Question

3. Cystic fibrosis is most common in individuals of Northern European descent, affecting 1 in 3200 newborns. Approximately 1 in 120 Asian Americans are carriers of cystic fibrosis. What is the approximate relative risk of this female having a child affected by cystic fibrosis with a Northern European partner, compared to an Asian American partner, assuming that both are of unknown genotype?

4.5-fold

2.2-fold

1.8-fold

0.2-fold

Answer 1

Probability of newborns of Northern European affected by cystic fibrosis ,P(E₁) = 1/3200

Probability that Asian Americansbare carriers of cystic fibrosis, P(E₂) = 1/120

Probability that female marries to Northern European, P(E₃) = 1/2

Probability that female marries to Asian American, P(E₄) = 1/2

Probability such that female having child affected by cystic fibrosis with a Northern European partner = P(E₃) * P(E₁) = (1/2) * (1/3200)

= 1/6400

Probability such that female having child affected by cystic fibrosis with a Asian Americans partner = P(E₃) * P(E₁) = (1/2) * (1/120)

= 1/240