GSD VI and GSD IX Natural History

• Diagnosis of GSD VI or GSD IX via:

• Two variants in the PYGL, PHKA1, PHKA2, PHKG1, PHKG2, or PHKB gene (or one variant with evidence of disease). Note: for males, one variant in the PHKA1 or PHKA2 gene is sufficient for inclusion.

• Deficient GP activity or PhK activity per enzymology

• Histology as confirmed by clinician

• Pregnant women with a diagnosis of GSD VI or GSD IX will be included

• 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