Rippling muscle disease (RMD) is caused by dominant mutations of the caveolin-3 gene (CAV3), and presents with overlapping limb-girdle muscle weakness, elevated creatine kinase (hyper- CKemia), RMD, and distal myopathy. We report a patient with a CAV3 mutation who presented with myalgia, exercise-induced muscle stiffness, hyperCKemia, and percussion-induced rapid muscle contraction and muscle mounding. A familial genetic study revealed the same mutation in two family members, with physical examinations showing that both of them had rippling muscles.

The majority of patients who present with muscle pain does have a definable myopathic disorder in the usual sense, despite intensive evaluation. Currently, most of these individuals are diagnosed with the syndrome of fibromyalgia, a condition that has been discussed under a number of different names for approximately a century. Fibromyalgia is a form of nonarticular rheumatism characterized by widespread musculoskeletal aching and stiffness, as well as tenderness on palpation at characteristic sites, called tender points. The American College of Rheumatology in 1990 set criteria for diagnosis of fibromyalgia as that includes at least 3 months of widespread pain and the presence f at lest 11 of 18 specific tender points on examination.