A group of rare muscular dystrophies that negatively affect the muscles in the shoulders, upper arms, hips, and upper legs is called limb-girdle muscular dystrophy (LGMD). Moreover, this condition has multiple subtypes based on which gene mutates. This condition cannot be cured, and the treatment goal is to relieve the symptoms, prevent life-threatening complications, and improve your quality of life.
The name of this condition comes from certain bony structures localized around the shoulder and pelvic area (limb girdles). People with this LGMD have problems with muscles that are near these bony structures. Generally, muscular dystrophy is a type of group of genetic disorders that negatively affect the function of muscles. Most of the time, the symptoms worsen over time.
LGMD occurs quite rarely, and it affects about 2 in 100,000 people in the U.S. However, the most common form of muscular dystrophy in the U.S. is Duchenne muscular dystrophy, which affects about 1 in 3,600 people. One of the most common subtypes of LGMD is R1 calpain3-related (calpainopathy). It accounts for about 15% to 30% of all diagnosed LGMD cases.
What Are The Symptoms of LGMD?
The primary symptom of this condition is muscle weakness and atrophy that often affects the shoulders, upper arms, hips, and upper legs. Moreover, the severity of the symptoms depends on which subtype you develop and the age at which the symptoms appear. Commonly, the first sign of LGMD is walking problems. However, some people may also experience a waddling gait and difficulty standing from a seated position or climbing stairs. It may also cause problems with:
- Feeding yourself
- Lifting heavy objects
- Holding the arms outstretched
- Reaching over the head
Additionally, there are some subtypes of LGMD that may cause additional health problems. Check some examples below:
- Muscle weakness that affects other parts of the body (including the hands and feet)
- Joint stiffness
- Dysphagia (swallowing problems)
- Trouble breathing
- Hypertrophy (enlarged calf muscles)
- Heart problems (including arrhythmia, cardiomyopathy, and conduction abnormalities)
- Muscle cramps
If you experience any of the previous symptoms, immediately contact your healthcare professional. Leaving this condition untreated may lead to serious complications.
What Are The Potential Complications of LGMD?
Those who develop this muscular dystrophy may also experience some complications, especially if the condition is poorly managed. It often depends on the condition’s subtype, the age of onset, and how quickly you get treatment. Check some complications below:
- Developmental delays
- Intellectual disability (including learning problems)
- Kyphosis
- Scoliosis
- Malnutrition that is usually caused by problems with swallowing or eating
- Lung diseases that, without treatment, may lead to respiratory insufficiency or even failure
- Progressive weakness of the heart muscle
This document does not contain a full list of complications, but you can talk with your physician about ways to reduce the risk or even prevent them. For example, stop smoking, avoid alcoholic beverages, drink plenty of water to prevent dehydration, adopt a healthy diet, maintain a healthy weight, and stay up to date on vaccines. Unfortunately, there is no way to prevent this condition because doctors do not fully understand what exactly causes it.
Causes
LGMD occurs due to a genetic mutation that may pass from biological parents to their children during pregnancy. Nowadays, experts do not know what exactly causes these genetic changes (mutations). Normally, these genes are responsible for healthy muscle structure and function. Moreover, there are two major groups of LGMD, based on how you inherit the abnormal genes. For example:
- LGMD D group – This type occurs due to autosomal dominant inheritance patterns, which means getting even one abnormal gene is enough to develop LGMD.
- LGMD R group – In this case, the disorder happens due to an autosomal recessive inheritance pattern, which means you have inherited the abnormal gene from both biological parents.
Subtypes of LGMD
Autosomal Dominant Subtypes
These include:
- LGMD D1 DNAJB6-related
- LGMD D2 TNP03-related
- LGMD D3 HNRNPDL-related
Autosomal Recessive Subtypes
In general, there are multiple forms of autosomal recessive inheritance patterns. Check some of them below:
- R1 calpain3-related
- R3 sarcoglycan-related
- R7 telethonin-related
- R9 FKRP-related
- R10 titin-related
- R12 anoctamin5-related and others
Diagnosis
Most of the time, when doctors suspect LGMD, they start the diagnosis with a physical and neurological examination. However, to confirm or rule out LGMD, doctors will perform the following tests and procedures. Examples include:
- Creatine kinase blood test – Typically, damaged muscles release creatine kinase in the blood. Increased levels of this substance often indicate muscular dystrophy.
