A Olgac, Y Tokgöz, N Güleray, M Kılıç

Abstract

Introduction: Glycogen storage disease type 0 (GSD 0) is a rare congenital metabolic disorder that occurs due to the deficiency of glycogen synthase enzyme, caused by loss-of-function mutations of GYS2. We present an unusual case of GSD 0. Case presentation: Sixteen-year-old male was admitted due to elevated transaminase levels, hepatomegaly, and hepatosteatosis. He did not reveal any history of hypoglycaemia. Medical history revealed the death of two siblings due to unknown aetiology. Severe ketonuria was present at fasting. Metabolic tests were inconclusive. Molecular genetic analysis was performed to unravel the underlying aetiology that revealed a previously reported homozygous c.736C>T; p.(Arg246Ter) variant in GYS2 (NM_021957), that is known to cause GSD type 0. Discussion: GSD type 0 is a very rare metabolic disorder that may be overlooked, mostly due to unspecific symptoms. No special diagnostic laboratory tests are available, and definitive diagnosis can only be made by molecular genetic analyses.