Mondo Description Psychomotor retardation due to S-adenosylhomocysteine hydrolase deficiency is characterised by psychomotor delay and severe myopathy (hypotonia, absent tendon reflexes and delayed myelination) from birth, associated with hypermethioninaemia and elevated serum creatine kinase levels.

Uniprot Description A metabolic disorder characterized by hypermethioninemia associated with failure to thrive, mental and motor retardation, facial dysmorphism with abnormal hair and teeth, and myocardiopathy.