Mitochondrial 3243 A to G mutation: clinical phenotypes on different stages of life and their relevance to heteroplasmy

Abstract

Mitochondrial 3243 A to G mutation is a major mutation, genetically causing mitochondrial diseases. It was first found in 1990 in a MELAS patient. One of the most prevalent pathogenic mutations, mitochondrial 3243 A to G mutation in mitochondrial DNA (mtDNA), is frequently linked to a variety of clinical phenotypes. The degree and prevalence of these symptoms differ, depending on variables including heteroplasmy levels (the percentage of mutant mtDNA), and life stage. Clinical phenotypes mainly include lactic acidosis, mitochondrial encephalomyopathy, stroke-like episodes (MELAS), maternally inherited diabetes and deafness, MERRF, CPEO and asymptomatic carriers as well as severe multisystem diseases. Till now, a lot of cohort studies have been performed to identify phenotypes connected with this mutation and a lot of phenotypes were found. Additionally, heteroplasmy level related studies were also performed. Different levels of heteroplasmy showed different phenotypes at different stages of life. The purpose of this study is to identify the clinical characteristics of the mutation at various phases of life and to emphasize the significance of heteroplasmy in the development and prognosis of disease.