Question

Investigate a disorder or disability that is genetically inherited, and write a two- to three-page paper on the genes involved, the inheritance pattern, and any genetic complexities discovered. By genetic complexities I mean, for example, is only one gene involved, or multiple genes? Are there environmental factors that play a role? Are there variations in the disorder? Are there related disorders found among carriers?

I suggest a good source for valid information would be an association set up for family members of those who have a disorder. You can also have a look at the Genetics Home Reference from the National Institutes of Health.

Answer 1

MYOTONIC DYSTROPHY (DM)

" Myotonic dystrophy is a genetically inherited condition characterized by muscle weakness and wasting."

Myotonia refers to the condition having inability of a person to relax muscle which leads to progressive muscle degeneration and weaknesses. DM also affects many other organs. It's affect in skeletal muscle causes hampered limb and trunk movement, in smooth muscle hamperes peristalsis and in cardiac muscle it affects the heart.

Causes:

There are two types of DM

1. DM1, this takes place when gene present on chromosome no. 9 known as DMPK has as abnorma expanded section
2. DM2, this takes place when gene present on chromosome no. 3 called ZNF9 have abnormally expansex section.

These abnormally expanded sections mainly affects the cellular processes.

Symptoms:

The symptoms of DM1 are more severe than DM2. The DM1 mainly involves the muscle dystrophy of legs, hands neck and face while DM2 involves the muscle dystrophy of neck, shoulder, elbow and hips.

The other symptoms may include cataract, cardiac conduction and diabetes defect.

DM1 can be congenital also it includes the muscle weakness, breathing problems and intellectual disability.

As the disease progresses the heart can develop abnormal rhythm and the heart muscle can be weaken causes inadequate breathing especially at night time.

Diagnosis:

The diagnosis of myotonic dystrophy depends on the clinical history including family history, physical examination and proper laboratory test. The laboratory diagnosis may also include electromyography (EMG) testing and muscle biopsy. Muscle biopsy is very helpful in determining the weakness if caused by muscle dystrophy, an inherited disorder or by others acquired cause of muscle degeneration.

Treatment or management:

The treatment of myotonic dystrophy is done by multidisciplinary team which include a drug named mexiletin prescribed by the well qualified neurologist to relax the weak muscle. An ECG is also done to see the heart rhythm as well as heart function.

Specialized rehabilitation is also required to meet with patients exercise and strengthening program and stretching for tighten muscle and contractures. Also the splints and orthotics are checked if required to fullfil the hand and foot dysfunction.

It is a full or partially curable disesa. Just need a proper health care and functional re-education.