LGMD Genetic Testing Program: What You Need to Know

LGMD genetic testing program

In 2015, with support from Sanofi Genzyme, MDA launched the limb-girdle muscular dystrophy (LGMD) genetic testing program in partnership with EGL Genetics. Since then, more than 2,800 people have submitted DNA samples through MDA Care Centers and MDA Care Affiliates to EGL Genetics for testing.

Through this program, individuals with limb-girdle muscle weakness can be tested to find out if they have one of the known subtypes of LGMD or any of a number of other disorders that can sometimes cause similar symptoms (such as Emery-Dreifuss muscular dystrophy or Bethlem myopathy, for example).

The test is an important first step for anyone living with limb-girdle muscle weakness who has not received a definitive genetic diagnosis. That’s why MDA and Sanofi Genzyme are proud to work together to continue offering MDA’s LGMD genetic testing program.

Continue reading below for answers to some of the most common questions about the testing program, LGMD and MDA.

What is the LGMD genetic testing program?

MDA’s LGMD genetic testing program is designed to help determine specific types of LGMD or to help diagnose related diseases that sometimes may be mistaken for LGMD.

Why is it important to get a genetic diagnosis?

Genetic testing is important because a definitive diagnosis is the first step to effectively managing an individual’s neuromuscular disease. It can ensure the most appropriate treatment strategy, best outcomes and access to clinical trials or disease-specific patient registries.

How much will it cost to have genetic testing done?

Genetic testing is costly and not always covered by insurance, but through MDA’s LGMD testing program, we are able to help more individuals receive a confirmed genetic diagnosis at no cost.

Will my insurance be billed for the test?

No, your insurance will not be billed for this test. All testing costs will be covered by the Sanofi Genzyme grant supporting this program. Individuals and families will not incur any additional cost for genetic testing through this program.

How is the LGMD genetic test performed?

The simple test requires only a saliva or blood sample, which can be collected at any one of MDA’s Care Centers or Care Affiliates or by your local physician. From there, it is sent to EGL Genetics, and within three to four weeks, results are returned to the physician, who then shares the findings with individuals and their families.

What can the test identify?

Test results can help identify whether an individual has one of the known subtypes of LGMD or one of a number of other neuromuscular diseases that can present with similar symptoms.

What will I need to do?

If you suspect you may have limb-girdle muscle weakness but do not have a confirmed genetic diagnosis, speak with your physician. Schedule an appointment at your local MDA Care Center, Care Affiliate or with your local physician to complete the testing, which requires only a single saliva or blood sample. You also can reach out to your local MDA Family Care Specialist to inquire about the testing process.

If I have already participated in the testing program, can I retest if I did not get a definitive result?

At this time, the program is only open to individuals who have not previously submitted DNA samples for testing.

What if I have questions about the testing process or about results?

Be sure to consult with your physician or genetic counselor if you have questions about the testing process or about results. Once a person undergoes the testing, results are returned to the physician within three to four weeks. The physician will then share the findings with the individual and their family.

Must I be registered with MDA to qualify to be tested?

You must be registered with MDA to receive MDA’s LGMD genetic testing service. To register, contact the MDA National Resource Center at 800-572-1717 or resourcecenter@mdausa.org.

What is limb-girdle muscular dystrophy (LGMD)?

LGMD is a diverse group of disorders with many subtypes categorized by disease gene and inheritance. LGMD usually manifests in the proximal muscles around the hips and shoulders. The shoulder girdle is the bony structure that surrounds the shoulder area, and the pelvic girdle is the bony structure surrounding the hips. Collectively, these are called the limb girdles, and it is the observed weakness and atrophy (wasting) of the muscles connected to the limb girdles that has given this group of diseases its name.

What causes LGMD?

Genes are the codes, or recipes, that cells use to manufacture the various proteins needed by the body. The genes associated with LGMD normally encode proteins that play vital roles in muscle function, regulation and repair. When one of these genes contains a mutation (a flaw, such as missing or incorrect information) cells cannot produce the proteins needed for healthy muscles.

