Novel compound heterozygous mutations in WDR62 gene leading to developmental delay and Primary Microcephaly in Saudi Family: A novel compound heterozygous mutation in WDR62gen

Objective: Primary microcephaly (MCPH) is a rare autosomal recessive disorder characterized by impaired congenital reduction of brain size along with head circumference and intellectual disability. MCPH is a heterogeneous disorder and more than twenty four genes associated with this disease have been identified so far. The objective of this study was to find out the novel genes or mutations leading to the genetic defect in a Saudi family with primary microcephaly.

Methods: Whole exome sequencing was carried out to find the novel mutation and the results was further validated using Sanger sequencing analysis. This study was done in the Center of excellence in Genomic Medicine and Research, King Abdulaziz University under KACST project during 2017 and 2018.

Results: We report a novel compound heterozygous mutations c.797C>T in exon 7 and c.1102G>A in exon 9 of the WD repeat domain 62 (WDR62) (OMIM 604317) gene in two affected siblings in Saudi family with intellectual disability, speech impediments walking difficulty along with primary microcephaly. Two rare, missense variants were detected in heterozygous state in the WDR62 gene in these two affected individuals from the heterozygous parents.

Conclusions: A compound heterozygous mutations c.797C>T in exon 7 and c.1102G> A in exon 9 of the WDR62 gene was identified. WDR62 gene is very important gene and mutation can lead to neuro developmental defects, brain malformations, reduced brain and head size. These results should be taken into consideration during prognostic discussions and mutation spectrum with affected patients and their families in the Saudi population.