An inherited disease that causes increasing weakness in muscle tissue. If this happens in skeletal muscles as normal, it can be dehabilitating. If it happens in the heart, it's time to start day trading. MD usually happens in cycles of degeneration and regeneration of tissue, with the muscle tissue becomming more and more composed of scar tissue and fat as prime flesh is degraded away.

Muscular dystrophy comes in a few flavors, but the most common is Duchenne's Muscular Dystrophy. It occurs once every 3,300 male births, and since it's on the X-chromosome, it strikes males almost exclusively. Symptoms begin to show after the first birthday: A child will start to walk with an abnormal gait, and has trouble getting up and lifting his knees, which prevents running. At the age of five, the calves are larger, and there is little or no knee-jerk reaction. Stairs become impossible, and by the time the boy reaches his teens, he can no longer walk. The disease spreads from the legs to the arms, then to the trunk, affecting respiration and the heart. Sufferers of Duchenne's rarely live to see 20.

There is currently no cure for the disease, although there are numerous treatments that include surgery, physical therapy, splints, and braces.

Thanks a lot to for the info

A family of disorders, some of which are fatal, some not. All involve the progressive weakening and wasting of muscle tissue; this process is not painful by itself, but can have side-effects which are painful. There's no cure, and patients don't recover muscle they've lost. The disorder is due to irregular or absent production of the protein dystrophin, which is required for healthy muscles. Depending on the form of MD one has, the symptoms can appear early or late in life, and can cause anything from mild inconvenience to severe disability and death.

The poster children for the Muscular Dystrophy Association (MDA) often have the more severe forms of MD. Since most people's image of the diseases comes from "Jerry's kids", most people think of MD as a death sentence or a ticket to a life that's unimaginably impaired; this picture is not entirely accurate. Some forms of MD do cause very severe disability and early death; death usually happens because the heart or lung muscles are affected. But many people with MD are quite mobile and lead pretty normal lives, with some degree of increase in daily engineering challenges. Most forms of MD don't affect mental function at all, although they may cause slurring of speech which is sometimes incorrectly interpreted as a sign of diminished mental capacity.

Muscular dystrophies are genetic; they are not contagious or a result of bad parenting. There may be environmental triggers for some forms of MD; in rare cases, a random genetic mutation can cause a child to develop MD even if its parents don't have the gene for MD. Scientists have identified the inheritance characteristics of most forms of MD, and in some cases, have identified a gene or genes which are thought to be responsible.

Muscular Dystrophies-- I've tried to include information on age of onset, primary effects, severity, incidence, and genetic profile. If the info isn't here, I couldn't find it. If there's no number given for the incidence, assume that the disorder is rare. These are in alphabetical order, except that Duchenne's is first.

Duchenne Muscular Dystrophy
(Also known as Pseudohypertrophic) --- Onset in early childhood, progresses slowly but affects all voluntary muscles including the lungs, generally fatal by 20s. It is inheritable, an x-linked recessive trait so it nearly always affects males. The involved gene has been identified, and in utero genetic tests for Duchenne's are very accurate. This is the most severe, and also one of the two most common forms of MD, striking about 1 in 4000 boys in the US.

Becker Muscular Dystrophy
Similar to Duchenne's but less severe. Onset in teens or 20s, progresses slowly but affects all voluntary muscles including the lungs, survival into 40s. It is an x-linked recessive trait so it nearly always affects males; the involved gene has been identified and there is an in utero test for it. It strikes about 1 in 25,000 in the US.

Congenital Muscular Dystrophy
Onset at birth. Weakens all muscles, may cause joint deformities. Fukuyama form is more severe and involves mental functions. Different forms have different inheritance characteristics; the involved gene has been identified for one form.

Distal Muscular Dystrophy
(Also Miyoshi) -- Onset in middle age. Affects muscles of hands, forearms, and lower legs. Slow progression, not life-threatening. It is autosomal dominant, so affects males and females equally.

Emery-Dreifuss Muscular Dystrophy
Onset in childhood or early teens, affects shoulder, upper arm, shin and heart muscles, may cause joint deformities. It is an x-linked recessive trait; the involved gene has been identified.

Facioscapulohumeral Muscular Dystrophy
(Also known as Landouzy-Dejerine) -- Onset from childhood to early adulthood. Affects facial muscles, upper arms and shoulders. Progresses slowly with periods of rapid deterioration; although much less severe than most forms of MD, it is tremendously variable in its degree of severity. Not life-threatening. It is autosomal dominant, so affects males and females equally. 1 out of 20,000 people have it.

Limb-Girdle Muscular Dystrophy
Onset anywhere from late childhood to middle age, affects the shoulder and pelvic girdles. There are at least 12 different forms, which differ in their genetic characteristics; involved genes have been identified for only some of these.

Myotonic Dystrophy
(Also known as Steinert's Disease) -- Onset anywhere from birth to middle age. Affects face, feet, hands and neck first, causing delayed relaxation of muscles after contraction (eg, inability to release grip on an object). Slow progression can span 60 years. It is autosomal dominant so affects males and females equally; the involved gene has been identified. Affecting 1 in 8000 people, it is the one of the two most common MDs.

Oculopharyngeal Muscular Dystrophy
Onset in early 20s to middle age. Affects muscles of eyelids and throat, swallowing problems commonplace as disease progresses. It is autosomal dominant, so affects males and females equally.


