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Oculopharyngeal muscular dystrophy is a neuromuscular disease usually presenting in the 5th or 6th decades of life with a dominant inheritance pattern. In almost all cases the cause of the disease is the expansion of a DNA repeat sequence containing GCG and GCA codons in exon 1 of the PABPN1 gene from 10 to between 12 and 17 repeats. However one case has been previously reported without the gene expansion but instead with a c.35G>C missense mutation converting a glycine codon to an alanine and resulting in a sequence of 13 contiguous alanine codons, thus mimicking the effect of the common expansion mutation. Here we report two further cases of OPMD caused by the c.35G>C point mutation. Clinical and pedigree data indicate the usual OPMD dominant inheritance pattern.

Cultures of myoblasts isolated from cricopharyngeal muscles from patients with oculopharyngeal muscular dystrophy (OPMD) have been performed to study the effect of the expanded (GCG)8-13 repeat, located on the poly(A) binding protein nuclear-1 (PABPN1), on satellite cell phenotype. Cell cultures exhibited a reduced myogenicity, as well as a rapid decrease in proliferative lifespan, as compared to controls. The incorporation of BrdU decreased during the proliferative lifespan, due to a progressive accumulation of non-dividing cells. A lower fusion index was also observed, but myoblasts were able to form large myotubes when OPMD cultures were purified, although a rapid loss of myogenicity during successive passages was also observed. Myoblasts isolated from unaffected muscles did not show the defects observed in cricopharyngeal muscle cultures. The PABPN1 was predominantly located in nuclei of myoblasts and in both the nuclei and cytoplasm of myotubes in OPMD cultures. In vivo analysis of OPMD muscles showed that the number of satellite cells was slightly higher than that observed in age matched controls. Mutation of the PABPN1 in OPMD provokes premature senescence in dividing myoblasts, that may be due to intranuclear toxic aggregates. These results suggest that myoblast autografts, isolated from unaffected muscles, and injected into the dystrophic pharyngeal muscles, may be a useful therapeutic strategy to restore muscular function. Its tolerance and feasibility has been preclinically demonstrated in the dog.

The dominant oculo-pharyngeal muscular dystrophy mutation consists of an expanded (GCN)12‐17 in the coding region of the PolyA Binding Protein Nuclear 1 gene. A founder effect has been demonstrated in Canadian and Bukhara Jewish populations with relatively high prevalence of this disease. Since the oculo-pharyngeal muscular dystrophy prevalence was remarkably high in Southern Uruguay, a founder effect was hypothesized. To identify the ancestral haplotype we determined the (GCN) repeat number and the variants of four intragenic SNPs in Uruguayan OPMD families and a control sample. All families carrying the mutation (GCG)11(GCA)3(GCG) shared a common ancestral haplotype and the age of the mutation was estimated in 37‐53 generations by a composite likelihood method. One family carrying the (GCG)9(GCA)3(GCG) allele had a different haplotype. The genealogical and molecular data suggested that the common ancestors were Canary Islands’ settlers that arrived in Uruguay in the XIX century. q 2004 Elsevier B.V. All rights reserved.

Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant disorder of middle age presenting as progressive dysphagia and eyelid ptosis, due to short expansions of the GCG trinucleotide repeat (from GCG 6 to GCG 8–13 ) in the polyadenylate binding-protein nuclear 1 (PABPN1) gene. OPMD is rarely seen in Asians and morphologically and/or genetically confirmed cases have been reported in Japanese kindreds only. We report a 64 year old Chinese–Malaysian woman who presented with progressive dysphagia and bilateral ptosis for about 6 years. Her mother and elder brother (both deceased) were believed to be affected. Muscle histopathology revealed angulated fibres with rimmed vacuoles. Genetic analysis showed repeat expansion in one allele to (GCG) 9 while normal in the other (GCG) 6 . This is the first non-Japanese Asian family with genetically confirmed OPMD.