Muscular dystrophy Information
These progressive genetically determined disorders of skeletal and sometimes cardiac muscle have a complex clinical and neurogenetic classification.
Clinical features of
The boy with DMD is noticed to have difficulty in running and in rising to an erect position from the floor, when he has to use the hands to climb up his legs (Gowers' sign). There is initially a proximal limb weakness with pseudohypertrophy of the calves. The myocardium is affected. The boy becomes severely disabled by the age of 10.
Muscular dystrophy symptom
- Duchennes Muscular dystrophy (DMD)
- Becker's muscular dystrophy
- Limb girdle muscular dystrophy (LGMD)
- Facioscapulohumeral muscular dystrophy
- Myotonic muscular dystrophy
- Congenital muscular dystrophy
Diagnosis is often made on clinical grounds alone. Creatine phosphokinase is grossly elevated (100-200 times normal). Muscle biopsy shows characteristic variation in fibre size, fibre necrosis, regeneration and replacement by fat, and on immunochemical staining an absence of dystrophin. EMG shows a myopathic pattern.
Treatment and management of
There is no curative treatment. Passive physiotherapy helps to prevent contractures in the later stages of the disease. Portable respiratory support gives a substantially improved life expectancy.
Carrier detection. A female with an affected brother has a 50% chance of carrying the gene. In carrier females, 70% have a raised creatine phosphokinase level and the remainder usually have electromyographic abnormalities or changes on biopsy. Accurate carrier and prenatal diagnosis can be made using cDNA probes that are co-inherited with the DMD locus.
Genetic advice and counselling about possible termination of pregnancy should be given. Determination of fetal sex by amniocentesis and selective abortion of a male fetus is sometimes carried out. Many proven carrier females choose not to have offspring.