Rare Glycogen Storage Diseases Natural History Study

Inclusion Criteria:

* 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 informed consent 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

Exclusion Criteria:

* Unable to provide informed consent for participation for one's self or by legally authorized representative/legal guardian/parent