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Failure to elevate ammonia on ischemic exercise

MedGen UID:
Concept ID:
HPO: HP:6000320


Normal subjects display an increase in the concentration of ammonia in the blood following an ischemic exercise test. This term refers to an increase in ammonia that is below the lower limit of normal. [from HPO]

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVFailure to elevate ammonia on ischemic exercise

Conditions with this feature

Glycogen storage disease, type V
MedGen UID:
Concept ID:
Disease or Syndrome
Glycogen storage disease type V (GSDV, McArdle disease) is a metabolic myopathy characterized by exercise intolerance manifested by rapid fatigue, myalgia, and cramps in exercising muscles. Symptoms are usually precipitated by isometric exercise or sustained aerobic exercise. Most individuals improve their exercise tolerance by exploiting the "second-wind" phenomenon with relief of myalgia and fatigue after a few minutes of rest. Age of onset is frequently in the first decade of life but can vary; however, diagnosis is typically delayed as myalgia and fatigability are dismissed/overlooked. Fixed muscle weakness occurs in approximately 25% of affected individuals, is more likely to involve proximal muscles, and is more common in individuals of advanced age. Approximately 50% of affected individuals have recurrent episodes of myoglobinuria that can – on occasion – eventually result in acute renal failure.

Recent clinical studies


Skard Heier M, Dietrichson P, Landaas S
Acta Neurol Scand 1986 Dec;74(6):479-85. doi: 10.1111/j.1600-0404.1986.tb07874.x. PMID: 3825503

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