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Genetic and Rare Diseases Information Center (GARD)

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Oculopharyngeal muscular dystrophy

Other Names for this Disease
  • Muscular dystrophy, oculopharyngeal
  • OPMD
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Your Question

My husband has a family history of oculopharyngeal muscular dystrophy. I am worried that he may be affected. Can the symptoms of this condition occur at earlier ages in susequent generations? Could this condition affect sperm mobility? What are the chances that a child we have together could be affected? 

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is oculopharyngeal muscular dystrophy?

Oculopharyngeal muscular dystrophy (OPMD) is a genetic muscle disorder with onset during adulthood, most often between 40 and 60 years of age. This condition is characterized by slowly progressive muscle disease (myopathy) affecting the muscles of the upper eyelids and the throat.[1] There are two types of OPMD, which are distinguished by their patterns of inheritance. They are known as the autosomal dominant and autosomal recessive types.[2] Both types are caused by mutations in the PABPN1 gene.[1][2][3]
Last updated: 5/2/2012

What are the symptoms of oculopharyngeal muscular dystrophy?

Oculopharyngeal muscular dystrophy is characterized by muscle weakness that begins in adulthood, typically after age 40. The first symptom in people with this disorder is usually droopy eyelids (ptosis), followed by difficulty swallowing (dysphagia). The swallowing difficulties begin with food, but as the condition progresses, liquids can be difficult to swallow as well. Many people with this condition have weakness and wasting (atrophy) of the tongue. These problems with food intake may cause malnutrition. Some affected individuals also have weakness in other facial muscles.[2]

Individuals with oculopharyngeal muscular dystrophy may also have double vision (diplopia) and frequently have weakness in the muscles near the center of the body (proximal muscles), particularly muscles in the upper legs and hips. The weakness progresses slowly over time, and people may need the aid of a cane or a walker. Rarely, affected individuals need wheelchair assistance.[1][2] Life expectancy on this condition is not reduced.[4]

Last updated: 12/8/2008

What causes oculopharyngeal muscular dystrophy?

Oculopharyngeal muscular dystrophy (OPMD) is caused by mutations in the PABPN1 gene. The PABPN1 gene provides instructions for making a 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.[2]

Mutations in the PABPN1 gene that cause OPMD result in a PABPN1 protein that forms clumps within muscle cells, and hence they 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.[2]

Last updated: 5/2/2012

How is oculopharyngeal muscular dystrophy inherited?

Most cases of oculopharyngeal muscular dystrophy (OPMD) are inherited in an autosomal dominant manner, which means one copy of the altered (mutated) gene in each cell is sufficient to cause the condition. Individuals have two copies of each gene; one copy having been inherited from each parent. An individual with the autosomal dominant form of OPMD may have inherited the condition from an affected parent, or less commonly, the condition may occur for the first time in the affected individual. Each child of an affected individual with this form of OPMD has a 50% (1 in 2) chance to be affected and a 50% chance to be unaffected.

Less commonly, OPMD is inherited in an autosomal recessive manner, which means that both copies of the disease-causing gene in each cell must have a mutation for an individual to be affected. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene (and are referred to as carriers), but they typically do not show signs and symptoms of the condition.[2] When two carriers of an autosomal recessive condition have children, each child has a 25% (1 in 4) chance to be affected, a 50% (1 in 2) chance to be a carrier like each of the parents, and a 25% chance to be unaffected and not be a carrier. The children of an individual with autosomal recessive OPMD will always be carriers (obligate heterozygotes) for the disease-causing mutation. The risk of a child being affected if his/her parent has autosomal recessive OPMD is less than 1%.[5]

Last updated: 5/2/2012

Can the symptoms of oculopharyngeal muscular dystrophy occur at earlier ages in susequent generations (a phenomenon known as anticipation)?

The alanine triplet repeat in PABPN1 is mitotically and meiotically stable. Therefore,expansion of the triplet repeat in meiosis is rare. Clinical anticipation is not observed with this disease. However, severe cases of oculopharyngeal muscular dystrophy represent 5% to 10% of all cases. These individuals have earlier onset of ptosis and dysphagia (<45 years) and an incapacitating proximal leg weakness that starts before age 60 years.[4]
Last updated: 12/8/2008

Could being affected by oculopharyngeal muscular dystrophy affect sperm mobility?

After an extensive search of the resources available to us, we have not been able to identifiy any indication that sperm mobility is affected in individuals with oculopharyngeal muscular dystrophy. Likewise, there are no reports of problems with fertility in individuals as a result of this condition. If you have additional questions or concerns regarding this issue, we strongly recommend that you discuss them with your healthcare provider.
Last updated: 12/8/2008

What are the risks posed to any child that my husband and I would have to be affected by oculopharyngeal muscular dystrophy?

Any risk to your future offspring depends on your husband's health status. Testing of at-risk asymptomatic adults for oculopharyngeal muscular dystrophy is available. Click here to view the contact information for the laboratories conducting genetic testing for oculopharyngeal muscular dystrophy. Please note that most laboratories do not accept direct contact from patients and their families; therefore, you will need to work with a health care provider if you are interested in learning more about testing. Bear in mind as well that this testing is not useful in predicting age of onset, severity, type of symptoms, or rate of progression in asymptomatic individuals. When testing at-risk individuals for oculopharyngeal muscular dystrophy, an affected family member should be tested first to confirm that the disorder in the family is actually oculopharyngeal muscular dystrophy.[4]  

Genetic counseling may help you both better understand the above-mentioned testing, your husband's health status, and the risk of passing this disease on to the next generation. Visit the Services section of the resources page to find a list of online resources that can assist you in finding a genetics clinic near you.
Last updated: 12/8/2008