Behavior, brain, and genome in genomic disorders: finding the correspondences

Recurrent reciprocal copy number variants: Roles and rules in neurodevelopmental disorders

Deletions and duplications, called reciprocal CNVs when they occur at the same locus, are implicated in neurodevelopmental phenotypes ranging from morphological to behavioral. In this article, we propose three models of how differences in gene expression in deletion and duplication genotypes may result in deleterious phenotypes. To explore these models, we use examples of the similarities and differences in clinical phenotypes of five reciprocal CNVs known to cause neurodevelopmental disorders: 1q21.1, 7q11.23, 15q13.3, 16p11.2, and 22q11.2. These models and examples may inform some insights into better understanding of gene-phenotype relationships. © 2018 Wiley Periodicals, Inc. Develop Neurobiol 78: 519-530, 2018.

A case report of 22q11 deletion syndrome confirmed by array-CGH method

Velo-cardio-facial syndrome (VCFS) is caused by a submicroscopic deletion on the long arm of chromosome 22 and affects approximately 1 in 4000 persons, making it the second most prevalent genetic syndrome after Down syndrome and the most common genetic syndrome associated with cleft palate. Most of the 22q11.2 deletion cases are new occurrences or sporadic; however, in about 10 % of families, the deletion is inherited and other family members are affected or at risk for passing this deletion to their children. This report describes a 1.5 years-old male child with clinical signs of velo-cardio-facial syndrome (VCFS) presented with heart defect, soft cleft palate, developmental delay, acrocephaly, seizure, MRI abnormalities and descriptive facial feature, such as hypertelorism. Array-CGH test was done to confirm the diagnosis; the result revealed a 2.6 Mbp deletion in 22q11.2 chromosome that containing TBX1 and COMT genes. Our data suggest that haploinsufficiency of TBX1 gene is probably a major contributor to some of the syndrome characteristic signs, such as heart defect. Because of developmental delay and dysmorphic facial feature were observed in the index's mother and relatives, inherited autosomal dominant form of VCF is probable, and MLPA (multiplex ligation-dependent probe amplification) test should be performed for parents to estimate the recurrent risk in next pregnancy.