MDA leads the search for treatments and therapies for distal muscular dystrophy (DD). The Association also provides comprehensive supports and expert clinical care for those living with DD.
In this section, you’ll find up-to-date information about distal muscular dystrophy, as well as many helpful resources. This information has been compiled with input from researchers, physicians and people affected by the disease.
In addition to facts about DD in general, this website contains information about the following seven types:
As you learn more about DD, always remember that you’re not alone. MDA is here for you and your family, standing ready to provide help and hope. There is a place for you in the MDA DD community.
MDA provides support by:
Once you sign up with your local MDA office , you’ll begin receiving MDA’s quarterly Quest  magazine, where you’ll find news about research and health care, helpful products and devices, social and family issues, and more.
In addition, MDA will keep you informed through e-alerts, educational publications and speakers, seminars, videos and newsletters.
Please know that there’s a role for you in the fight against distal muscular dystrophy. The MDA community is strong and dedicated, with opportunities for involvement at all levels, such as:
Please know that there’s an important role for every member of the DD community. We urge you to contact your local MDA office  to learn more.
A DD diagnosis doesn’t mean an end to your hopes and dreams. Changes, challenges and adaptations lay ahead, but also opportunity, fulfillment, joy and hope for a future free of distal muscular dystrophy.
Never forget that MDA is here to help.
The distal dystrophies, or DDs, are caused by many different genetic defects, not all of which are yet known. Also, some of the DDs have been given different names based on various symptoms but may actually be caused by defects in the same gene.
Your own form of DD may or may not fit into one of these categories. Many of these diseases can vary from one person to the next, and in some cases, researchers are still in the process of sorting out what symptoms are linked to particular genetic defects.
This disorder has been linked to chromosome 5 in the same region as the gene that’s defective in limb-girdle MD  type 1A. Symptoms first appear between about 35 and 60 years of age and include weakness of the hands, legs or voice. Difficulty in swallowing may be a feature.
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|Lower leg braces can support muscles weakened by distal MD.|
Finnish muscular dystrophy (also called tibial MD) features weakness starting after age 40 in the lower extremities (particularly the muscles over the tibia, a bone in the lower leg) and progressing slowly to the upper extremities and trunk muscles. Cardiac problems can be a feature. This distal myopathy results from mutations in the protein titin, which plays a role in muscle-fiber structure and force generation.
Finnish muscular dystrophy, which typically only affects people of Finnish descent, can be severe or benign. Those with only one defective gene experience mild weakness of the tibial leg muscles (front of the calf) sometime after age 40. Those with two defective genes have progressive weakness starting in childhood and may lose the ability to walk by age 30.
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This disorder has its onset from childhood to 25 years of age. Weakness is first seen in the leg and neck muscles, and progresses slowly to include upper leg muscles, hands and more neck muscles.
Gowers-Laing distal myopathy results from mutations in the MYH7 gene, which instructs for myosin heavy chain 7, a protein that participates in muscle contraction.
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HIBM1 usually begins between the ages of 25 and 40, first affecting the muscles that lift the front of the foot and the thigh muscles. Other muscles can be affected later. Under the microscope, muscle cells show inclusion bodies, which are abnormal clumps of cellular material; and vacuoles, which are cellular bubbles. The cause is unknown.
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This disorder involves weakness that begins in the lower extremities, especially in the calf muscles. It can progress to other muscles as well. Symptoms usually begin between 15 and 30 years of age.
The genetic defects that cause Miyoshi myopathy are in the gene for the dysferlin protein. Defects in the dysferlin gene also can cause limb-girdle muscular dystrophy  2B, which results in muscle weakness in and around the hips and shoulders. People with the same genetic defect in their dysferlin genes can have either disease, and it isn’t known what determines which pattern of symptoms a person gets.
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Usually found in families of Japanese descent, this DD has symptoms that begin between ages 20 and 40. The anterior lower leg muscles (those in the front of the leg) are typically affected first, but the disease may progress to affect upper arm and leg muscles, and neck muscles. The quadriceps muscles (in the thigh) tend to remain strong.
