Limb-Girdle Muscular Dystrophy (LGMD)

Limb-girdle muscular dystrophy (LGMD) is a group of rare muscular dystrophies that cause muscle weakness in your shoulders, upper arms, hips and upper legs. There are several different subtypes based on which gene has a mutation. Treatment involves managing symptoms with various strategies, like physical therapy, assistive devices and medications.

Overview

What is limb-girdle muscular dystrophy?

Limb-girdle muscular dystrophy (LGMD) is an umbrella term that represents several rare types of muscular dystrophy that cause muscle weakness in your shoulders, upper arms, hips and upper legs. LGMD is a chronic (lifelong) condition that affects people of all ages.

Your “limb girdles” are the bony structures that surround your shoulder and pelvic areas. LGMD affects the muscles around these areas.

Muscular dystrophy refers to a group of genetic conditions that affect the functioning of your muscles. In general, the symptoms of muscular dystrophy worsen over time.

How common is limb-girdle muscular dystrophy?

Limb-girdle muscular dystrophy is rare. All the subtypes combined affect about 2 in every 100,000 people in the United States. In comparison, Duchenne muscular dystrophy, the most common form of muscular dystrophy, affects about 1 in 3,600 males in the U.S.

The most common subtype of limb-girdle muscular dystrophy in the U.S. is LGMD R1 calpain3-related (calpainopathy). It accounts for 12% to 30% of all LGMD cases.

Symptoms and Causes

What are the symptoms of limb-girdle muscular dystrophy?

The main symptoms of limb-girdle muscular dystrophy are muscle weakness and atrophy (loss) in the following areas:

• Shoulders.
• Upper arms.
• Hips.
• Upper legs.

The age at which symptoms begin and the rate at which they get more severe varies depending on the subtype of LGMD.

Issues with walking may be the first sign of LGMD. Specific symptoms related to hip and upper leg muscle weakness include:

• A waddling gait (walking pattern).
• Difficulty rising from a seated position (like from a chair or toilet).
• Difficulty climbing stairs.

Specific symptoms related to shoulder and upper arm muscle weakness include difficulty with:

• Reaching over your head.
• Holding your arms outstretched.
• Carrying heavy objects.
• Feeding yourself.

Certain subtypes of LGMD have additional symptoms. They may include:

• Heart issues, like cardiomyopathy, conduction abnormalities or arrhythmias.
• Difficulty breathing.
• Difficulty swallowing (dysphagia).
• Joint stiffness (contractures).
• Muscle cramps.
• Enlarged calf muscles (hypertrophy).
• Weakness in more distant (distal) muscles, like those in your hands and feet.

What are the possible complications of limb-girdle muscular dystrophy?

Your likelihood of complications depends on several factors, including:

• The subtype of LGMD you have.
• The age of onset and how quickly the condition is progressing.
• Your access to thorough medical care and symptom management.

Possible complications include:

• Developmental delays in gross motor skills (like walking) in early-onset LGMDs.
• Intellectual disability and learning differences.
• Kyphosis and/orscoliosis — mainly in childhood-onset LGMD.
• Restrictive lung disease leading to respiratory insufficiency or respiratory failure.
• Malnutrition due to issues with eating and swallowing.

What causes limb-girdle muscular dystrophy?

Mutations (changes) in the genes that are responsible for healthy muscle structure and function cause limb-girdle muscular dystrophy. The mutations mean that the cells that would normally maintain your muscles can no longer fulfill this role, leading to progressive muscle weakness over time. There are specific gene mutations for each subtype of LGMD.

You can inherit these genetic mutations from your biological parents. There are two major groups of limb-girdle muscular dystrophy based on how you inherit the mutations:

• The LGMD D group: These LGMDs happen due to autosomal dominant inheritance patterns. This means you only need to inherit the mutated gene from one of your biological parents to develop the condition.
• The LGMD R group: These LGMDs happen due to autosomal recessive inheritance patterns. This means you’ve inherited a genetic mutation that causes the condition from both of your biological parents.

Types of limb-girdle muscular dystrophy

There are several subtypes of limb-girdle muscular dystrophy. Researchers and healthcare providers have a specific naming structure to categorize the different subtypes. It includes “LGMD” in addition to the:

• Type of inheritance: “D” stands for autosomal dominant inheritance. “R” stands for autosomal recessive inheritance.
• Order of discovery: Each subtype has a number based on the order in which researchers discovered it.
• Protein or gene that’s affected: This is represented by “[name of gene or protein]-related.”

Autosomal recessive subtypes of LGMD include:

Autosomal dominant subtypes of LGMD include:

Diagnosis and Tests

How is limb-girdle muscular dystrophy diagnosed?

If you or your child has symptoms of limb-girdle muscular dystrophy, your healthcare provider will likely do a physical exam, neurological exam and muscle exam. They’ll ask detailed questions about your symptoms and medical history.

