VARIOUS TYPES OF HEREDITARY INCLUSION-BODY MYOPATHIES MAP TO CHROMOSOME 9P1-Q1

Hereditary inclusion body myopathies are a clinically heterogeneous gr oup of disorders characterized by adult-onset, slowly progressive musc le weakness and typical histopathology: rimmed vacuoles and filamentou s inclusions. The disorders are usually inherited as an autosomal rece ssive trait. The gene responsible for the disease found in Iranian Jew s, who present with quadriceps-sparing myopathy, maps to chromosome 9p 1-q1. We address the question of whether hereditary inclusion myopathi es are genetically as well as clinically heterogeneous disorders. We m apped the disease gene segregating in two families of Afghani-Jewish a nd one family of Iraqi-Jemish descent to the chromosome 9 locus. Simil arly, the disease gene segregating in a non-Jewish family from India m apped to the same locus. By contrast, the disease gene segregating in a French-Canadian family in which affected individuals had central ner vous system involvement as well as hereditary inclusion body myopathy, did not map to this locus, We conclude that many but not all forms of autosomal recessive hereditary inclusion body myopathy are caused by a gene defect that maps to chromosome 9p1-q1.