PYGM Sequence Analysis

Clinical Use

Use

The PYGM Sequencing Analysis is performed to identify pathogenic variants associated with glycogen storage disease type V. Glycogen storage disease type V (GSDV), also known as McArdle Disease, is a metabolic disorder that affects the muscles and is characterized by exercise intolerance, rapid fatigue, myalgia, rhabdomyolysis, and cramping while exercising. Symptoms usually present during isometric exercise or sustained aerobic exercise. While age of onset is variable, symptoms are usually exhibited within the first decade of life. Approximately half of affected individuals exhibit recurrent episodes of myoglobinuria that can eventually lead to acute renal failure.

Special Instructions

If a variant to be tested has been previously identified in a family member, please use test code 3801. Detailed requirements are specified under that code. This test is essential for those diagnosed or suspected of having glycogen storage disease type V, enabling targeted intervention and support.

Limitations

This test may not detect all pathogenic variants, including those that lie outside the coverage of the sequencing assay or large deletions/duplications that may not be identified through standard sequencing. Negative results do not completely rule out the presence of a pathogenic variant, particularly if clinical suspicion persists.

Test Details