The disease is caused by defects in the GNE gene, the same gene that underlies one form of hereditary inclusion body myositis (HIBM2). (This condition also is called inclusion-body myopathy.)
The GNE protein that comes from this gene modifies compounds on cell surfaces in a way that’s needed for cells to signal each other and adhere to each other.
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This form of distal muscular dystrophy usually has an onset between 40 and 50 years of age. Upper extremities tend to be affected first, then lower ones. The degree of muscle weakness involved can range from mild to severe. The cause remains unknown.
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Typically, the first symptom of distal muscular dystrophy (DD) is weakness in the distal muscles — those farthest away from the hips and shoulders such as those in the hands, feet, lower arms or lower legs. With time, other muscle groups may become affected as well.
Intellect isn’t affected in this disease.
Although most forms of distal muscular dystrophy  are progressive, age of onset and rate of progression can vary widely from one type to the next.
In most cases, muscle mass in the affected regions may become visibly wasted (decreased in size). In some cases, arms, leg or trunk muscles may weaken to the point where mobility and range of motion are limited.
Some forms of distal muscular dystrophy affect the muscles used for speaking or swallowing, and others may affect the heart.
In diagnosing any form of muscular dystrophy, a doctor usually begins by taking a patient and family history and performing a physical examination. Much can be learned from these, including the pattern of weakness. The history and physical go a long way toward making the diagnosis, even before any complicated diagnostic tests are done.
The doctor also wants to determine whether the patient’s weakness results from a problem in the muscles themselves or in the nerves that control them. Problems with muscle-controlling nerves, or motor nerves, originating in the spinal cord and reaching out to all the muscles, can cause weakness that looks like a muscle problem but really isn’t.
Usually, the origin of the weakness can be pinpointed by a physical exam. Occasionally, special tests called nerve conduction studies and electromyography (EMG)  are done. In these tests, electricity and very fine pins are used to stimulate and assess the muscles or nerves individually to see where the problem lies. Electromyography is uncomfortable but not usually very painful.
Early in the diagnostic process doctors often order a special blood test called a CK level . CK stands for creatine kinase, an enzyme that leaks out of damaged muscle. When elevated CK levels are found in a blood sample, it usually means muscle is being destroyed by some abnormal process, such as a muscular dystrophy or inflammation. Therefore, a high CK level often suggests that the muscles themselves are the likely cause of the weakness, but it doesn’t tell exactly what the muscle disorder might be.
To determine which disorder is causing CK elevation, a doctor may order a muscle biopsy , the surgical removal of a small sample of muscle from the patient. By examining this sample, doctors can tell a great deal about what’s actually happening inside the muscles. Modern techniques can use the biopsy to distinguish muscular dystrophies from infections, inflammatory disorders and other problems.
Other tests on the biopsy sample can provide information about which muscle proteins are present in the muscle cells, and whether they’re present in the normal amounts and in the right locations. This can reveal what’s wrong with the cells’ proteins and provide likely candidates as to which genes are responsible for the problem. The correlation between missing proteins on the muscle biopsy and genetic flaws isn’t perfect, however. An MDA clinic  physician can help you understand these results.
Genetic (DNA) tests, using a blood sample, can analyze the person’s genes for particular defects that cause DD, help predict the likely course of a disease and help families assess the risk of passing on the disease to the next generation. For more on genetic patterns in DD, see Causes/Inheritance . And, for more on getting a definitive genetic diagnosis, see The Genie's Out of the Bottle: Genetic testing in the 21st century .
All the forms of muscular dystrophy are inherited — that is, they’re caused by mutations (changes) in a person’s genes. Our genes are made of DNA and reside in our chromosomes. Each gene contains the “recipe” for a different protein and its variations, and these proteins are necessary for our bodies to function correctly.
