ATI RN
Genetic Pediatric Questions
Question 1 of 5
A European couple with diagnosis of hearing loss in father's brother in autosomal recessive variant. What is the probability to have an AFFECTED FETUS? Knowing that the carrier frequency of this variant in the European population is around 1/30.
Correct Answer: D
Rationale: Father’s brother affected means father has 2/3 chance of being a carrier (since parents are carriers). Mother’s carrier chance is 1/30 (population frequency). If both are carriers (2/3 × 1/30 = 2/90), child has 1/4 chance of being affected. Total = 2/90 × 1/4 = 1/180.
Question 2 of 5
A gain of abnormal function rather than excessive activity in an oncogene could most probably occur through:
Correct Answer: A
Rationale: A point mutation in an exon can alter protein function (e.g., RAS mutations), causing abnormal activity, unlike promoter mutations or amplification, which increase expression.
Question 3 of 5
Chromosomal analysis reveals a 47,XYY karyotype. Which of the following descriptions best fits this abnormality?
Correct Answer: C
Rationale: 47,XYY is an extra Y chromosome in a male (normal is 46,XY), classifying it as a sex chromosome aneuploidy.
Question 4 of 5
Several inherited disorders are much more common in close-knit religious communities, such as the Amish (Jews), than in the general population. This is at least partly due to the fact that:
Correct Answer: A
Rationale: Inbreeding (marrying relatives) increases the frequency of homozygous recessive disorders due to a higher chance of inheriting two copies of a rare allele.
Question 5 of 5
Human males are much more likely to be have hemophilia (a failure of blood to clot properly) than human females. This is the case because:
Correct Answer: D
Rationale: Hemophilia is X-linked recessive. Males (XY) express it with one mutant allele, while females (XX) need two, making it rarer in females.