Achondroplasia
Achondroplasia is an autosomal dominant disorder,however homozygous dominant individuals do not have achondroplasia - they either die before birth or very shortly thereafter.The homozygous recessive condition is normal.A dwarf couple decide to have children.Use this information to answer the following question(s).
-In the example above,what is the probability that this couple will have a normal child?
A) 0
B) 1/4
C) 1/3
D) 2/3
E) 1/2

Question

Quizplus · Accepted Answer

Since both parents have the autosomal dominant disorder achondroplasia, they are heterozygous (Aa) and there is a 25% chance they will pass on the recessive allele to their offspring, resulting in a normal child (aa). Therefore, the probability of having a normal child is 1/4 or 25%, which corresponds to choice C.

Achondroplasia Achondroplasia Is an Autosomal Dominant Disorder,however Homozygous Dominant Individuals Do