When a gene has a mutation, it may make a defective protein or none at all. Most commonly, missing or defective proteins in the muscles prevent muscle cells from working properly, leading to symptoms of muscular dystrophy, including muscle weakness and wasting over time.
The different types of DD  are caused by many genetic defects, not all of which are yet known. Some of the DDs have been given different names based on various symptoms but actually may be caused by defects on the same gene.
Most forms of DD are inherited in an autosomal dominant pattern, but some follow a recessive pattern of inheritance.
In brief, if a disease is recessive, two copies of the defective gene (one from each parent) are required to produce the disease. Each parent would be a carrier of the gene flaw, but wouldn’t usually have the disease.
If a disease is dominant, then only one copy of the genetic defect is needed to cause the disease. Anyone with the gene flaw will have disease symptoms and can pass the disorder to children.
Many times muscular dystrophy appears to have occurred “out of the blue,” but in reality, one or both parents may be carriers, silently harboring the genetic mutation. Often parents have no idea they’re carriers of a disease until they have a child who has the disease.
A good way to find out more about these risks is to talk to your MDA clinic  physician or ask to see the genetic counselor at the MDA clinic. For more, see Facts About Genetics and Neuromuscular Diseases .
|Classification of Distal Muscular Dystrophies|
|Types of DD||Cause||Inheritance Pattern|
|Welander distal myopathy||abnormalities in chromosome 2 gene||dominant|
|Finnish (tibial) distal myopathy||titin abnormalities||dominant|
|Miyoshi distal myopathy||dysferlin abnormalities||recessive|
|Nonaka distal myopathy; also called hereditary inclusion-body myositis type 2 (HIBM2)||GNE abnormalities||recessive|
|Gowers-Laing distal myopathy||MYH7 abnormalities||dominant|
|Hereditary inclusion-body myositis type 1 (HIBM1)||unknown||dominant|
|Distal myopathy with vocal cord and pharyngeal weakness||abnormalities in chromosome 5 gene||dominant|
|Source: Washington University Neuromuscular Home Page, May 2006|
Forearm and hand weakness
Your MDA clinic  can refer you to an occupational therapist who can help you get the most out of your hand and forearm muscles in performing day-to-day activities. Often, the therapist can recommend devices that may improve grip strength or help support your arms for using a keyboard or eating.
Lower leg and foot weakness
Weakness of the lower leg and foot muscles can make walking difficult. In some cases, an ankle-foot orthosis (AFO), a brace worn over the shoe and lower leg, can help.
AFOs are especially useful when muscles in the front of the lower leg aren’t strong enough to pick up the front of the foot during walking. In this condition, known as foot drop, an AFO can prevent the foot from flopping down and tripping the person.
Swallowing and heart problems
Some forms of distal muscular dystrophy affect the muscles used for swallowing, and precautions must be taken when eating or drinking so that food isn’t aspirated into the lungs.
Other forms of DD  affect the heart, and special precautions must be taken to monitor heart function. Each disorder has its own special areas of concern.
In 1992, at the age of 32, I was diagnosed with inclusion-body myositis (IBM) . About six years later, my youngest sister Celeste learned she also has IBM, which gave us both a diagnosis of hereditary inclusion-body myositis, or HIBM  — the kind of IBM that runs in families. MDA classifies HIBM as a distal muscular dystrophy.
Through the years, adaptations have been made to accommodate the changes to my body due to the disease. For example, ankle-foot orthotic braces help me tremendously. After 20 years of wearing them, I am still capable of standing and moving around. As my disease symptoms have progressed, I’ve come to view my power wheelchair as a remarkable asset. It takes me almost anywhere I want to go, including sea cruises, which have been wonderful experiences.
I keep myself so busy that lately my biggest problem has been finding the time. My former career was in the furniture/kitchen manufacturing business. Woodworking was my life. Sadly, I had to retire due to my disability. But I never really stopped working. I went forward with a business called The Cookie Nook. I came up with the idea, wrote a business plan, and a year later we were baking cookies and delivering them nationally. It was a lot of fun, but my love of sawdust was still there. So, eventually, I sold the cookie business.
