Episodes of exercise-induced dark urine and myalgia in LGMD 2I

Acta Neurol Scand. 2012 Apr;125(4):285-7. doi: 10.1111/j.1600-0404.2011.01608.x. Epub 2011 Oct 27.


Background: Mutations in the fukutin-related protein gene FKRP (MIM *606596) cause a form of congenital muscular dystrophy (MDC1C) and also limb girdle muscular dystrophy type 2I (LGMD2I). Exercise-induced myoglobinuria, frequently occurring in metabolic myopathies, has been described in Becker muscular dystrophy and in a few cases of LGMD.

Objectives: To describe that episodes with myoglobinuria, often associated with exercise-induced myalgia, may be common and a presenting symptom in patients with LGMD2I.

Methods: Data on episodes of suspected myoglobinuria and myalgia were collected from the patient records on 14 patients with a diagnosis of LGMDI.

Results: Five LGMD2I patients reported recurrent episodes of dark urine and myalgia after exercise, and in three of them, this was the only symptom for several years.

Conclusions: We conclude that episodes compatible with exercise-induced myoglobinuria may be frequent in LGMD2I.

MeSH terms

  • Adult
  • Exercise*
  • Humans
  • Muscle, Skeletal / pathology
  • Muscular Dystrophies, Limb-Girdle / complications*
  • Muscular Dystrophies, Limb-Girdle / genetics
  • Muscular Dystrophies, Limb-Girdle / urine*
  • Mutation / genetics
  • Myoglobinuria / etiology*
  • Myoglobinuria / urine*
  • Phenotype
  • Recurrence