Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (known also as DMD) is a form of muscular dystrophy, which worsens more quickly than other forms (most notably Becker's muscular dystrophy).  This causes earlier death and the symptoms become increasingly worse very quickly.  Being classified with having DMD is a living nightmare.

DMD has one overwhelming cause, being a defective gene for dystrophin (a protein in the muscles).  DMD occurs in about 1 out of every 3,600 male infants.  However, it often occurs in people without a known family history of the condition.  Because of the way the disease is inherited, it predominately affects boys.  The sons of females who are carriers of the disease (women with a defective gene, but no symptoms themselves) each have a 50% chance of having the disease.  The daughters each have a 50% chance of being carriers.  Very rarely can the disease can affect a girl. Because this is an inherited disorder, risks include a family history of DMD. 

The name Duchenne comes from the doctor (Duchenne de Boulogne) who first studied this condition.

 The symptoms usually appear before age 6 and may appear as early as infancy. Typically, the first noticeable symptom is delay of motor milestones, including sitting and standing independently. The mean age for walking in boys with DMD is 18 months. There is progressive muscle weakness of the legs and pelvic muscles, which is associated with a loss of muscle mass (wasting). This muscle weakness causes a waddling gait and difficulty climbing stairs. Muscle weakness also occurs in the arms, neck, and other areas, but not as severely or as early as in the lower half of the body. Calf muscles initially enlarge and the enlarged muscle tissue is eventually replaced with fat and connective tissue (pseudohypertrophy). Muscle contractures occur in the legs, making the muscles unusable because the muscle fibers shorten and fibrosis occurs in connective tissue. Occasionally, there can be pain in the calves. Symptoms usually appear in boys aged 1 to 6. There is a steady decline in muscle strength between the ages of 6 and 11 years. By age 10, braces may be required for walking, and by age 12, most boys are confined to a wheelchair. Bones develop abnormally, causing skeletal deformities of the spine and other areas. Muscular weakness and skeletal deformities frequently contribute to breathing disorders. Cardiomyopathy (enlarged heart) occurs in almost all cases, beginning in the early teens in some, and in all after the age of 18 years. Intellectual impairment may occur, but it is not inevitable and does not worsen as the disorder progresses. Breathing complications and cardiomyopathy are common causes of death. Few individuals with DMD live beyond their 30s.

There is no cure for DMD at present. However, treatments (that vary among age group) can help.

Pre-school age

Usually, at this stage, your child will be well and not need much treatment. What you will usually be offered is:

• Information about DMD. You may wish to be in touch with patient support groups or other families with DMD.
• Referral to a specialist team so that your child's health can be monitored. The specialist team may include a doctor who specialises in the medical care of children (a paediatrician), or a specialist in muscle and nerve conditions (a neurologist), and a physiotherapist and specialist nurse.
• Advice about the right level of exercise for your child.
• Genetic advice for the family. You may wish to have tests to see whether anyone else in the family has the DMD gene. This may be important to families who are thinking of having more children.

Age 5-8 years

At this age, some support may be needed for the legs and ankles. For example, using nighttime ankle splints, or with a longer brace called a knee-ankle-foot orthosis (KAFO).

Treatment with medication called corticosteroids (or steroids) can help to maintain the child's muscle strength. This involves taking medication such as prednisolone or deflazacort as a long-term treatment, either continuously or in repeated courses. Steroid medication can have side effects, so the pros and cons of this treatment need to be weighed up, and the treatment needs to be monitored for side-effects.

8 years to late teenage years

At some time after the age of 8 years, the child's leg muscles become significantly weaker. Walking gradually gets more difficult, and a wheelchair is needed. The age at which this happens varies from person to person. Often it is around age 9-11 years, although with corticosteroid treatment, some boys can walk for longer.

After the child starts needing a wheelchair, this is also the time that complications tend to begin, so it is important to monitor the boy's health and to treat any complications early.  Your child will need regular check-ups. This may involve different specialists - for example, heart and lung checks, orthopedic care for bones and joints, physiotherapists, and dieticians.

Practical support and equipment will be needed at this stage - for example, wheelchairs and adaptations to the child's home and school. Occupational therapists can advise about this. Various services can assist with equipment, care, holidays and breaks. There is usually provision from local health and social services. Also, various charities which can assist with equipment, holidays and other forms of care.

Counseling and emotional support for you and/or your child may be helpful.

Late teenage years to 20s

At this stage, muscle weakness becomes more problematic. Increasing help and adaptations are needed. Complications such as chest infections are likely to increase, so more medical monitoring and treatment are required.

There is a lot of research taking place aiming to improve treatment and perhaps find a cure for DMD. Some aspects of current research are:

• Establishing the best type and dose of steroid treatment to help maintain muscle strength.
• Whether gene therapy can be used to cure DMD or prevent loss of muscle. There is a recent trial involving a type of gene therapy called 'exon skipping'. The first results are promising, although this research is still in a very early stage.
• 'Cell therapy' which may be possible, using cells that produce normal dystrophin.
• A form of drug (pharmacological) treatment that may be feasible, helping to produce a protein called 'utrophin' which is similar to the missing dystrophin.

Works Cited

Database, Malacards Human Disease. "Duchenne Muscular Dystrophy (DMD)." malacard.org. Weizmann Institute of Science, 3 Feb. 2015. Web. 16 Apr. 2015. <http://www.malacards.org/card/duchenne_muscular_dystrophy>.

Kenny, Tim. "Duchenne Muscular Dystrophy." Patient. N.p., 13 May 2013. Web. 17 Apr. 2015. <http://www.patient.co.uk/health/duchenne-muscular-dystrophy-leaflet>.

Medline Plus. "Duchenne Muscular Dystrophy: MedlinePlus Medical Encyclopedia." U.S National Library of Medicine. U.S. National Library of Medicine, 9 Apr. 2015. Web. 15 Apr. 2015.

National Human Genome Research Institute. "Learning about Duchenne Muscular Dystrophy." National Human Genome Research Institute. National Human Genome Research Institute, 18 Apr. 2013. Web. 16 Apr. 2015. <https://www.genome.gov/19518854#2>.