Rare Glycogen Storage Diseases Natural History Study

Who May Qualify: - Diagnosis of a rare GSD, including 0a, 0b, VII, X, XII, XIII, XV, PRKAG2 syndrome or Danon disease - Two variants in the gene associated with the specific GSD type (for autosomal recessive diseases) - One variant in the gene associated with the specific GSD type (for autosomal dominant or X-linked diseases) - Deficient enzyme activity in liver, muscle, skin fibroblast or other tissue - One variant in causative gene with evidence of disease, per a clinician - Histology as confirmed by a clinician - Able to provide willing to sign a consent form for self (adults) or affected individual (minor or adults with a legally authorized representative) - Able to provide consent for release of medical records - Pregnant women with a diagnosis of a rare GSD will be included Who Should NOT Join This Trial: - Unable to provide willing to sign a consent form for participation for one's self or by legally authorized representative/legal guardian/parent Always talk to your doctor about whether this trial is right for you.