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Diseases

Genetic and Rare Diseases Information Center (GARD)

Oculopharyngeal muscular dystrophy


Other Names for this Disease
  • OPMD
  • Muscular dystrophy, oculopharyngeal
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Cause

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What causes oculopharyngeal muscular dystrophy (OPMD)?

OPMD is caused by mutations in the PABPN1 gene. The PABPN1 gene provides instructions for making the PABPN1 protein that is active (expressed) throughout the body. In cells, the PABPN1 protein plays an important role in processing molecules called messenger RNAs (mRNAs), which serve as genetic blueprints for making proteins. The protein acts to protect the mRNA from being broken down and allows it to move within the cell.

The PABPN1 gene contains a section of DNA called a GCN repeat, which normally repeats around 10 times. In cases of OPMD, this section of DNA is repeated 11-17 times. This results in extra production of a protein called alanine. The extra alanine causes the PABPN1 protein to form clumps within muscle cells that cannot be broken down. These clumps are thought to impair the normal function of muscle cells and eventually cause cells to die. The progressive loss of muscle cells most likely causes the muscle weakness seen in people with OPMD. It is not known why abnormal PABPN1 proteins seem to affect muscle cells in only certain parts of the body.[1][2]
Last updated: 6/15/2016

References
  1. Oculopharyngeal muscular dystrophy. Genetics Home Reference (GHR). December 2008; https://ghr.nlm.nih.gov/condition/oculopharyngeal-muscular-dystrophy.
  2. Capucine Trollet, Teresa Gidaro, Pierre Klein, Sophie Périé, Gillian Butler-Browne, Jean Lacau St Guily. Oculopharyngeal muscular dystrophy. GeneReviews. Februaru 20, 2014; http://www.ncbi.nlm.nih.gov/books/NBK1126/.


Other Names for this Disease
  • OPMD
  • Muscular dystrophy, oculopharyngeal
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.