NOVEL MUTATION IN THE MITOCHONDRIAL-DNA TRANSFER-RNA GLYCINE GENE ASSOCIATED WITH SUDDEN UNEXPECTED DEATH

We describe an A-to-G transition at nucleotide 10044 in the tRNA(Gly) gene of mitochondrial DNA in a sibship in which the proband died at ag e 8 years after a severe encephalopathy, a brother died of sudden an u nexpected death, and the other six siblings had a combination of sympt oms, including apparent life-threatening events and gastroesophageal r eflux. This novel mutation was very abundant (>90%) in liver and muscl e of the proband and in several tissues, including blood, from his aff ected siblings (range 91-99%) but was less abundant in blood from the asymptomatic mother (88%) and maternal grandmother (85%). Our findings further enlarge the spectrum of clinical presentations associated wit h mitochondrial DNA mutations.