EARLY-ONSET AUTOSOMAL-DOMINANT MYOPATHY WITH RIGIDITY OF THE SPINE - A POSSIBLE ROLE FOR LAMININ BETA-1

We describe 17 individuals from seven families with a slowly progressi ve, early onset, autosomal dominant myopathy with proximal muscle weak ness, calf hypertrophy, contractures, spinal rigidity and, in five of the adult cases, a cardiac conduction defect. A deficiency of the lami nin pi chain of the skeletal muscle fibres was found in the older indi viduals of these families, but not the younger members. Other laminin chains, dystrophin and the dystrophin-associated glycoproteins were no rmal. The age-related deficiency of the laminin beta 1 is restricted t o the skeletal muscle fibres and not the vascular tissue, suggesting t hat this may be a secondary phenomenon. These findings suggest that a laminin or a laminin-binding protein is implicated in some forms of do minant limb girdle myopathies. (C) 1997 Elsevier Science B.V.