LOCUS HETEROGENEITY IN AUTOSOMAL-DOMINANT CONGENITAL EXTERNAL OPHTHALMOPLEGIA (CFEOM)

Congenital external ophthalmoplegia (CFEOM) is an uncommon autosomal d ominant condition that has previously been mapped to the pericentromer ic region of chromosome 12 in seven families with no evidence of locus heterogeneity. We report three families with typical CFEOM. One famil y does not map to this region of chromosome 12 or to other chromosomal locations implicated in disorders of lid or ocular movement. Recombin ants in two CFEOM families potentially help to reduce the size of the candidate region on chromosome 12.