ATI RN
Pediatric Genetic Disorders Questions
Question 1 of 5
The MOST common genetic defect of Prader-Willi syndrome (PWS) is
Correct Answer: B
Rationale: PWS is most commonly due to paternal 15q11-13 deletion (B, ~70%). Rationale: Maternal deletion (A) causes Angelman; paternal UPD (C) is less common (~25%).
Question 2 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 3 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 4 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.
Question 5 of 5
Multifactorial inheritance is characterized by all of the following EXCEPT
Correct Answer: C
Rationale: Multifactorial inheritance involves multiple genes and environment, with sex predilection (e.g., pyloric stenosis), recurrence rates of 2-10%, and twin concordance of 20-63%. Severe symptoms can increase risk. Symptomatic carriers apply to monogenic traits, not multifactorial.