A power tool called a scroll saw was my door back into woodworking. A small tabletop machine, it gives me the ability to create intricate items made from exotic hardwoods. Scrolling allows me to express my creativity while sitting down; it’s something I truly enjoy doing. Thus began my second post-diagnosis business, Wood Crafts by Chris .
Shortly after my diagnosis, I became involved with the Muscular Dystrophy Association, and it’s become a big part of my life. The staff is wonderful, very helpful in every aspect and the doctors are top notch. They really care about each and every one of us. MDA and all its resources are there to help you and your family. My sister Celeste is also an active member of the MDA family. Together we have been involved in case studies and experimental treatments: positive research with promising results.
While MDA’s research program continues making strides toward better treatments and a cure, it’s also good to know that people with disabilities have more opportunities than ever before to develop and use their abilities, and that the laws entitle us to equal employment opportunities and access to public places.
I hope that hearing my story will provide you and your loved ones with some encouragement about life with muscle disease. And always remember, you’re not alone!
Boynton Beach, Florida
First described in 1902, DD is a class of muscular dystrophies that primarily affect distal muscles, which are those of the lower arms, hands, lower legs and feet. Muscular dystrophies in general are a group of genetic, degenerative diseases primarily affecting voluntary muscles.
Types of distal muscular dystrophy  include: distal myopathy with vocal cord and pharyngeal weakness; Finnish (tibial) distal myopathy; Gowers-Laing distal myopathy; hereditary inclusion-body myositis type 1; Miyoshi distal myopathy; Nonaka distal myopathy; Welander’s distal myopathy; and ZASP-related myopathy.
Distal muscular dystrophy can lead to weakness and wasting of muscles of the hands, forearms and lower legs. For more, see Signs and Symptoms .
DD is caused by a mutation in any of at least eight genes that affect proteins necessary to the function of muscles. It can be inherited in an autosomal dominant or recessive pattern. For more, see Causes/Inheritance .
DD begins in either childhood or adulthood, and is slowly progressive. It doesn't affect the intellect and is not considered life-threatening.
Recent MDA-supported research in distal muscular dystrophy  has concentrated on understanding how the gene defects that cause this diverse group of diseases affect the proteins made from these genes, and in turn how these protein abnormalities affect muscle tissue.
Recent MDA-supported research in distal muscular dystrophy (DD) has concentrated on understanding how the gene defects that cause this diverse group of diseases affect the proteins made from these genes, and in turn how these protein abnormalities affect muscle tissue.
When the protein and tissue abnormalities are understood, it is hoped, potential avenues of treatment will reveal themselves.
Abnormalities in the dysferlin protein, which underlie many cases of DD, have received particular attention. It's been found that dysferlin loss may lead to muscular dystrophy by making muscles less able to repair themselves when they're damaged.
Some researchers are working on developing gene replacement therapy for dysferlin-related DD, while others are trying to identify other ways to compensate for dysferlin's loss or malfunction.
Other cases of DD are caused by mutations in the gene for the titin protein. The muscle abnormalities caused by these mutations have also received particular attention from MDA-supported researchers.
A clinical trial is a test in humans of an experimental medication or therapy. Clinical trials are experiments, not treatments, and participation requires careful consideration.
Although it's possible to benefit from participating in a clinical trial, it's also possible that no benefit — or even harm — may occur. Keep your MDA clinic  doctor informed about any clinical trial participation. (Note that MDA has no ability to influence who is chosen to participate in a clinical trial.)
For more about clinical trials in general, see Learn About Clinical Studies , and to learn more about trial participation in neuromuscular disease, read the Quest magazine article Being a Co-Adventurer .
For a more refined list of DD clinical trials, visit ClinicalTrials.gov , a registry of federally and privately supported clinical trials in the United States and around the world. Select "Search for Clinical Trials," and follow the instructions to narrow down your search results.