Novel mutation in the RAB3GAP1 gene, the first diagnosed Warburg Micro syndrome case in Syria

Warburg Micro syndrome is a rare autosomal recessive disease due to mutation in the RAB3GAP1, RAB3GAP2, RAB18 and TBC1D20 genes. It is commonly seen in consanguineous marriages, characterized by optic (microcornea, microphthalmia, congenital cataracts), neurologic )microcephaly, corpus callosum hypoplasia, severe mental retardation( and hypogonadism; some non-typical findings could be present (cardiomyopathy, peripheral neuropathy). We report a novel homozygous mutation in the RAB3GAP1 gene in a 7-month-old boy from healthy nonconsanguineous parents from the same village in Syria, with bilateral congenital cataracts, hypogonadism, muscular hypotonia and severe developmental delay. Whole exome sequencing (WES) showed a homozygous mutation in the c.2195del p.(Pro732Glnfs*6) in exon 19 of the RAB3GAP1 gene, which is likely pathogenic and correlates with Warburg Micro syndrome type 1.