We review the current knowledge about the genetic susceptibility to develop inflammatory inclusion body myositis, especially in relation to the increased presence of the HLA DR3 allele in patients with familial and sporadic forms, indicating an autoimmune predisposition. The main focus of the review is the clinical and genetic presentations of the various hereditary inclusion body myopathies. Criteria for diagnosis and classification of these myopathies are presented. The spectrum of the recessive forms of hereditary inclusion body myopathies currently linked to chromosome 9p1-q1 is described, with emphasis on the up-to-date status of the gene search for these forms.