syndromes resulting from microdeletions or microduplications in this region have been reported. The chromosome 16p12.2-p11.2 deletion syndrome, 7.1- to 8.7-Mb [OMIM#613604] is characterized by minor facial anomalies, feeding difficulties, a significant delay in speech development, and recurrent ear infections. Reciprocal duplications of 16p12.2-p11.2 have been reported in some patients with autism. We identified a patient with a 16p12.2-p11.2 deletion and a patient with a 16p12.2-p11.2 duplication using oligonucleotide SNP array. The patient with the deletion showed severe developmental delay without autism. The patient with the deletion shared clinical features with previously reported patients. The patient with the duplication showed mild developmental delay and autism. She had dysmorphic features including a round face, a large mouth, and relative macrocephaly. We reviewed the reports of the two syndromes and compared the clinical manifestations. The 16p12.2-p11.2 duplication syndrome is a new syndrome with autism spectral disorders and dysmorphic features. © 2013 Wiley Periodicals, Inc.
    American Journal of Medical Genetics Part A 01/2014; 164(1). DOI:10.1002/ajmg.a.36217 · 2.05 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Chromosomal microarray analysis has identified many novel microdeletions or microduplications that produce neurodevelopmental disorders with a recognizable clinical phenotype and that are not observed in normal individuals. However, imbalance of other genomic regions is associated with a variable phenotype with intellectual disability (ID) or autism in some individuals but are also observed in completely normal individuals. Several large studies have reported the prevalence of copy number (CN) variants in people with particular features (e.g., ID, autism, schizophrenia, or epilepsy); few studies have investigated the prevalence of genomic CN changes in the general population. We used a high-throughput method to screen 6813 consecutive cord blood samples from a predominantly French-Canadian population to assess genomic CN in five genomic regions: 1p36, 15q11-q13, 16p11.2, 16p11.2-p12.2, and 22q11.2. We identified one deletion and one duplication within 1p36, two deletions of 15q11-q13, eight deletions of 16p11.2-p12.2, two deletions and five duplications of 16p11.2, and six duplications of 22q11.2. This study provides estimates of the frequency of CN variants in an unselected population. Our findings have important implications for genetic counseling.
    07/2013; 1(2):87-97. DOI:10.1002/mgg3.12
  • [Show abstract] [Hide abstract]
    ABSTRACT: Research suggests that the prevalence of obesity in children with autism spectrum disorder (ASD) is at least as high as that seen in typically developing children. Many of the risk factors for children with ASD are likely the same as for typically developing children, especially within the context of today's obesogenic environment. The particular needs and challenges that this population faces, however, may render them more susceptible to the adverse effects of typical risk factors, and they may also be vulnerable to additional risk factors not shared by children in the general population, including psychopharmacological treatment, genetics, disordered sleep, atypical eating patterns, and challenges for engaging in sufficient physical activity. For individuals with ASD, obesity and its sequelae potentially represent a significant threat to independent living, self-care, quality of life, and overall health.
    Harvard Review of Psychiatry 01/2014; 22(2):93-103. DOI:10.1097/HRP.0000000000000031 · 2.49 Impact Factor


Available from