McArdle's disease with late-onset symptoms: case report and review of the literature.

Abstract

McArdle's disease with late-onset symptoms is an unusual cause for muscle disease in older patients. The case of a patient with McArdle's disease whose symptoms began at 60 years of age is presented, and seven previous cases of late-onset McArdle's disease reported since 1963 are discussed. In five of the eight patients, the clinical presentation was similar to the early onset disorder with exercise intolerance, cramps, and myoglobinuria. In contrast, the remaining three patients presented with fixed proximal limb and bulbar weakness. Electromyography confirmed a myopathic process in four of four patients. Results of the forearm ischaemic exercise test were positive in seven of seven patients with complete myophosphorylase deficiency; results of muscle biopsies were diagnostic in all patients. McArdle's disease with late-onset symptoms is rare and clinically more variable than the early onset disorder.

McArdle's disease presenting with asymmetric, late-onset arm weakness

“…5,7 Although the majority of patients present in the first two decades of life, there are occasional reports of individuals diagnosed in late adulthood who were relatively asymptomatic in their youth. 8,9,18 Including the present case, McArdle's disease has been described in 9 patients presenting after age 45 ( Table 1). The age of onset ranged from 49 to 74 years, with only the 74-year-old patient presenting later than our patient.…”

McArdle Disease and Pregnancy

“…Most of the patients present symptoms since childhood, but are only diagnosed in adult age 4 . This happens due to the fact that the patients and their families often ignore these symptoms 2,3,16 .…”

“…McArdle disease, despite being the most common of the glycogen storage diseases 1 , is a rare disease, which is sometimes diagnosed late in life 2,3 . The diagnosis is rarely made during childhood or adolescence 4 .…”

Atypical McArdle’s disease with asymmetric weakness and Atrophy

“…Adult onset cases have been reported mostly in the second decade of life but some late onset cases have been reported [7][8][9]. Nine cases with onset after 4th decade have been reported in literature.…”