Unusual triplet expansion associated with neurogenic changes in a family with oculopharyngeal muscular dystrophy

The occasional observation of neurogenic features in oculopharyngeal muscular dystrophy (OPMD) is unclear both in nosological and in etiological respects. Studies are reported here of a family with autosomal-dominant OPMD involving seven members over three generations. In three of them muscle biopsies were performed. Two of the patients (a 45-year-old sister and a 57-year-old brother of the third generation) were studied in more detail and, in addition to the typical changes of OPMD, showed a neurogenic component both by electrophysiology and morphology. Molecular genetic investigations revealed a repeat unit of (GCG/GCA)13 in the first exon of the poly(A)binding-protein2 gene in both siblings. A possible association of this unusually long triplet repeat extension with the atypical phenotype is considered and has to be verified in other cases.