Hereditary Inclusion Body Myopathy - Mechanisms

Mechanisms

The exact mechanisms of these diseases are not well understood.

Hereditary inclusion body myopathy (IBM) constitutes a unique group of neuromuscular disorders characterized by adult-onset slowly progressive distal and proximal weakness, and a typical muscle pathology including rimmed vacuoles and filamentous inclusions. Autosomal dominant (IMB3; OMIM 605637 ) and autosomal recessive (IBM2; OMIM 600737 ) forms have been described. The autosomal recessive form, first characterized in Jews of Persian descent, is a myopathy that affects mainly leg muscles, but with an unusual distribution that spares the quadriceps, so-called quadriceps-sparing myopathy (QSM). This disorder was subsequently found in other Middle Eastern families, the gene was mapped to 9p13-p12, and in 104 affected persons from 47 Middle Eastern families the same mutation in homozygous state was found in the GNE gene. Affected individuals in families of other ethnic origins were found to be compound heterozygotes for other distinct mutations in the GNE gene. From OMIM 603824.