Type V Glycogen Storage Disease Clinical Presentation

Updated: May 02, 2022
  • Author: Isaac Omolade Ogunmola, MBBS; Chief Editor: George T Griffing, MD  more...
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Consider the following in the history:

  • Age at onset of symptoms depends on enzyme activity levels. Initial symptoms are cramps, fatigue, and pain after exercise. [7]

  • Because severity depends on enzyme activity, individual presentation is unique.

  • The rate of rise in oxygen consumption per unit time (VO2) is relative to work rate increases.

  • Some adults develop a progressive proximal weakness.

  • Some adults develop a fixed motor weakness.

  • The disorder has a unique "second-wind" phenomenon. [8] If a patient nearing fatigue slows exercise to a tolerable level, a point exists at which exercise may be increased again without previous symptoms [9] . According to Porcelli and colleagues, this phenomenon may be secondary to increased adrenergic response to exercise, influx of glucose, free fatty acids, and other substrates for muscle metabolism. [10]

  • Burgundy-colored urine is usually reported in patients but is not always present. It is thought to be a result of rhabdomyolysis after intense exercise.

  • Jones and colleagues report an unusual presentation of atypical chest pain and chronic troponinemia associated with hypertrophic cardiomyopathy among family members. [11]


Physical Examination

Physical examination is usually unremarkable in most patients. About 25% of patients may present with evidence of muscle hypertrophy. Proximal muscle wasting and weakness may be seen older patients. [5]

Consider the following in the physical examination:

  • Diagnosis is suggested by patient history.

  • Clinical findings may be absent upon physical examination.

  • Muscle strength and reflexes may be normal.

  • In later adult life, persistent weakness and muscle wasting may be present.

  • When clinical suspicion is present, diagnostic testing includes the ischemic forearm test, laboratory analysis, and electromyography.

  • About 10% of patients with GSD V may present with acute renal failure. [5]