RT Journal Article SR Electronic T1 Locus heterogeneity in autosomal dominant congenital external ophthalmoplegia (CFEOM). JF Journal of Medical Genetics JO J Med Genet FD BMJ Publishing Group Ltd SP 985 OP 988 DO 10.1136/jmg.35.12.985 VO 35 IS 12 A1 G C Black A1 R Perveen A1 E Hatchwell A1 A Reck A1 J Clayton-Smith YR 1998 UL http://jmg.bmj.com/content/35/12/985.abstract AB Congenital external ophthalmoplegia (CFEOM) is an uncommon autosomal dominant condition that has previously been mapped to the pericentromeric region of chromosome 12 in seven families with no evidence of locus heterogeneity. We report three families with typical CFEOM. One family does not map to this region of chromosome 12 or to other chromosomal locations implicated in disorders of lid or ocular movement. Recombinants in two CFEOM families potentially help to reduce the size of the candidate region on chromosome 12.