Question

1) What are the two main types of muscular dystrophy (clinical names) linked to mutations in the dystrophin gene and how do they differ?

2)Describe (name it and explain how a diseased person is different from non-diseased) the phenotypic test used to indicate Duchenne muscular dystrophy.

3)How does the histology of muscle differ between a patient with Duchenne muscular dystrophy and that of a normal person?

Answer 1

1). Muscular dystrophy cause loss of muscles and prgressive weakness. Dystrophin protein coded by dystrophin (DMD) genes are found in cytoplasm, it connect the cytoskeleton to extracellular matrix. DMD gene is the longest known gene, it is of 2.b megabases approximately. Mutation in DMD gene cuases mainly two types of muscular dystrophy:

(a) Duchenne muscular dystrophy- symptoms of Duchenne muscular dystrophy are frequent falls, difficulty in rising from a lying or sitting position, trouble in running and jumping, waddling gait, walking on the toes, large calf muscles, muscle pain and stiffness, learning disabilities, growth is .delayed. symtoms appear in early childhood.

(b) Becker's muscular dystrophy- signs and symptoms of Becker's muscular dystrophy are similar to Duchenne muscular dystrophy, but milder and progress slowly. Symptoms generally begin in the teens but might not occur until the mid-20s or later. Symptoms occcur after 20 years of age or later.

2). Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet): in this progamme MD STARnet collects information about muscular dystrophy. On the basis of certain question regarding disease in patient MD STARnet collects information and use it for research and disease management.

3).

Musclesof patient with DMD	Normal person
Fiber size vary, Small fibers are round in shape, muscle fibres are often large, early necrosis, coarse muscle fibres.	Fiber Size vary, small fibers are round or polygonal, necrosis rarely occur.