Guanidinoacetate Methyltransferase (GAMT) Deficiency, A Cerebral Creatine Deficiency Syndrome: A Rare Treatable Metabolic Disorder

摘要

The prevalence ofcerebralcreatine deficiency syndrome(CCDS) has been estimated as 2.7%in childrenwith unexplained mentalretardation.[1]The prevalence ofCCDS in childrenwith autismspectrumdisorder has been reported to beless than 7 per 1000.[2] CCDS encompassesguanidinoacetate methyltransferase deficiency (GAMT-D), L-arginine:glycineamidinotransferase deficiency (AGAT-D),and creatinetransporter(CRTR) deficiency. Here, wereporta 29-months-old boywith socio-adaptiveand language delay,autistictraitsand hypotonia. GAMT-Dwasdiagnosed based on theelevated urinary excretion of guanidinoacetate(GAA),and identification ofa novel pathogenic variant inGAMT, the geneencoding guanidinoacetate methyltransferase. Thereare only fewreports of genetically confirmed GAMT-Dcases fromtheIndian subcontinent.