Oculopharyngeal muscular dystrophy (OPMD), a polyalanine myopathy, occurs due to expansion of homo-polyalanine stretch in normal polyadenylating binding protein nuclear 1 (PABPN1) protein from Ala10 to Ala11-17.
Nuclear inclusions mimicking poly(A)-binding protein nuclear 1 inclusions in a case of inclusion body myopathy associated with Paget disease of bone and frontotemporal dementia with a novel mutation in the valosin-containing protein gene.
These results confirm that OPMD is caused by GCG short expansion and provides insights into the genetic mechanisms which may contribute to adult onset myopathy, confined to oculopharyngeal muscles.