Rippling muscle disease: Evidence for phenotypic and genetic heterogeneity

Abstract

We describe the clinical features of a family with rippling muscle disease. Muscle stiffness and myalgia were the most prominent symptoms. Muscle rippling, although distinctive, was present in only 6 of the 11 affected family members, whereas persistent muscle contraction to muscle percussion was present in all affected adults. Although this persistent contraction resembled percussion myotonia, it was electrically silent and is therefore more aptly called “percussion contracture.” We also observed two clinical features not emphasized in previously reported kindreds: mild but asymptomatic weakness of face or proximal muscles was present in 5 of 11 affected members, and 5 individuals also complained of toe walking after a prolonged period of inactivity, reflecting the disproportionate involvement of the calf muscles. The pedigree suggested autosomal dominant inheritance. Our linkage analysis excluded the region on chromosome 1q identified in a previous linkage study. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 340–344, 2001