There are two major groups of LGMDs. Called LGMD1 and LGMD2, these two groups are classified by the respective inheritance patterns: autosomal dominant and autosomal recessive. If one copy of the abnormal gene is sufficient to cause the disease, it is said to be autosomal dominant; if two copies are needed then the inheritance pattern is autosomal recessive. For more details on the various inheritance patterns, see the NIH Genetics Home Reference.

Dozens of different genes, when mutated, have been shown to cause specific LGMD1 and LGMD2 subtypes. In these cases, the proteins associated with these genes are nonfunctional or deficient, and muscles are unable to function normally. Gradually, the muscles become weak enough that people experience the symptoms of limb-girdle muscular dystrophy.

In addition to the known LGMD1 and LGMD2 subtypes linked to specific genes, there are many cases of LGMD where the causative gene is not yet known (and the person is not identified to have a subtype-specific form of LGMD). Scientists are actively working to understand the causes of these unidentified subtypes of LGMD, because the more we understand about all the different causes of LGMD and the diverse ways that muscle can be compromised, the better chance we have of finding effective therapies to intervene in the pathological process.

What are the symptoms of LGMD?

The unifying features of the LGMDs are the weakness and atrophy of the limb-girdle muscles.  However, the age at which symptoms appear, and the speed and severity of disease progression can vary.

Individuals may first notice a problem when they begin to walk with a “waddling” gait because of weakness of the hip and leg muscles. They may have trouble getting out of chairs, rising from a toilet seat or climbing stairs. As this weakness progresses, the person may require the use of assistive mobility devices.

Weakness in the shoulder area may make reaching over the head, holding the arms outstretched or carrying heavy objects difficult. It may become increasingly hard to keep the arms above the head for such activities as combing one’s hair or arranging things on a high shelf. Some people find it harder to type on a computer or other keyboard and may even have trouble feeding themselves.

Some of the various LGMD subtypes also are characterized by additional symptoms. For example, the heart can be affected in some types of LGMD, with weakness of the heart muscle (cardiomyopathy) and/or abnormal transmission of signals that regulate the heartbeat (conduction abnormalities or arrhythmias).

Some disease subtypes also involve the muscles involved with breathing, and for that reason, respiratory function, along with cardiac function, should be monitored regularly.

Other symptoms may be present in some of the different subtypes of LGMD, including but not limited to: joint stiffness, muscle cramps, enlargement of calf muscles and involvement of distal muscles of the body such as those controlling the hands and feet.

What has MDA done to support people living with LGMD today?

  • MDA is proud of our decades-long approach to providing coordinated expert care through our nationwide network of more than 150 MDA Care Centers.
  • We have facilitated direct patient care to tens of thousands of individuals living with LGMD for more than half a century.
  • MDA is committed to continuing to increase quality and standards of care, and is proud of its ongoing collaborative efforts with policymakers and stakeholders in the neuromuscular and rare disease community, and beyond, to ensure that every effort possible is made to free individuals — and the families who love them — from the harmful effects of LGMD and related neuromuscular diseases.
  • MDA convenes annual conferences, where leading scientists, researchers and medical professionals specializing in neuromuscular disease confer and collaborate with the aim of accelerating scientific discoveries, drug development and clinical care.
  • We provide support and services to help improve quality of life and help our families thrive, including MDA Summer Camp for kids with LGMD and related neuromuscular diseases, the MDA’s National Resource Center, and educational events and materials.

How has MDA been involved in LGMD research?

MDA’s fingerprints are on nearly every major advance in neuromuscular disease research, with MDA-sponsored research having resulted in breakthroughs for treating diseases, and in increasing survival and quality of life.

MDA has invested more than $1 billion in neuromuscular disease research grants since 1950, with more than $57 million dedicated to research for LGMD.

Over the last five years, MDA has spent nearly $17 million on LGMD research.

For more information

To find an MDA Care Center near you, visit mda.org and type your state or ZIP code in the box and select “Find MDA in Your Community.”

For questions and one-on-one support with one of our trained resource specialists, contact the MDA National Resource Center at 800-572-1717 or resourcecenter@mdausa.org.

To read about one individual’s experience with the LGMD genetic testing program, see Genetic Testing Provides Answers and Hope.

MDA is grateful to Sanofi Genzyme for its support of our LGMD awareness activities and the testing program.