Arakawa Syndrome II

**Semantic type:** Disease or Syndrome

**Definition:** A rare autosomal dominant inherited metabolic disorder characterized by deficiency of the enzyme tetrahydrofolate-methyltransferase. It results in the abnormal metabolism of methylcobalamin. Signs and symptoms include mental retardation, megaloblastic anemia, hypotonia, epilepsy, and hepatosplenomegaly.

**Synonyms:** - Arakawa's Syndrome 2 - Arakawa's Syndrome II - Homocystinuria-Megaloblastic Anemia, cblG Complementation Type - Methionine Synthase Deficiency - Methylcobalamin Deficiency, cblG Type - Tetrahydrofolate Methyltransferase Deficiency - Tetrahydrofolate Methyltransferase Deficiency