MTDPS13 is a disorder characterized by mitochondrial respiratory chain defects and the depletion of mtDNA. Patients also exhibit fragmentation of the mitochondrial network and increased serum lactate, ammonia and alanine. The disorder results in encephalopathy, cerebral atrophy, leukodystrophy, white matter abnormalities, hypotonia, ataxia, seizures, gastroesophageal reflux disease, and muscle atrophy. Affected individuals also suffer from severe global developmental delay and a failure to thrive. Patients may display variable facial dysmorphia such as a narrow elongated face, protruding malformed ears, epicanthal folds and downslanting palpebral fissures of the eyes with thick eyebrows, a saddle nose, and an everted lower lip. Other less common features in MTDPS13 include microcephaly, plagiocephaly, cataracts, scoliosis, neutropenia, and recurrent infections. Similarly to other encephalomyopathic forms of mtDNA depletion syndromes, MTDPS13 is a severe disorder and may result in early lethality. Its onset is typicallyat birth or in early infancy. The disease does not appear to have a gender bias.However, the disorder does appear to have a racial predisposition, with most reported cases occurring in Arab families.
Diagnosis can be made based on laboratory analysis of mitochondrial respiratory chain defects and serum lactate levels as well as by genetic testing. Currently, there is no cure for the disorder and treatment is focused on supportive care.
