Congenital nemaline myopathy: two patients with consanguineous parents, one with a progressive course.

Clinical, morphological and genetic data are presented on two unrelated children with congenital nemaline myopathy. In one of these, the weakness and hypotonia were progressive. The parents of both children were second cousins. These cases together with those already published suggest that the frequency of consanguineous marriages in parents of children with nemaline myopathy is increased. This is a further argument in favour of an autosomal recessive type of congenital nemaline myopathy in addition to the autosomal dominant variety.