Oculopharyngeal muscular dystrophy
Oculopharyngeal muscular dystrophy (OPMD) is classically an autosomal dominant condition most often found in people with French-Canadian ancestry (where it is estimated to affect 1 in 1,000 individuals), although there are some rarer recessively inherited mutations as well. Symptoms generally appear when the person is 40 to 60 years old. The most obvious manifestation is weakness of the eyelids, leading to ptosis (droopy eyelids). Sometimes eyelid surgery is needed to improve vision. Swallowing may also be affected, and foot drop is another common late symptom.
Defects in the polyadenylate binding protein gene PABPN1 are the cause of OMD. Most commonly, a wildtype (GCG)6 repeat encoding a polyalanine tract located at the N terminus of the PABPN1 protein expands to between (GCG)8-13 in affected individuals.
OPMD patients with French-Canadian ancestry can often trace their lineage to a particuar couple: Zacharie Cloutier Jr. and Madeleine Emard (also Aymard, Esmard), who married at La Rochelle,France (St-Barthélémi parish) on April 4, 1648. Zacharie Cloutier Jr. emigrated from France to Quebec in 1634 with his parents, Zacharie Cloutier Sr. and Saincte (or Xainte) Dupont. Madeleine Emard was the daughter of Jean Emard and Marie Bineau, from Niort (St-André parish, Deux-Sèvres, France). Jean Emard was a tailor and merchant. The Bineau family appear to have been the earliest known carriers of OPMD among French Canadians. In addition, in the 1940's, a Bineau from Niort had OPMD.