ATI RN
Genetic Disorders in Pediatrics Questions
Question 1 of 5
All the following are characteristic features of Williams syndrome EXCEPT
Correct Answer: D
Rationale: Williams syndrome (7q11.23 deletion) includes hypercalcemia (A), elfin face (B), blue irides (C), and friendly personality (E); IQ is typically low (D is false). Rationale: Mild intellectual disability is common.
Question 2 of 5
Hypomelanosis of Ito is characterized by all of the following EXCEPT
Correct Answer: D
Rationale: Hypomelanosis of Ito features hypopigmented skin patterns, ocular/CNS issues, and mosaic chromosomal anomalies (autosomal or sex chromosomes). Skin fibroblast studies often show mosaicism, not normal chromosomes.
Question 3 of 5
A mutation leading to:
Correct Answer: B
Rationale: Advanced paternal age increases de novo mutations (e.g., in sperm), linked to conditions like hearing loss or autism. Trisomies (e.g., Edwards) and recessive disorders (e.g., CF, Tay-Sachs) are more tied to maternal age or inheritance, not paternal age.
Question 4 of 5
A unaffected couple who are first cousins request counseling regarding their risk of having a child with alpha-1-antitrypsin deficiency, a rare autosomal recessive trait. Their parents are unaffected. Their shared grandfather is affected with the disorder and their shared grandmother is heterozygous. What is the risk to their child of being HOMOZYGOUS FOR A VARIANT FOR THE CONDITION? (disregard the population carrier frequency)
Correct Answer: A
Rationale: Each parent has a 1/2 chance of inheriting the heterozygous allele from their grandmother (carrier). Probability both are carriers = 1/2 × 1/2 = 1/4. If both are carriers, the child has a 1/4 chance of being homozygous. Total risk = 1/4 × 1/4 = 1/16.
Question 5 of 5
Most cancers cases occur due to:
Correct Answer: B
Rationale: Most cancers arise from somatic mutations or epigenetic changes in adult cells, not germline variants (heritable cancers are rare) or meiotic errors (related to aneuploidy, not cancer).