Variability of the recessive oculopharyngeal muscular dystrophy phenotype

Muscle Nerve. 2007 May;35(5):681-4. doi: 10.1002/mus.20726.

Abstract

Oculopharyngeal muscular dystrophy (OPMD) is usually transmitted as an autosomal-dominant trait and characterized by an expansion from 6 to 8 or more GCG/GCA repeats in the poly-(A) binding protein nuclear 1 (PABPN1) gene on chromosome 14q11. Autosomal-recessive OPMD with a homozygous (GCG)7 expansion of PABPN1 has only been described in two Canadian patients, who showed a comparably mild phenotype, suggesting that it is less severe than the dominant form. We clinically and genetically characterized the first two reported cases of autosomal-recessive OPMD in Europe. Remarkably, both patients revealed severe and diverse phenotypes, with an unusual onset and atypical clinical course in one patient. Former studies found a 1%-2% frequency of the (GCG)7 allele, which theoretically produces an incidence of 1:10,000 of autosomal-recessive OPMD in the general population. We conclude that the apparent rarity of the autosomal-recessive form of OPMD may be due to the fact that genetic testing is generally administered only to patients with typical clinical features or a positive family history.

Publication types

  • Case Reports

MeSH terms

  • Aged
  • Alleles
  • Chromosomes, Human, Pair 14 / genetics*
  • Female
  • Genes, Recessive
  • Genetic Variation*
  • Humans
  • Male
  • Middle Aged
  • Muscular Dystrophy, Oculopharyngeal / genetics*
  • Poly(A)-Binding Protein I / genetics*
  • Sequence Analysis, DNA

Substances

  • Poly(A)-Binding Protein I