Mapping a gene for congenital fibrosis of the extraocular muscles to the centromeric region of chromosome 12.

Congenital Fibrosis of the Extraocular Muscles (CFEOM) is an autosomal dominant, ocular disorder characterized by congenital, nonprogressive, bilateral ptosis and external ophthalmoplegia. The pathophysiology of this disorder is unknown and it is unclear if it has a primary neurogenic or myopathic etiology. We report linkage of this disorder, in two unrelated families, to markers in the pericentromeric region of human chromosome 12. D12S59 does not recombine with the disease giving a two-point lod score of 12.5 (theta = 0.00). D12S87 and D12S85 flank the CFEOM locus with two-point lod scores of 8.9 (theta = 0.03) and 5.4 (theta = 0.03) respectively, defining a region of 8 cM. These data establish a map location for CFEOM and demonstrate that this may be a genetically homogeneous disorder.