CONFIRMATION OF LINKAGE OF OCULOPHARYNGEAL MUSCULAR-DYSTROPHY TO CHROMOSOME 14Q11.2-Q13

Oculopharyngeal muscular dystrophy is a late-onset, autosomally domina nt disorder characterized by progressive ptosis, dysphagia, and extrem ity weakness. Linkage of oculopharyngeal muscular dystrophy to 14q11.2 -q13 has been reported in a series of French Canadian families. Haplot ype analysis in these data shows a single segregating disease chromoso me, suggesting a founder effect in this population. We ascertained and sampled for linkage studies 5 multigenerational American families wit h oculopharyngeal muscular dystrophy. Four of the 5 families have know n French Canadian ancestry while the fifth is of English/Scottish orig in. A peak multipoint lod score of 6.30 was obtained for the marker MY H7.1 in the families, confirming linkage to 14q11.2-q13. The English/S cottish family exhibited a different chromosomal haplotype for the ocu lopharyngeal muscular dystrophy alleles than did the families of Frenc h Canadian origin. These data suggest that this family may represent a second, possibly independent mutation in this disorder.