A large homozygous microdeletion in the RAB3GAP1 gene causes Warburg Micro syndrome

Case Report: Warburg Micro syndrome (Micro syndrome, OMIM*600118) is characterized by microcephaly, microphthalmia, microcornea, congenital cataracts, optic atrophy, cortical dysplasia, severe mental retardation, spastic diplegia, and hypothalamic hypogonadism. This rare autosomal recessive syndrome is caused by mutations in the RAB3GAP1, RAB3GAP2, and RAB18 gene. Here, we delineate the fifteenth and so far largest homozygous microdeletion of exon 4 – 15 of the RAB3GAP1 gene (OMIM*602536) encompassing approximately 42.5 to 77 kb of chromosome 2q31 in a consanguineous Kurdish-Armenian family with two affected children. This mutation was identified by Sanger sequencing and confirmed by array CGH. Patients presented with a severe Warburg Micro syndrome phenotype. The parents are heterozygous for the identified deletion and are of normal phenotype.