Phenotypic variants of A3243G mitochondrial DNA mutation in a Hungarian family

The first Hungarian case with typical features of mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) in a young girl is presented. MELAS is a multisystem disorder inherited by the mitochondrial DNA with onset typically in childhood. Our patient presented the first symptoms at the age of 6 years with recurrent vomiting, nausea and transient visual loss. Several stroke-like episodes followed gradually impairing motor abilities and mental development. Molecular analysis of the mitochondrial DNA confirmed a heteroplasmic A3243G transition. The maternal family members were also tested for the mutation in peripheral blood DNA. In the mother of the proband, who suffers from bilateral hypacusis the mutation was detected in 20% of heteroplasmy, while in one of her asymptomatic sisters the mutation was present in 10% only. The bilateral hypacusis of the mother may be associated with this mutation and seems to differentiate the pedigree reported here from others published in the literature.