CHROMOSOME 12-LINKED AUTOSOMAL-DOMINANT SCAPULOPERONEAL MUSCULAR-DYSTROPHY

Scapuloperoneal syndromes are characterized by their distribution of m uscle weakness and wasting. The reported pattern of inheritance has be en variable. Both neurogenic and myopathic forms of autosomally domina ntly inherited scapuloperoneal syndrome have been described. It has be en suggested that these are variants of other neuromuscular diseases. We examined 44 members from a family with 14 members affected with a s capuloperoneal syndrome. Physiological and histological analysis impli ed that this condition is predominantly myopathic. Linkage analysis wa s done to confirm the genetic etiology of the disease in this family a nd to evaluate the possibility that it is an allelic variant of other neuromuscular diseases. Genetic analysis demonstrated linkage of the d isease to chromosome 12, which makes it genetically distinct from othe r loci known to cause neuromuscular disease. Muscle fibers with hyalin e desmin-containing cytoplasmic inclusions in combination with focal m yopathic changes may be a disease-specific morphological marker of the disease.