OPMD is a rare form of autosomal-dominant, adult-onset muscular dystrophy. Multiple pedigrees have been identified, including French Canadian, French Norman, Italian, English, German, and Japanese. The largest cohort of OPMD patients in the United States has recently been described in individuals of colonial Spanish-American descent in northern New Mexico.5
This cohort consists of 216 patients from 39 different kindreds, encompassing four generations. Histopathology of striated muscle from patients with OPMD generally demonstrates intranuclear inclusions consisting of tubular filaments, and sometimes rimmed vacuoles.1,6
A defect of the polyadenylation binding protein 2 gene on chromosome 14q11, consisting of a (GCG)8–13 triplet-repeat expansion, has been identified in affected individuals.1,5,7–
Symptoms usually begin in the fifth or sixth decade of life, with the hallmark being bilateral, symmetric ptosis. Oropharyngeal dysphagia with pharyngo-oral or pharyngonasal regurgitation occurs in approximately 65% of cases,8
and external ophthalmoplegia with diplopia, changes in the quality of the voice, and varying amounts of facial, neck, and proximal limb weakness may develop. The diagnosis is made clinically with supportive evidence from family history, electromyogram, normal creatine kinase, and a negative edrophonium chloride test result, and can be confirmed by muscle biopsy. The differential diagnosis includes myasthenia gravis, Lambert-Eaton syndrome, and inflammatory myositis. Symptomatic treatment consists of blepharoplasty for ptosis and cricopharyngeal myotomy for dysphagia.