- Genetic tests – This test requires a blood sample to check for abnormal genes that cause LGMD.
- Muscle biopsy – During this procedure, physicians will take a sample of affected muscle for testing.
- Electromyography (EMG) – This test is often performed by doctors to measure the electrical activity of the muscles and nerves.
Sometimes, doctors may also recommend heart and lung function tests.
Treatment
This condition cannot be cured, and the treatment goal is to relieve the symptoms, prevent serious complications, and improve your quality of life. Check below some options often recommended by doctors for people with LGMD:
- Occupational and physical therapy – Doctors recommend these therapies to strengthen the muscles and maintain movement function.
- Corticosteroids – This group of medications is used to improve muscle weakness, lung function, and delay scoliosis. Typically, they are used to reduce inflammation. Doctors often recommend Prednisolone or Deflazacort.
- Mobility aids – These include canes, braces, walkers, and wheelchairs.
- Surgery – In some cases, doctors may recommend surgery to relieve tension on contracted muscles and treat scoliosis.
- Assisted ventilation and tracheostomy (these options are used to treat respiratory failure)
- ACE inhibitors, beta-blockers, or pacemakers – These treatments are used to treat heart issues that may occur in people with LGMD.
- Speech therapy – This treatment is used to improve language issues and dysphagia.
Commonly, to treat this condition, people require a healthcare team. These include neurologists, physiatrists, geneticists, physical therapists, orthopedists, cardiologists, pulmonologists, psychologists, and others.
Frequently Asked Questions
Is limb-girdle muscular dystrophy (LGMD) inherited?
Yes. LGMD is a genetic disorder that is usually inherited from one or both biological parents. Depending on the subtype, it follows either an autosomal dominant or autosomal recessive inheritance pattern. In rare cases, a new (spontaneous) genetic mutation may occur without a family history.
At what age do symptoms of LGMD usually begin?
Symptoms can begin at almost any age, from early childhood to adulthood. The age of onset depends on the specific genetic subtype. Generally, people who develop symptoms earlier in life may experience faster disease progression than those whose symptoms begin later.
Can people with LGMD walk throughout their lives?
It depends on the subtype and severity of the disease. Some people remain able to walk for decades with mild weakness, while others may eventually require mobility aids such as braces, walkers, or wheelchairs. Early rehabilitation and regular medical care may help maintain mobility for longer.
Does LGMD affect life expectancy?
Some people with mild forms of LGMD have a near-normal life expectancy. However, certain subtypes can lead to serious heart or breathing complications that may shorten lifespan if they are not properly monitored and treated. Regular cardiac and respiratory evaluations are an important part of long-term care.
Is exercise safe for people with LGMD?
Yes, but it should be done under medical supervision. Low-impact activities such as swimming, stretching, and gentle strengthening exercises may help maintain muscle function and flexibility. High-intensity or strenuous exercise should be avoided because it can increase muscle damage in some people.
Can LGMD affect the heart and lungs?
Yes. Some subtypes of LGMD can weaken the heart muscle, cause abnormal heart rhythms, or affect the muscles involved in breathing. Routine heart tests, lung function tests, and follow-up appointments are important for detecting and treating these complications early.
How is LGMD different from Duchenne muscular dystrophy?
Although both are forms of muscular dystrophy, they are caused by different genetic mutations. Duchenne muscular dystrophy usually begins in early childhood, primarily affects boys, and progresses rapidly. LGMD includes many different subtypes, can affect both males and females, and has a much wider range of ages of onset and disease severity.
Can genetic testing confirm LGMD?
Yes. Genetic testing is considered the most accurate way to identify the specific gene mutation responsible for LGMD in many cases. Confirming the subtype helps guide treatment decisions, monitor for possible complications, and provide genetic counseling for family members.
Is there ongoing research for new LGMD treatments?
Researchers are actively studying gene therapy, stem cell therapy, and other targeted treatments for several LGMD subtypes. While these therapies are not yet widely available, clinical trials continue to improve the understanding and treatment of this group of disorders.
When should someone with LGMD seek immediate medical attention?
People with LGMD should seek prompt medical care if they experience severe shortness of breath, chest pain, fainting, difficulty swallowing that leads to choking, repeated lung infections, or sudden worsening of muscle weakness. These symptoms may indicate serious complications that require urgent evaluation and treatment. Ask your healthcare professional if you have any other questions.
