Koolen de Vries syndrome (KDVS; MIM 610443) is a genomic disorder caused by a recurrent microdeletion derived from nonallelic homologous recombination mediated by flanking segmental duplications. Clin Show more
Koolen de Vries syndrome (KDVS; MIM 610443) is a genomic disorder caused by a recurrent microdeletion derived from nonallelic homologous recombination mediated by flanking segmental duplications. Clinical manifestations of this syndrome are characterized by intellectual disability, hypotonia, a friendly behavior, distinctive facial features, and epilepsy. Herein, we report a case of 2 girls who revealed global developmental delay, mild facial dysmorphisms, friendly behavior, and epileptic seizure with a de novo 17q21.31 microdeletion detected by chromosomal microarray analysis (CMA). Conventional cytogenetics analysis by GTG-banding showed a female karyotype 46,XX for both girls. CMA revealed a microdeletion spanning approximately 500 kb in 17q21.31 in both girls, encompassing the following genes: Show less