Other disorders that aren't muscular dystrophies, but are commonly confused with MD. All affect motor control, but they do so by affecting the nervous system's ability to control muscles; they don't attack the muscles themselves:

ALS -- Lou Gehrig's disease -- This is what Stephen Hawking has.
MS -- Multiple Sclerosis
Myasthenia Gravis
Parkinson's Disease
Cerebral Palsy

Primary source of profiles of the different MDs:; some material in the profiles is quoted directly. The web sites of the Muscular Dystrophy Association (MDA) are the best starting place for more information; they have different sites in different countries.

Duchenne Muscular Dystrophy

Definition/History It is the most fatal of all the muscular dystrophies; pseudohypertonic muscular dystrophy, widely known as Duchenne muscular dystrophy. Affecting only boys, Duchenne is a result of the absence of the protein dystrophin in muscle fibres. This absence causes muscles to weaken and wither away.

In the 1850s and 1860s, a French doctor by the name of Guillaume-Benjamin-Amant Duchenne observed patients with the signs and symptoms of muscular dystrophy. However, Duchenne did not believe that the problem was within the muscles themselves, but of a nervous system disorder because of the mental retardation of some of his patients. (Muscular dystrophy was not know known to be a muscular disease until a German doctor named Ernst Leyden noticed that the symptoms were much different than those of obvious nervous system problems.)

Duchenne’s research was done with a harpoon-like device called a “trochar”, which he invented himself. It is a hollow needle that was to be pushed through the skin into the muscle. The needle would then be taken out, extracting bits of muscle in the process. This today is known as a muscle biopsy.

Causes Duchenne is a disease, which can only be inherited. The mother is usually the one who carries a defective gene, since males with Duchenne rarely become fathers. This occurrence protects females from inheriting the defective gene. The chance of a boy receiving the X chromosome with the defective gene is fifty percent.

The gene that causes Duchenne muscular dystrophy is ten times larger than any human gene found to this day and five hundred times larger than the average size gene. Because of its large size, it is more susceptible to damage. People who have the disease have large sections of it missing or alterations in the gene.

Dystrophin, the protein found in normal muscle fibres, is absent within the muscles of a child suffering from DMD. Without dystrophin, the outer membrane of a muscle cell will begin to leak. This may begin the buildup of electrically charged calcium particles that enter through the leaky membrane. It is probable that this calcium buildup activates a protein that dissolves muscle fibres.

Effects/Symptoms The first signs of DMD may begin in the womb, but are usually manifested between the ages of one and three years old. Typically, by the time a boy is able to walk he will have an abnormal waddling gait. He will have trouble getting up and climbing stairs. As he becomes older, his posture will change, with an arched back, and stomach thrusting forward. This position actually allows for balance among the weakened muscles.

The first muscles to be affected are in the upper arms and legs, and hips. Those muscles shrink in size, but oddly enough, the calf muscles will enlarge. The reason for this enlargement is due to the replacement of the dying muscle fibres with fat and connective tissues. By the age of ten (or, in some cases, a couple of years earlier) a boy with Duchenne will be confined to a wheelchair. His joints in the ankles and elbows will pull into awkward positions dues to the shortening of the muscles in the arms and legs.

As the boy reaches his late teens his lung muscles will become affected leading to difficulty in breathing and the development of lung infections, which are the number one cause of death among DMD sufferers. Occasionally, the heart muscle is affected and heart failure follows.

Diagnosis The initial diagnosis of Duchenne is a simple one. The doctor will learn which muscles were primarily affected, the age of onset of the symptoms, and the severity of those symptoms.

The second step is the electromyography. This monitors the muscle’s electrical activity at rest and during contraction. Small needlelike electrodes are inserted through the skin into selected muscles. When the muscle contracts it shows a sharp decrease in electrical response followed immediately by an increase. The electromyography of a dystrophic muscle is very distinctive. There are many brief muscle contractions and there is little or no time spent in rest.

After the electromyography, a doctor will perform a muscle biopsy. A muscle biopsy is the removal and examination of a small piece of muscle. A muscle affected by DMD will show shrunken cells and the expansion of fatty tissues.

The last test is for the protein dystrophin. As stated before, if there is no dystrophin found in the muscle fibres that person would have Duchenne.

Treatment As of yet, there is no cure for any type of muscular dystrophy. However, treatment does exist.

Physical therapy, exercise, and surgery are all candidates for treatment. The exercise and physical therapy keep the muscle fibres as fit as possible. For children with DMD, swimming is a common exercise. The water provides support and exercises important voluntary muscles in the process.

Surgery corrects what exercise and physical therapy cannot. When the shortening of muscles occur, surgery is used to correct the pull on an ankle or elbow.

Future Outlook/Research Of all the muscular dystrophies, Duchenne is the one that researchers concentrate on the most. Because of its fatal nature, scientists need to know more about it. They have already pinpointed the gene responsible for the disease, now they just need to know what they can do to fix this defect.

Some researches are attempting to decipher the chemical role of dystrophin, while others concentrate on the growth of new muscles or injections of copies of the defective gene into the muscles, which are called myoblasts. The myoblasts fuse with a damaged cell creating a healthy, new cell.

Like many other inherited diseases, some scientists believe that the cure lies within the insertion of a healthy gene, or gene therapy. Nevertheless, like many of the other methods, gene therapy is not a practical method for curing Duchenne Muscular Dystrophy.

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