Variability of the recessive oculopharyngeal muscular dystrophy phenotype.
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.
Semmler
Alexander
A
Department of Neurology, University Hospital Bonn, Germany. alexander.semmler@ukb.uni-bonn.de
Kress
Wolfram
W
Vielhaber
Stefan
S
Schröder
Rolf
R
Kornblum
Cornelia
C
D000368:Aged; D000483:Alleles; D002883:Chromosomes, Human, Pair 14 / Q000235:genetics*; D005260:Female; D005808:Genes, Recessive; D014644:Genetic Variation; D006801:Humans; D008297:Male; D008875:Middle Aged; D039141:Muscular Dystrophy, Oculopharyngeal / Q000235:genetics*; D039122:Poly(A)-Binding Protein I / Q000235:genetics*; D017422:Sequence Analysis, DNA
D039122:Poly(A)-Binding Protein I