Mitochondrial DNA 3243A>T mutation in a patient with MELAS syndrome.

Approximately 80% of cases of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) harbor a heteroplasmic m.3243A>G transition in the tRNALeu (UUR) (MTTL1) gene. We report a MELAS case with a rare heteroplasmic m.3243A>T mutation found by direct sequencing of MTTL1. This mutation has been previously reported in 5 cases, of which 2 cases had the MELAS phenotype. Our case also strengthens the hypothesis that the m.3243A>T mutation can cause the MELAS phenotype.

Pelizaeus-Merzbacher disease can be a differential diagnosis in males presenting with severe neonatal respiratory distress and hypotonia.

Pelizaeus-Merzbacher disease (PMD; MIM #312080) is a rare X-linked recessive disorder. A male neonate presented with severe respiratory distress that required tracheostomy. After the appearance of nystagmus, PMD was suspected as a diagnosis for the patient, and a missense mutation, p.Phe51Val, was identified in PLP1, the gene responsible for PMD. PMD can be a differential diagnosis in a male neonate presenting severe respiratory distress.