Familial inclusion body myositis among Kurdish-Iranian Jews
R. Massa, B. Weller, G. Karpati, E. Shoubridge and S. Carpenter
Neuromuscular Research Group, Montreal (Quebec), Neurological Institute, Canada.
We report two cases of adult-onset, slowly progressive limb-girdle muscle
weakness with a remarkable sparing of quadriceps muscles that developed in
patients from different families of Iranian-Kurdish-Jewish origin. Each
patient had a similarly affected sibling. The findings by means of muscle
biopsies showed abnormalities typical of inclusion body myositis, including
abundant lined vacuoles and characteristic cytoplasmic inclusions of 15- to
18-nm filaments. Remarkably, many vacuolated muscle fibers showed
immunoreactivity to neural cell adhesion molecule, a fetal muscle antigen.
The common origin of these patients from an isolated ethnic group with
frequent consanguinity and the familial incidence is indicative of a
genetic causation or predisposition, probably with an autosomal recessive
inheritance. This familial myopathy is one of several clinical syndromes
that share the typical pathological findings of inclusion body myositis.
The pathogenic relationship between these different familial forms and the
more common sporadic form of inclusion body myositis is not known.
