ATI RN
Pediatric Genetic Disorders Questions
Question 1 of 5
Of the following, the MOST common type of X-linked inheritance is
Correct Answer: B
Rationale: Color blindness (B) is the most common XLR disorder (1 in 12 males). Rationale: Hemophilia (D) and fragile X (E) are less frequent; Rett (A) is XLD.
Question 2 of 5
A 24-year-old pregnant lady in 2nd trimester comes to your clinic worried about her exposure to CXR done for suspicion of pneumonia last week; she is highly concerned about possibility of congenital anomalies. Of the following, the BEST advice to her is that
Correct Answer: D
Rationale: A single chest X-ray (low dose, <0.1 mGy) is negligible. Rationale: Fetal risk is significant only >50 mGy; 2nd trimester is less sensitive than 1st.
Question 3 of 5
Children with Down syndrome are most likely diagnosed clinically in the neonatal period. All the following are characteristic facial features EXCEPT
Correct Answer: B
Rationale: Down syndrome features include macroglossia (A), hypoplastic midface (C), flat nasal bridge (D), and down-slanting fissures (E); flattened occiput (B) is not typical. Rationale: Occiput is often normal or prominent.
Question 4 of 5
You are evaluating a neonate with multiple dysmorphic features, you find him small for gestational age, microcephalic, single nostril, postaxial polydactyly and rocker-bottom feet. Of the following the MOST likely diagnosis is
Correct Answer: A
Rationale: Patau syndrome (trisomy 13, A) matches microcephaly, polydactyly, and rocker-bottom feet. Rationale: Single nostril (holoprosencephaly) is classic Patau.
Question 5 of 5
Tay-Sachs disease is best described by
Correct Answer: B
Rationale: Tay-Sachs is an autosomal recessive disorder caused by a single genetic defect in the HEXA gene, leading to enzyme deficiency. While more common in Ashkenazi Jews, it’s not exclusive to them. It affects both sexes, lacks genetic heterogeneity in its classic form, and is infantile-onset, not adult.