Orphanet rare-disease nomenclature entry Orphanet_263297 (Glycogen storage disease due to glycogenin deficiency) can be described as follows. Glycogen storage disease type 15 is an extremely rare genetic glycogen storage disease reported in one patient to date. Clinical signs included muscle weakness, cardiac arrhythmia associated with accumulation of abnormal storage material in the heart and glycogen depletion in skeletal muscle. Also known as: GSD due to glycogenin deficiency, GSD type 15, GSD type XV, Glycogen storage disease type 15, Glycogen storage disease type XV, Glycogenosis due to glycogenin deficiency, Glycogenosis type 15, Glycogenosis type XV.