Question

1) Where are deletions most likely to occur in this dystrrophin gene?

2) Explain why elevated blood creatine kinase levels are a good proteomic marker for Duchenne muscular dystrophy.

3) Why is it more difficult to screen females for variants in the dystrophin gene?

4)In a muscle cell, where is the dystrophin protein located?

Answer 1

1) dystrophin Gene is made up of 79 exons. Sk it may have multiple deletion mutations which can cause the disease. But most commonly found deletion mutation is deletion of exon 44 or exon 45. These regions are more commonly found to be deleted in the diseased person.

2) duchenne muscular dystrophy is a serious muscle damage disease. Here muscle weakness begins at early age of life , which lead to muscle wasting and damage. Creatin kinase is an enzyme present in very large amount in muscle. In this disease due to damage of muscle , this enzyme is released in very large amount in blood because very large amount of this enzyme present in muscle only.

Presence of CK in blood indicate muscle disease.

3) duchenne muscular dystrophy is a X linked disorder. It is more common manifested in males ( as they has only one X chromosome). Females mainly act as carrier because females has 2 X chromosome. Instead of having one defective X chromosome, females will not menifest the disease due to other normal X chromosome. That is why it is difficult to screen females for duchenne muscular dystrophy.

4) Dystrophin protein located between the outermost layer of myofilaments and sarcolema in the muscle fiber (myofiber). It links actin filaments to various support proteins which are present inner surface of plasma membrane of each muscle fibers.