ATI RN
Pediatric Genetic Disorders Questions
Question 1 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 2 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.
Question 3 of 5
To evaluate abdominal distention, a KUB reveals a 'double bubble' sign. The best explanation for the neonate's abdominal distention is
Correct Answer: D
Rationale: The ‘double bubble’ sign on KUB indicates duodenal atresia, common in Down syndrome, causing a gas bubble in the stomach and proximal duodenum. Hirschsprung, meconium ileus, and plugs cause distal obstructions. Pyloric atresia is rarer and doesn’t produce this sign.
Question 4 of 5
The most common occurring mutations in humans are:
Correct Answer: D
Rationale: Aneuploidy (e.g., trisomy 21) is the most common chromosomal mutation in humans, especially in live births or conceptions. Indels and CNVs are frequent but less so, and polyploidy is rare in humans.
Question 5 of 5
This is an electrophoresis (southern blots) for an individual with hereditary retinoblastoma; both normal and tumor cells were genotyped for three polymorphic markers flanking the RBI locus on chromosome 13 for this patient (N=normal cells, T=tumor cells). Based on the figure, which of the following is the most likely to explain the genetic mutation in this patient's cancer?
Correct Answer: A
Rationale: Hereditary retinoblastoma involves one germline RB1 mutation. Tumorigenesis requires a second hit (Knudson’s two-hit hypothesis). Southern blot showing loss of normal allele in tumor cells suggests a second somatic mutation, not chromosome loss.