Is it possible for two parents with achondroplasia to have a child who is of normal stature?
A)Yes, because the disorder is autosomal dominant, and if both parents are heterozygous, the child could inherit two normal stature gene alleles.
B)Yes, if the parent who is homozygous for the gene mutation demonstrates variable expressivity of the health problem.
C)No, because the disorder is autosomal recessive, and the child can only inherit two mutated gene alleles for the health problem.
D)No, because homozygosity for this health problem is lethal.

Question

Quizplus · Accepted Answer

Achondroplasia is an autosomal-dominant trait that is lethal when the genotype is homozygous. Thus, both parents must be heterozygous A/n (with an A allele for achondroplasia and an n allele for normal stature). Normal stature (n allele) is recessive. Thus, for a child to have a normal-stature phenotype from these two parents, her or her genotype would have to be n/n. As shown by the Punnett square, the chances for this couple to have a child with normal stature is 25% with each pregnancy.

Is It Possible for Two Parents with Achondroplasia to Have