Limb-girdle muscular dystrophy type 2B

What is the cause of limb-girdle muscular dystrophy type 2B (LGMD2B)?

Limb-girdle muscular dystrophy type 2B (LGMD2B) is caused by changes to the DYSF gene. When a genetic change causes a disease, it is also known as a pathogenic variation. The DYSF gene provides instructions to make a protein called dysferlin. Dysferlin is found in the thin membrane (sarcolemma) that surrounds muscle fibers. Scientists believe dysferlin is involved in repairing muscle fibers damaged naturally through use and may also be involved in the control of muscle inflammation. When there is a pathogenic mutation in the DYSF gene, the instructions to make dysferlin are not correct, which means the protein is either not made at all or the protein that is made cannot do its job properly. Without working dysferlin, the muscles are not able to repair themselves correctly and may become inflamed too easily leading to further damage to the muscle. Over time, this leads to the muscle weakness and wasting associated with LGMD2B.

Last updated on 05-01-20

How is limb-girdle muscular dystrophy type 2B (LGMD2B) diagnosed?

Limb-girdle muscular dystrophy (LGMD) is typically suspected when a person develops muscle weakness and wasting in the legs and arms, usually in the areas closest to the hips and shoulders, but not elsewhere in the body. However, it is hard to diagnose which type of LGMD a person may have without further testing. The doctor may wish to take a thorough personal and family history and to run some laboratory tests. These tests may include:

Genetic testing of the DYSF gene may be ordered to confirm the diagnosis of LGMD2B and to help identify family members who are carriers of the disease.

Last updated on 05-01-20

How is limb-girdle muscular dystrophy type 2B (LGMD2B) inherited?

Limb-girdle muscular dystrophy type 2B (LGMD2B), and all subtypes of LGMD type 2, are inherited in an autosomal recessive manner. This means that people with LGMD2B have pathogenic variations (changes, formerly known as mutations) in both copies of the DYSF __gene in each cell of the body. We inherit one copy of each gene from our mother and the other from our father. People who have only one changed copy of the DYSF gene are known as carriers of the disease. Carriers of LGMD2B typically do not have any signs or symptoms of the disease. When two carriers of LGMD2B have children, each child has a:

  • 25% chance to have LGMD2B
  • 50% chance to be a carrier of LGMD2B like each parent
  • 25% chance to have inherited two working copies of the DYSF gene, so he or she is not a carrier and is not affected with the disease

Last updated on 05-01-20

What is the long-term outlook for people affected by limb-girdle muscular dystrophy type 2B (LGMD2B)?

In general, limb-girdle muscular dystrophy type 2B (LGMD2B) is a slowly progressive disease, meaning the muscle weakness slowly continues to worsen. Eventually, most people with LGMD2B require a wheelchair, but this may be years after the diagnosis. Muscle weakness affecting the heart muscles or muscles necessary for breathing is uncommon in people with LGMD2B. In rare cases, the progression of the disease may be more rapid, with people requiring a wheelchair in one or two years after symptoms begin.

Last updated on 05-01-20

How common or rare is limb-girdle muscular dystrophy, type 2B?

The exact prevalence of limb-girdle muscular dystrophy, type 2B (LGMD2B) is not known.

Several studies throughout the world have estimated the frequency of LGMDs. Different populations often have different frequencies of the various LGMDs. The overall frequency of all LGMDs has been estimated to be 5-70 people per 1 million in several countries. This is approximately 1 in 14,286 to 1 in 200,000. Some have estimated a slightly smaller prevalence range, from 1 in 14,500 to 1 in 123,000 people.

LGMD2B is thought to account for 3-19% of all LGMDs. In many studies, LGMD2A is the most common (accounting for 8-26% of all LGMDs).

Last updated on 05-01-20

How might limb-girdle muscular dystrophy type 2B (LGMD2B) be treated?

Unfortunately, there is no cure for limb-girdle muscular dystrophy type 2B (LGMD2B). Treatment options that may be recommended for people with LGMD2B may include:

It is recommended that people with LGMD2B be provided with social and emotional support to cope with the diagnosis. Other specialists that may be recommended include a neurologist, occupational therapist, nutritionist, and genetic counselor. No currently available medications can relieve or reverse the symptoms associated with LGMD2B. However, research is ongoing to try to determine if treatments such as gene therapy may be helpful in the future.

Last updated on 05-01-20

Name: Jewish Genetic Disease Consortium (JGDC) 450 West End Ave., 6A
New York, NY, 10024, United States
Phone: 855-642-6900 Toll Free: 866-370-GENE (4363) Fax : 212-873-7892 Email: info@jewishgeneticdiseases.org Url: http://www.JewishGeneticDiseases.org
Name: Muscular Dystrophy Family Foundation P.O. Box 776
Carmel, IN, 46082, United States
Phone: +1-317-615-9140 Email: info@mdff.org Url: https://mdff.org/ MDFF provides financial assistance, quality programs and services for the Muscular Dystrophy community in Indiana.
Name: Jain Foundation 2310 130th Ave., NE Suite B101
Bellevue, WA, 98005, United States
Phone: 425-882-1492 Email: info@jain-foundation.org Url: https://www.jain-foundation.org/
Name: Muscular Dystrophy Association MDA 222 S Riverside Plaza Suite 1500
Chicago, IL, 60606, United States
Toll Free: 1-833-275-6321 (Helpline) Email: resourcecenter@mdausa.org Url: https://www.mda.org
Name: Muscular Dystrophy UK 61A Great Suffolk Street
London, SE1 0BU, United Kingdom
Phone: (+44) 0 020 7803 4800 Toll Free: 0800 652 6352 (Helpline) Email: info@musculardystrophyuk.org Url: https://www.musculardystrophyuk.org/
Name: Muscular Dystrophy Foundation Australia 36-38 Henley Beach Rd
Mile End, 5031 , Australia
Toll Free: 0430-404-332 Email: accounts@supportmd.org.au Url: http://mdaustralia.org.au/
Name: Living with Limb-Girdle Muscular Dystrophy Url: https://www.facebook.com/groups/Living.with.LGMD/
Name: Limb Girdle Muscular Dystrophy (Beyond Labels & Limitations, Inc. Url: https://www.facebook.com/groups/29111827568/

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