glycogen storage disease Ib obsolete glycogen storage disease IC true This class may be deprecated in future. There are two types of GSDI: glycogen storage disease type Ia (GSDIa) and glycogen storage disease type Ib (GSDIb). Two other forms of GSDI have been described, and they were originally named types Ic and Id. However, these types are now known to be variations of GSDIb; for this reason, GSDIb is sometimes called GSD type I non-a. https://ghr.nlm.nih.gov/condition/glycogen-storage-disease-type-i MONDO:0009289