Limb-Girdle Muscular Dystrophy (LGMD)

A diagnosis of muscular dystrophy in any form often causes shock, whether it's you or a loved one who's sick.

At a time like this, you need information from a source you can trust, that's why at YourDNA.com, we've put together this report with the information you need in a form and language you can understand.

It's a place to get your questions answered and get the facts you need to talk to your medical team moving forward.

What Is Limb-Girdle Muscular Dystrophy?

Limb-girdle muscular dystrophy (LGMD) is a rare disease that causes weakness and deterioration in the arm and leg muscles. 

Like other neuromuscular disorders, limb-girdle muscular dystrophy mostly affects the muscles closest to the body, including the upper arms, thighs, pelvic muscles, and shoulders ¹.

When this muscular dystrophy type first presents itself, you might feel like your arms and/or legs are getting weaker.

This feeling continues to worsen over time, and eventually, those with limb-girdle muscular dystrophy may require a wheelchair to remain mobile. 

There are 19 different forms of limb-Girdle muscular dystrophy ², each of which is classified by the genetic flaws that cause the disease.

There are 15 different genes responsible for the production of muscle proteins that have been identified to cause LGMD when they are flawed.

Causes of Limb-Girdle Muscular Dystrophy 

Limb-girdle muscular dystrophy is caused by mutations in one or several of 15 different genes.

The genes affected are the ones responsible for providing instructions for making the proteins that are involved in the muscle repair and maintenance process.

This includes the FKRP gene, which is in charge of making fukutin-related protein.

When these gene mutations are inherited from parents, their offspring could have limb-girdle muscular dystrophy.

Keep in mind, parents don’t have to have the disease for their children to get it. If they are both carriers of the mutated genes, children have a chance of getting limb-girdle muscular dystrophy even if they don’t have it.

The Genetic Pattern of Inheritance of Limb-Girdle Muscular Dystrophy

It’s common for people with limb-girdle muscular dystrophy to wonder how they inherited the disease when it doesn’t seem to run in their family.

However, even if only one biological relative has limb-girdle it’s still possible to get it because of the way genetic diseases are inherited.

Limb-girdle muscular dystrophy can be inherited in one of two ways: an autosomal dominant pattern or an autosomal recessive pattern.

Autosomal means that the gene isn’t on the X or Y chromosome, which means both men and women have the same risk of inheriting the disease.

When limb-girdle muscular dystrophy is inherited through a dominant pattern, it means that the parent has limb-girdle muscular dystrophy and has passed the flawed gene down to the child, who is also experiencing symptoms of the disease.

If the disease was inherited through an autosomal recessive pattern, the child’s parents don’t actually have the disease.

Instead, they were both carriers of the flawed gene that caused the child to have LGMD and they each passed down that flawed gene to the child. 

For example, if a child inherits limb-girdle muscular dystrophy with a titin gene mutation and his or her parents don’t have it, this means both parents actually have one flaw gene and one good gene.

This prevents them from actually having the disease. Because the child received the flawed gene from both parents, he or she has the disease.

If both parents are carriers of the flawed gene, the child has a 25% chance of inheriting the disease.

Who Gets Limb-Girdle Muscular Dystrophy? 

The limb-girdle muscular dystrophy prevalence is unknown, but estimates range from one in every 14,500 people to one in every 123,000 people ³. 

Also, both men and women have the same risk of getting limb-girdle muscular dystrophy — the disease doesn’t favor one gender over the other.

Risk Factors for Limb-Girdle Muscular Dystrophy

Like many forms of muscular dystrophy, LGMD affects both men and women equally. However, people with a family history of the disease are at a high risk of developing the disease or passing it onto their children. 

This is different than Duchenne muscular dystrophy, for example, which affects young boys more than young girls.

Even though both men and women are equally at risk for limb-girdle muscular dystrophy, there are some types of the disease that affect specific races more than others.

For example, limb-girdle muscular dystrophy 2B is more likely to affect Jewish people or those of Libyan-Jewish descent than people of other races.

Signs & Symptoms of Limb-Girdle Muscular Dystrophy

Limb-girdle muscular dystrophies affect the muscles around the shoulder girdle and hips. The disease progresses over time, and often, those with LGMD begin to show signs of the disease in their late childhood to early teen years. 

Typically, the first sign of limb-girdle muscular dystrophy is pelvic muscle weakness.

As this presents itself, you might notice your child has difficulty moving from sitting to a standing position without using his or her arms, or he or she might find it difficult to climb stairs. 

Other signs and symptoms of limb-girdle muscular dystrophy include:

• Abnormal walking, sometimes waddling
• Large, muscular-looking calf muscles that aren’t actually strong
• Lower back pain
• Thinning of the arms and legs as muscle mass begins to fade
• Heart palpitations
• Spells of passing out
• Shoulder weakness

As the disease progresses, these signs and symptoms might occur:

1. Muscle weakness in the face
2. Muscle weakness in the lower legs, lower arms, hands, and feet
3. Joints fixed in a contracted position

Diagnosis of Limb-Girdle Muscular Dystrophy

The age of onset for limb-girdle muscular dystrophy varies, but it’s common for signs and symptoms to begin presenting themselves during the late-childhood or early-teen years.

If you believe your child has LGMD, there are several tests your doctor can complete to verify or rule out the diagnosis, including ⁴:

1. Muscle biopsy
2. Blood creatine kinase levels
3. DNA testing — specifically, molecular genetic testing
4. Echocardiogram (ECG)
5. Electromyogram (EMG)

Are There Prenatal Tests for Limb-Girdle Muscular Dystrophy?

