guanidinoacetate N-methyltransferase deficiency
Definition An über rare autosomal recessive disorder (OMIM:612736) characterised by developmental delay and regression, mental retardation, severe disturbance of expressive and cognitive speech, intractable seizures, and movement defects.
Lab Severe depletion of creatine and phosphocreatine in the brain, and accumulation of guanidinoacetic acid in brain and body fluids.
Molecular pathology Defects of GAMT, which encodes a methyltransferase that converts guanidoacetate to creatine, cause cerebral creatine deficiency syndrome 2 (guanidinoacetate N-methyltransferase deficiency).
Synonyms Cerebral creatine deficiency syndrome 2, creatine deficiency syndrome due to GAMT deficiency, GAMT deficiency