2 new cases of pontocerebellar hypoplasia type 10 identified by whole exome sequencing in a Turkish family.

Pontocerebellar hypoplasia type 10 (PCH10) is a progressive autosomal recessive neurodegenerative disorder that has been recently described in association with cleavage and polyadenylation factor I subunit 1 (CLP1) mutations. To date, all reported cases have the same homozygous missense mutation in the CLP1 gene suggesting a founder mutation. CLP1 is an RNA kinase involved in tRNA splicing and maturation. There is evidence that the mutation is associated with functionally impaired kinase activity and subsequent defective tRNA processing. Through whole exome sequencing, we identified the same mutation in an extended family of Turkish origin. Both children presented with severe psychomotor delay, progressive microcephaly, and constipation. However, intrafamilial phenotypic variability is suggested due to the variability in their brain abnormalities and clinical features.