A GCG expansion (GCG)(11) in polyadenylate-binding protein nuclear 1 gene caused oculopharyngeal muscular dystrophy in a Chinese family

PURPOSE: To identify the mutation in polyadenylate-binding protein nuclear 1 gene (PABPN1, previously termed PABP2) in a Chinese family with autosomal, dominantly inherited oculopharyngeal muscular dystrophy (OPMD). METHODS: Clinical and ophthalmologic examinations were conducted on available living family members from three generations. Genomic DNA was extracted from peripheral blood leukocytes of every available family member, and the fragment flanking the (GCG)(n) of the PABPN1 gene was amplified by PCR. Mutations were screened by DNA sequencing. Photographs of deceased family members were examined for signs of OPMD. RESULTS: Clinical features of OPMD were found in all patients in generation II except the youngest sister, and no clinical manifestations were found in generation III. Mutation sequencing demonstrated that (GCG)(6) in the wild PABPN1 gene was expanded to heterozygous (GCG)(11) in all affected family members and in some but not all unaffected members. CONCLUSIONS: In a Chinese family with autosomal dominantly inherited OPMD, a heterozygous (GCG)(11) expansion was identified in all affected family members and in several young unaffected members.