Author Question: With an autosomal recessive disorder, it is important that parents understand that if they both ... (Read 78 times)

ETearle · **on:** Jun 25, 2018

With an autosomal recessive disorder, it is important that parents understand that if they both carry a mutation, the following are the risks to each of their offspring (each pregnancy):

A. 50 chance that offspring will carry the disease
B. 10 chance of offspring affected by disease
C. 25 chance children will carry the disease
D. 10 chance children will be disease free

Question 2

In autosomal recessive disorders, carriers have:

A. Two mutated genes; one from each parent that cause disease
B. A mutation on a sex chromosome that causes a disease
C. A single gene mutation that causes the disease
D. One copy of a gene mutation but not the disease

paavo · **Reply #1 on:** Jun 25, 2018

Answer to Question 1

ANS: A
It is important that parents understand that if they both carry a mutation, the risk to each of their offspring (each pregnancy) is an independent event: 25 disease free, 25 affected, and 50 carrier.

Answer to Question 2

ANS: D
Individuals who have an AR disorder have two mutated genes, one on each allele of the chromosome. Parents of an affected person are called carriers because each parent carries one copy of the mutation on one chromosome and a normal gene on the other chromosome. Carriers typically are not affected by the disease. In pedigrees with an AR inheritance patterns, males and females will be equally affected because the gene mutation is on an autosome.