If you’re wondering, “can muscular dystrophy be detected during pregnancy?” You’ll be relieved to know the answer is yes. 

There are two types of prenatal tests that detect muscular dystrophy ⁵. After 11 weeks of pregnancy, chorionic villus sampling (CVS) can be completed to determine whether the baby has limb-girdle muscular dystrophy or another for of myopathy.

This test involves removing tissue from the placenta for analysis. Also, an amniocentesis test can be performed between 16 and 20 weeks of gestation to see if the baby has the disease.

Typically, these tests are only completed if the mother is a known carrier of one of the mutated genes known to cause LGMD, one of the parents has the disease, or another child in the family was born with it.

If you’re worried you might be a carrier of limb-girdle muscular dystrophy or any inflammatory myopathies, a simple DNA test can confirm or deny this.

Carrier Screening for Limb-Girdle Muscular Dystrophy

If there’s a history of limb-girdle muscular dystrophy in your family, you can be screened to see if you’re a carrier of any of the flawed genes. To get tested, you need to discuss the possibility with your doctor. 

The DNA test is performed via a simple blood test. After the blood is drawn, your doctor tells the lab which genes to analyze and then, once the test is complete, you’re contacted with the results.

What Is the Risk of Passing the Condition on to My Children?

The risk of passing limb-girdle muscular dystrophy on to your children is the same as passing on any other genetic condition.

To have limb-girdle muscular dystrophy, you have to have two of the same flawed genes that cause the disease. 

So if you have LGMD and your partner is a carrier of the flawed gene, there's a 50% chance of passing the disease on to your children.

If you and your partner are both carriers of the same flawed gene, you have a 25% chance of having a child with the disease and a 50% chance your child will be a carrier of the disease. 

Keep in mind, the child would have to have two of the same flawed genes to actually have the disease and children receive one of each gene from each of their parents.

So if only one parent is a carrier, there is no chance the child will have limb-girdle muscular dystrophy. However, there’s a 50% chance your child will be a carrier of the disease. 

Limb-Girdle Muscular Dystrophy and Pregnancy

Getting pregnant with muscular dystrophy is possible, but in some cases, it’s not recommended. If your muscular dystrophy affects your heart, for example, pregnancy should be avoided.

Of course, limb-girdle muscular dystrophy in babies, which is the main concern for many women, is possible through a muscular dystrophy carrier pregnancy.

However, the risks are higher when one parent actually has the disease. 

If you have LGMD and you become pregnant, it’s important to discuss all of your options with your doctor.

Because the disease affects the muscles in your pelvic area, including those surrounding your uterus, there’s a good chance you’ll have to deliver the baby via C-section.

Treatments and Care Options for Limb-Girdle Muscular Dystrophy

Unfortunately, there isn’t a cure for LGMD. Instead, limb-girdle muscular dystrophy specialists focus on treating and managing the symptoms of the disease.

Some treatment options include:

• Weight management to avoid obesity, which makes it harder for you to remain mobile
• Physical therapy and stretching exercises to prevent your muscles from tightening and promote mobility
• Monitoring respiratory function and if it declines, the use of respiratory aids
• Monitoring the potential of developing swallowing issues, and if needed, the use of nutritional supplements
• Using mechanical aids such as walkers, canes, and wheelchairs
• Monitoring your heart for evidence of cardiomyopathy
• Social and emotional support to reduce the possibility of social isolation
• Surgical procedures if needed, to correct orthopedic conditions such as scoliosis or foot deformities

Medical researchers are also involved with clinical trials, some of which involve the use of stem cells, to try new methods of treating people with limb-girdle muscular dystrophy.

If you want to participate in these trials, you should discuss your options with your doctor.

Complications Associated With Limb-Girdle Muscular Dystrophy

Limb-girdle muscular dystrophy is a progressive disease that normally only affects the muscles in the shoulder girdle and pelvic area. 

However, it is possible for the disease to spread to other areas of the body.

In extreme cases, it’s possible for LGMD to affect the heart and the respiratory system. It can also cause complications with swallowing.

Additionally, as the disease progresses, those living it may need to use a walker or cane to get around.

Or if the disease is advanced, mobility may not be possible without a wheelchair.

The Prognosis of Limb-Girdle Muscular Dystrophy

Limb-girdle muscular dystrophy is a progressive disease that typically begins in late childhood. In most cases, symptoms present themselves between the ages of eight and 15, but some forms of limb-girdle muscular dystrophy might show up in children as young as two years old and adults as old as 40. 

In most cases, the disease progresses fairly rapidly through the beginning of the teenage years.

However, while other forms of muscular dystrophy have average lifespans in the late teens and early 20s, the limb-girdle muscular dystrophy lifespan isn’t a major concern.

Unless the disease spreads to the heart or respiratory system, people don’t usually die from LGMD. 

What to Do Next: Living With Limb-Girdle Muscular Dystrophy

Depending on how severe your symptoms are living with limb-girdle muscular dystrophy can be difficult. It’s important to continue your physical therapy sessions because they are designed to promote mobility and keep your muscles from stiffening. 

Your doctor will also monitor your heart and respiratory systems to ensure the disease doesn’t spread to vital organs.

Also, you should consider having your doctor keep you up to date on any new LGMD research in case a promising clinical trial becomes available.

You can also keep up with new research and medical advancements by following the Muscular Dystrophy Association (MDA) online.

They share news for all types of muscular dystrophy, including LGMD.

They can also get you in contact with support groups that can help ease the burden as you learn from and help other patients and caregivers.

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