If they suspect you or your child has LGMD, they may recommend any of the following diagnostic tests:

• Creatine kinase blood test: Your muscles release creatine kinase when they’re damaged, so elevated levels may indicate muscular dystrophy.
• Genetic tests: Genetic tests can identify gene mutations that are linked to certain subtypes of LGMD. This is the only test that can confirm the specific subtype.
• Muscle biopsy: Your provider may take a small sample of your muscle tissue. A specialist will then look at the sample under a microscope to look for signs of muscular dystrophy.
• Electromyography (EMG): This test measures the electrical activity of your muscles and nerves.

If you or your child have LGMD, your provider will likely also recommend heart and pulmonary (lung) function tests to see if the condition has affected those aspects of your health

Management and Treatment

What is the treatment for limb-girdle muscular dystrophy?

There’s currently no cure for limb-girdle muscular dystrophy, though researchers are actively looking for one.

The main goal of treatment is to manage symptoms and improve your quality of life. Treatments can vary depending on the type of LGMD and may include:

• Physical and occupational therapies: The main goal of these therapies is to strengthen and stretch your muscles. They can help you maintain movement function and find easier ways to do everyday tasks.
• Corticosteroids: Corticosteroids, such as prednisoloneanddeflazacort, may be beneficial for delaying muscle weakness, improving lung function, delaying scoliosis and slowing the progression of cardiomyopathy. Corticosteroids may only be beneficial for a few subtypes of LGMD, especially LGMD R9 FKRP-related.
• Mobility aids: Devices such as canes, braces, walkers and wheelchairs can improve your mobility and help prevent falls. They can also help reduce fatigue.
• Surgery: Some people with LGMD may need surgery to relieve tension on contracted muscles and to correct spine curvature (scoliosis).
• Respiratory care: Cough-assist devices and respirators can help with breathing. Tracheostomy and assisted ventilation may be necessary in cases of respiratory failure.
• Heart care: Early treatment with ACE inhibitors and/or beta-blockers may slow the progression of cardiomyopathy and prevent the onset of heart failure. Pacemakers can also help treat heart rhythm problems and heart failure.
• Speech therapy: This therapy can help if you have difficulty swallowing.
• Clinical trials: Depending on the type of LGMD you have and where you live, you may be able to participate in a clinical trial. An increasing number of clinical trials are currently active for LGMD. Examples of recent studies include deflazacort in people with LGMD R9 FKRP-related and AAV1 gamma-sarcoglycan gene therapy for people with LGMD R5 gamma sarcoglycan-related.

You or your child will likely have a team of healthcare providers to manage LGMD. Experts may include:

• Neurologists.
• Physiatrists.
• Geneticists.
• Orthopedists.
• Physical therapists.
• Occupational therapists.
• Cardiologists.
• Pulmonologists.
• Psychologists.
• Social workers.

Outlook / Prognosis

What is the prognosis for people with limb-girdle muscular dystrophy?

It’s difficult for researchers and healthcare providers to predict the prognosis (outlook) of LGMDs with certainty. Your healthcare team will provide as much insight as possible about what to expect while you’re in their care.

In general, when LGMD begins in childhood, the progression of the condition is usually faster, and it results in more complications. When LGMD begins in adolescence or adulthood, it’s generally not as severe and progresses more slowly.

What is the life expectancy of someone with limb-girdle muscular dystrophy?

The average life expectancy of someone with LGMD depends largely on the subtype and how rapidly it progresses. In general, people with LGMD who develop heart and breathing issues typically have shorter lifespans than people with LGMD who don’t have these complications.

Prevention

Can limb-girdle muscular dystrophy be prevented?

As limb-girdle muscular dystrophy is a genetic condition, there’s nothing you can do currently to prevent it.

If you’re concerned about the risk of passing on LGMD or other genetic conditions before trying to have a biological child, talk to your healthcare provider about genetic counseling.

If you have LGMD, there are steps you can take to try to prevent or delay complications and improve your quality of life, including:

• Eat a healthy diet to prevent malnutrition.
• Drink lots of water to avoid dehydration and constipation.
• Do mild to moderate exercise per your healthcare team’s recommendations.
• Maintain a healthy weight.
• Quit smoking to protect your lungs and heart.
• Stay up to date on vaccines.

Living With

How do I take care of myself or someone with limb-girdle muscular dystrophy?

If you have limb-girdle muscular dystrophy or you’re taking care of someone with it, it’s important to advocate for yourself/them to ensure you/they get the best medical care and as much access to therapy as possible. Advocating for care can help you/them have the best possible quality of life.

You and your family may also want to consider joining a support group to meet others who can relate to your experiences.

When should I see my healthcare provider about limb-girdle muscular dystrophy?

If you have limb-girdle muscular dystrophy, you’ll need to see your team of healthcare providers regularly to receive treatment and monitor your symptoms.

A note from Wockr

Understanding your limb-girdle muscular dystrophy (LGMD)diagnosis can be overwhelming. Your healthcare team will offer a robust management plan that’s unique to your symptoms. It’s important to make sure you’re getting the support you need and stay attentive to your health. Know that your healthcare team will be there to support you and your family.