Preferred Label : Psychomotor retardation and myopathy due to S-adenosylhomocysteine hydrolase deficiency;
ICD-11 definition : This syndrome 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. It has been described in three unrelated
patients. Transmission appears to be autosomal recessive. Two causative mutations
have been identified in the gene encoding S-adenosylhomocysteine hydrolase (SAHH;
AHCY), an enzyme involved in methionine metabolism. A methionine-restricted diet,
together with creatine supplements, may partly improve the delayed myelination and
psychomotor development.;
ICD-11 synonym : Hypermethioninaemia due to S-adenosylhomocysteine hydrolase deficiency;
Origin ID : 215404985;
Currated CISMeF NLP mapping
This syndrome 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. It has been described in three unrelated
patients. Transmission appears to be autosomal recessive. Two causative mutations
have been identified in the gene encoding S-adenosylhomocysteine hydrolase (SAHH;
AHCY), an enzyme involved in methionine metabolism. A methionine-restricted diet,
together with creatine supplements, may partly improve the delayed myelination and
psychomotor development.
