Muscular dystrophy
Muscular dystrophy
Most types are caused by faulty DNA
There are many different types of muscular dystrophy (MD) - a group of conditions that progressively affect the muscles.
Most are inherited and they vary in severity depending on type.
There are no cures and no treatments to correct the loss of muscle cells that occur in MD.
But a great deal can be done to help limit the effects.
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What causes MD?
Most are caused by mutations in genes involved in muscle structure and function.
In some types of MD both the father and mother must have a faulty gene to pass it on, which is called recessive inheritance.
In other types, it only needs one parent to pass on a faulty gene, which is called dominant inheritance.
In one type, called Duchenne muscular dystrophy, the mother usually passes the faulty gene on to her son through the female sex chromosome, the X-chromosome.
Sometimes the abnormal genes appear for the first time without having been passed down by either parent.
What goes wrong?
These gene problems lead to damaged muscle cells that do not work properly.
This may cause difficulty walking, clumsiness, frequent falls, difficulty standing and breathing problems.
However, the symptoms and their severity vary with the different types of MD.
What are some of the different types of MD?
Congenital MD - are a group of conditions in which symptoms are apparent at birth or within the first six months. The muscle weakness causes the baby to appear floppy.
Duchenne MD - caused by an error in a gene called dystrophin and usually affects only boys, although there are rare cases in girls. It affects the muscles of the pelvis and thighs first, causing difficulty in walking between the ages of one and three.
Becker MD - rarely affects people before the age of 10, and is considered a milder form than Duchenne MD. Again, it mainly affects boys.
Emery-Dreifuss - typically starts in childhood or adolescence. The heart can also be affected.
Facioscapulohumeral MD - affects facial (facio), shoulder (scapul) and upper arm (humeral) muscles, although the legs can sometimes be affected too.
Oculopharyngeal MD - affects the eye (ocular) and throat (pharyngeal) muscles, with the first signs, such as droopy eyelids and difficulty swallowing, developing when the person is aged 50-60.
Who is affected?
Overall, about 1 in 2,000 babies born in the UK will have a neuromuscular disorder.
Duchenne MD is the commonest and most severe form. Around 100 boys are born with the condition in the UK each year .
What treatments are available?
There are treatments that can help alleviate symptoms, such as muscle spasm, and enable people with MD to lead a good quality of life.
Exercise and physiotherapy helps to keep the muscles in good condition.
Physical aids, such as braces or wheelchairs, can help the individual to maintain mobility.
Couples who know that MD runs in their family can opt for genetic counselling.
It is possible to test embryos while still in the womb to see whether they have inherited the genes responsible.
Doctors can also test an embryo conceived using IVF to check that it does not carry any faulty gene before it is put into the mother’s womb.