Question
The chances of having an unaffected baby, when both the parents are suffering from the condition as shown in the picture below is ?
A. 0%.
B. 25%.
C. 50%.
D. 100%.
Show Answer
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Correct Answer » B
Explanation
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In the picture above, both the parents are suffering from achondroplasia.
In accordance with an autosomal dominant inheritance pattern the chances of having an unaffected baby are 25%.
Achondroplasia is an autosomal dominant condition.
- Let ‘a’ represent the normal allele and A represent the achondroplasic allele.
Given that both parents have achondroplasia, the most favourable inheritance would be :
- 3 out of 4 children would be affected or 75% of children will be affected
- 1 out of 4 i.e. 25% children will be unaffected.
Note: We have chosen only a heterozygous state in both parents as the question is asking about the most favourable outcome possible. If both parents are homozygous 0% children will be unaffected.
