MELAS ASSOCIATED WITH MUTATIONS IN THE POLG1 GENE

Abstract

MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes) syndrome is a characteristic mitochondrial disorder caused by point mutations in the mitochondrial genome (mtDNA).1 In addition to primary mtDNA defects, mutations in nuclear genes essential for mtDNA maintenance are emerging as important causes of mitochondrial disease leading to secondary mtDNA changes including mtDNA depletion and multiple mtDNA deletions. Of particular interest are mutations in the mtDNA polymerase γ ( POLG1 ) gene, which are associated with a phenotypic spectrum ranging from Alpers syndrome to recessive ataxia and late-onset progressive external ophthalmoplegia (PEO).2–5 We describe a patient with strokelike episodes typical of MELAS due to mutation of POLG1 . ### Case history. A 28-year-old man was admitted to hospital at age 23 years because of acute onset of head jerking to the left side and vomiting, preceded by several days of visual scintillations and right-sided headache. He had been well until 2 years previously when it was noted that he had problems with coordination and concentration. Neurologic examination revealed left homonymous hemianopia, areflexia, and sensory ataxia. A few hours after admission, he developed left-sided focal seizures with secondary generalization leading to status epilepticus, which was successfully treated with clonazepam and …