ABSTRACT
Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes(MELAS) is one of the most common inherited mitochondrial diseases. This paper reports a rare mutation associated with MELAS syndrome, the m. 3252 A>G mutation in the MT-TL1 gene encoding the mitochondrial tRNALeu(UUR). The 6-year-old girl suffered from recurrent convulsion and lactic acidemia. The mtDNA sequencing detected a variant m. 3252A>G(MT-TL1 gene) in the proband and her maternal relatives. The heteroplasmic levels in peripheral blood and urine sediment were 66.53% and 97.42%, respectively, which were obviously higher than those of her maternal relatives. Together with 3 previously reported cases, the variant m. 3252A>G could be classified pathogenic. All the reported pathogenic variants in MT-TL1 gene were reviewed to explore the genotype-phenotype correlations of pathogenic variants in MT-TL1 gene.
