GSD VI and GSD IX Natural History

Study Overview
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Brief Summary
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Collection and review of clinical information related to Glycogen Storage Disease Type VI (GSD VI) OR Glycogen Storage Disease Type IX (GSD IX) generated during clinic visits.

Detailed Description
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This natural history study will serve as a repository of clinical, laboratory, and biochemical information on individuals with GSD VI or GSD IX. This information will allow a more definitive description of glycogen phosphorylase (GP) and phosphorylase kinase (PhK) deficiency to be developed, which will permit development of treatment strategies for these diseases. Duke will be the only site where this study takes place. However, since these are rare disorders, participants who receive care at other institutions will be included. The investigators will collect retrospective data from patient charts on diagnosed individuals, as far back as necessary to capture the clinical course of the disorder. Prospective data collected from patient charts after enrollment will be captured as well. Participant's medical records will be continually reviewed for the duration of the study. Data will be collected from medical records and will only pertain to clinically relevant information, including, but not limited to: demographic and diagnostic information, tissue biopsy results, medical and family history, review of systems, imaging studies, results of liver and/or muscle testing, and urine and blood laboratory results.

Official Title
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GSD VI and GSD IX Natural History

Conditions
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Glycogen Storage Disease VI, GLYCOGEN STORAGE DISEASE IXa1, GLYCOGEN STORAGE DISEASE IXa2, Glycogen Storage Disease IXB, Glycogen Storage Disease IXC, GSD 9 (All Subtypes), GSD 6

Intervention / Treatment
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* Other: No intervention


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 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 Exclusion criteria: Unable to provide informed consent for participation for one's self or by legally authorized representative/legal guardian/parent

Ages Eligible for Study
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Minimum Age: 0 Years
Maximum Age: 90 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Other: No intervention|This is an observational study that consists of data abstraction from patient medical records.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Progression of disease confirmed by medical record review |  | through study completion, an average of 10 years | 
| Serum biotinidase activity |  | through study completion, an average of 10 years | 
| Number of genotypes presented |  | through study completion, an average of 10 years | 
| Number of phenotypes presented |  | through study completion, an average of 10 years |