Seven months pregnant, an expectant mother was undergoing a routine ultrasound.

Question

Seven months pregnant, an expectant mother was undergoing a routine ultrasound. While prior tests had been normal, this one showed that the limbs of the fetus were unusually short. The diagnosis was that the baby had a genetic form of dwarfism called achondroplasia but both parents had no family history for this condition. Achondroplasia dwarfism is an autosomal dominant mutation with a frequency of about 1 in 25,000 births. Answer the following questions:
3) What is the chance that her child would also have this disorder

Explanation / Answer

Her child has a 50% chance of having this disorder. As homozygous mutants are not viable, only heterozygotes can pass on the defective allele. As the mother is heterozygous, the child has 50% chance to get the normal allele and 50% chance to get the defective allele from her mother.

Related Questions

Navigate

• Browse (All)
• Browse S
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.