Abstract
Oculopharyngeal muscular dystrophy is an autosomal dominant muscular dystrophy due to amplification of the GCG triplet in the polyadenylate binding protein nuclear 1 gene (PABPN1) located on chromosome 14q11.2-q13. The first symptoms, usually facial muscle weakness, frequently occur in the fourth or sixth decade; other symptoms include dysphagia, progressive ptosis of the upper eyelids as well as weakness of limb-girdle muscles and sometimes anal or urethral sphincter weakness.
The prevalence of the mutation varies depending on geographic region (the highest prevalence was found in Bukchara Jews in Izrael 1 : 600 and in Quebec 1 : 1,000 and very low in France 1 : 200,000). This mutation is very stable and shows no anticipation phenomenon.
We correlated the phenotype and genotype of 36 patients from five independent families and we found no correlation between the onset of symptoms, progression, severity of phenotype and number of triplet GCG repetitions. The prevalence of OPMD in the Czech Republic can only be estimated (35/10 million, i.e. 1 : 285,700) and carriers of mutation and permutation, respectively, are substantially more common, because the majority of young relatives of probands with 50% genetic risk refused presymptomatic testing.