Bonus problem. (25 points). Man (III-1) suffering from a very rare genetic disea
ID: 252637 • Letter: B
Question
Bonus problem. (25 points). Man (III-1) suffering from a very rare genetic disease contacted the genetic counselor to find family. Pedigree is shown in the picture below. The genetic counselor then tells the man that daughters will have the genetic disease. Answer the following questions: out can he pass this disorder to his children. Counselor put together pedigree of the man he cannot pass the trait onto his sons, but that, even if he marries a normal woman, all his 1. What mode of inheritance did the genetic counselor imply with his advice to the man? 2. Do you agree with the conclusions of the counselor and the advice that he gave? Choose (10 points). Explain your conclusion. from below listed possibilities. Explain why you chosen one of them. (15 points). a. No. Recessive X-linked inheritance is still a likely possibility, and the man should have been informed of that No. Autosomal dominant inheritance is clearly indicated. In that case, if the man marries a phenotypically normal woman, there is a 50:50 chance that any child b. would be affected. Yes and no. The counselor has good reason to suspect X-linked dominant c. inheritance, but he should have alfo considered another mode of inheritance as a possibility (which one?). Yes and no. The counselor was correct in his conclusion about the mode of inheritance, but incorrect in his predictions about the possible progeny of the man. d. Proband Answer to 1: 10 of 11 2 of 1286E
Explanation / Answer
Ans1. According to the given pedigree, the mode of inheritance of disease is dominant X-linked inheritance, where X chromosomes carry dominant genes for disease. In this type of inheritance, all affected fathers have affected daughters, but affected fathers cannot transmit the disease to their sons. However, affected mothers can transmit the disease to both her sons or douhters, depending upon the whether a recessive or chromosome is passed on.
Ans.2). The given pedigree is showing all characteristics of X-linked dominant inheritance, it may possible that the mode of inheritance of this disease is autosomal dominant inheritance. Because, in autosomal dominant inheritance, matting between a normal person and an affected person results in 50% affceted offsprings and trait does not skip generations. Option (c) is given as 'the counselor has good reason to suspect X-linked dominant inheritance, but he should have also considered another mode of inheritance as a possibility'. Hence, it is a correct answer.