A Novel Mutation in the TSEN2 Gene Among Two Iranian Families with Pontocerebellar Hypoplasia Type 2B

Abstract

Background: Pontocerebellar hypoplasia is an autosomal recessive and neurodegenerative disorder divided into sixteen subtypes. Pontocerebellar hypoplasia type 2B (PCH2B) shows microcephaly combined with epilepsy extrapyramidal dyskinesia and chorea due to different homozygous or compound heterozygous pathogenic mutations in the TSEN2 gene. Objectives: This study was aimed to find the mutation responsible for pontocerebellar hypoplasia in two families with similar patients using the next-generation sequencing technique. Methods: Whole exome sequencing (WES) was performed for two individuals in families with microcephaly and developmental delay. A novel mutation was confirmed by Sanger sequencing and segregation analysis. Pathogenicity and the effect of mutation were investigated using different bioinformatics analyses. Results: WES showed a novel and potential pathogenic mutation in TSEN2 (p.R350Q: c.1049G>A). Sanger sequencing verified that both individuals were homozygote and that their parents were heterozygote for this variant. Conclusions: Our data can help enhance knowledge about the role of the TSEN2 gene in pontocerebellar hypoplasia. Also, our results can extend the list of mutations responsible for PCH2B and help find the correlation between the genotypes and phenotypes for this disorder.