Phenotypic variations in 3 children with POLG1 mutations.

Autosomal inherited mitochondrial diseases have been of increasing interest among clinicians and mitochondrial research groups because these diseases are caused through a secondary effect on the mitochondrial DNA. It was thought that the genetic stability of mitochondrial DNA relies on the accuracy of DNA polymerase gamma. Mutations of DNA polymerase gamma 1 gene (MIM# 174763) have been shown to be a cause of mitochondrial disorders associated with Mendelian disorders characterized by multiple mitochondrial DNA deletions or depletions. To date, several clinical phenotypes associated with polymerase gamma mutation have been reported presenting in both adults and children. We present 3 children in whom were found to have reported pathogenic DNA polymerase gamma 1 mutations: heterozygous p.G517V in 2 half siblings and heterozygous p.T251I and p.P587L in the other. The aim of this communication is to report 3 pediatric cases associated with DNA polymerase gamma 1 mutations to augment the expanding clinical phenotype that has been previously reported.