NEW FAMILIAL MITOCHONDRIAL ENCEPHALOPATHY WITH MACROCEPHALY, CARDIOMYOPATHY, AND COMPLEX-I DEFICIENCY

Two siblings presented with a new phenotype consisting of fatal progre ssive macrocephaly and hypertrophic cardiomyopathy. Onset of symptoms started in both patients at the end of the first month of life with ma ssive brain swelling causing macrocephaly and evolving to extensive br ain destruction. Light microscopy of the lesions showed extensive smal l-vessel proliferation and gliosis. A distinct deficiency of complex I of mitochondrial respiratory chain was established in cultured fibrob lasts, skeletal muscle, and heart muscle. Specific lack of complex I p rotein was demonstrated by two-dimensional gel electrophoresis.