Thomas\'s brother, at the age of 47, was diagnosed with Huntington\'s Disease (H

Question

Thomas's brother, at the age of 47, was diagnosed with Huntington's Disease (HD). This is a dominantly inherited disease, with symptoms manifesting around the age of 45 and leading to death around age 60-70. Thomas, age 37, now wonders what his chances of having the gene for the disease are, and wonders if he should be tested. Thomas has another brother, age 52, who has not yet shown any symptoms of the disease. Thomas has three teenage children, a boy and two girls. There is no history of the disease in Thomas's wife's family. 1. Considering what you know of genetics, if you were a genetic counselor, how might you counsel Thomas as he considers whether or not to be tested? 2. If Thomas tests positive for HD, and you were one of his children, would you want to be tested? Why or why not? 3. If Thomas tests negative for HD, is there any chance his children would be afflicted with the disease? Why or why not?

Explanation / Answer

1. Considering what you know of genetics, if you were a genetic counselor, how might you counsel Thomas as he considers whether or not to be tested?

In autosomal dominant inheritance, only one copy of a disease allele is necessary for an individual to be susceptible to expressing the phenotype.

In Huntington's Disease With each pregnancy, there is a one in two (50%) chance the offspring will inherit the disease allele. Therefore Thomas has 50% chance of developing the disease. Therefore I would suggest him to get himself tested for HD

2. If Thomas tests positive for HD, and you were one of his children, would you want to be tested? Why or why not?

Yes I would want myself tested for HD. In Huntington's Disease With each pregnancy, there is a one in two (50%) chance the offspring will inherit the disease allele. Therefore if thomas is tested positive, there is a chance that 50% of his offsprings would suffer from HD.

3. If Thomas tests negative for HD, is there any chance his children would be afflicted with the disease? Why or why not?

HD is an autosomal dominant disease, hence a single disease allele is a must for disease. If Thomas tests negative for HD that means he cannot transfer disease allele to his children nor his wife, therefore the chance his children would be afflicted with the disease is nil.

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.