The molecular basis of the congenital fibrosis syndromes.

The congenital fibrosis syndromes (CFS) are rare inherited strabismus syndromes that present as congenital, nonprogressive ophthalmoplegias with active and passive restriction of globe movement, and include classic and atypical forms of congenital fibrosis of the extraocular muscles (CFEOM) and Duane syndrome (DS). Although historically believed to result from primary extraocular muscle fibrosis, both neuropathologic and genetic studies support the hypothesis that these disorders result from aberrant development of motor nuclei in the midbrain and pons.