Muscular dystrophy and genetic testing

Muscular dystrophy is a neuromuscular disease which causes progressive weakness and loss of muscle mass. It occurs due to abnormal genes interfering with the production of proteins needed to form healthy muscle. Most of the symptoms of muscular dystrophy begin in childhood, whereas, the chronic symptoms don’t surface until adulthood. Progressive muscle weakness is the main sign of muscular dystrophy.

There are several diagnostic procedures that help in confirming if a person is suffering from a neuromuscular disease. One of them is genetic testing. The diagnostic procedure uses blood samples and examines them at the genetic level for a mutation that might be causing the neuromuscular disease. Read on as the article discusses more about the diagnostic procedure and its efficiency in confirming if the person is suffering from muscular dystrophy.

Genetic testing
As discussed above, genetic testing is used to analyze the cells in a blood, tissue, or saliva sample to look for specific mutations in the DNA that might be causing muscular dystrophy or other neuromuscular diseases. It is believed that each of the 30 different types of muscular dystrophy is associated with a unique genetic mutation. These mutations repeat their genetic codes in a single piece of ribonucleic acid (RNA).

There are commercial genetic tests such as direct genetic testing used to diagnose Duchenne muscular dystrophy (DMD), Becker muscular dystrophy (BMD), facioscapulohumeral muscular dystrophy (FSHD) and myotonic muscular dystrophy (DM). It can take weeks or months to receive the results of genetic testing as multiple genetic tests might be needed to find the genetic defect that could be causing the muscular dystrophy.

The significance of genetic testing
Clinicians and doctors recommend genetic testing, which might include family studies and direct genetic tests to identify the symptoms of muscular dystrophy or another neuromuscular condition. Direct genetic testing refers to the method of looking for a specific mutation in the genes. A blood sample is typically used for this type of diagnostic procedure.

If gene alteration is not observed in direct genetic testing, then markers such as chunks of DNA located near an irregular genetic sequence can be used to deduce similarities among family members. This is called as a family genetic testing. The accuracy of family testing depends on the proximity of the markers to the irregular gene sequence. Family genetic testing requires an adequate amount of blood samples from as many family members as possible.

Another form of genetic testing called parental genetic testing is carried out during pregnancy. It determines if the unborn child has inherited the mutated gene that might cause muscular dystrophy. Parental genetic testing is performed using two methods, amniocentesis and chorionic villus sampling (CVS). The procedure of these two testing differs on the basis of sample collection. While CVS is typically from the placenta of an 11-week pregnant mother, amniocentesis is usually performed on a 15 weeks pregnant mother using a sample from the amniotic fluid of the womb.

Carrier detection tests are done on a person who shows no symptoms of muscular dystrophy but has a genetic mutation or an irregular gene sequence associated with the disease. If a person is a carrier of a particular form of dystrophy, they stand a risk of passing muscular dystrophy to the future generation.