To determine the carrier frequency of GATM deficiency, we performed functional characterization of rare missense variants in GATM reported as heterozygous in the Exome Variant Server database.
Patients with unexplained IDD with and without myopathy should be assessed for AGAT deficiency by determination of urine/plasma GAA and cerebral creatine levels (via brain MRS), and by GATM gene sequencing.
There are two known disorders of creatine synthesis (both transmitted as autosomal recessive traits: arginine: glycine amidinotransferase (AGAT) deficiency; OMIM 602360; and guanidinoacetate methyltransferase (GAMT) deficiency (OMIM 601240)) and one disorder of creatine transport (X-linked recessive SLC6A8 creatine transporter deficiency (OMIM 300036)).
Creatine deficiency syndromes are a newly described group of inborn errors of creatine synthesis (arginine:glycine amidinotransferase (AGAT) deficiency and guanidinoacetate methyltransferase (GAMT) deficiency) and of creatine transport (creatine transporter (CRTR) deficiency).
Creatine deficiency syndromes are a newly described group of inborn errors of creatine synthesis (arginine:glycine amidinotransferase (AGAT) deficiency and guanidinoaceteate methyltransferase (GAMT) deficiency) and creatine transport (creatine transporter (CRTR) deficiency).