ATI RN
Pediatric Genetic Questions
Question 1 of 5
Which of the following cannot used in karyotype?
Correct Answer: D
Rationale: Erythrocytes (D) cannot be used for karyotyping as they lack nuclei. Rationale: Karyotyping requires dividing cells with chromosomes; chorionic villi, lymphocytes, and bone marrow provide mitotic cells, but mature erythrocytes are enucleated.
Question 2 of 5
CML is caused by:
Correct Answer: C
Rationale: Reciprocal t(9;22) (C) causes CML (Philadelphia chromosome). Rationale: BCR-ABL1 fusion drives myeloid proliferation; Robertsonian involves acrocentrics (e.g., 14;21), not 9;22.
Question 3 of 5
Baby with macrocephaly and severe intrauterine growth retardation:
Correct Answer: B
Rationale: Digynic (B, maternal triploidy) fits. Rationale: 2 maternal + 1 paternal sets (69, XXX/XXY) cause small fetus, macrocephaly; diandric has large placenta.
Question 4 of 5
Pathogenic mutations in TBX5 cause Holt-Oram syndrome which includes cardiovascular (atrial septal defect, hypoplastic left heart syndrome), chest (Absent pectoralis major muscle) and skeletal anomalies (vertebral anomalies, triphalangeal thumb and carpal bone anomalies). The TBX5 phenotypic effect is related to which concept:
Correct Answer: C
Rationale: Pleiotropy (C) describes one gene affecting multiple traits. TBX5 mutations cause diverse effects (heart, chest, skeleton), fitting this concept. Rationale: Unlike reduced penetrance (variable expression), sex-limited (gender-specific), or multifactorial (many factors), pleiotropy explains TBX5’s broad impact.
Question 5 of 5
You are asked to consult about a 2-month-old girl with hypotonia, seizures, and an elevated plasma lactate (8 mM/L, normal deficiency. Which of the following is the most likely mode of inheritance in this infant?
Correct Answer: C
Rationale: Same as Q10; autosomal recessive (C) for PDH deficiency. Rationale: Recessive inheritance fits sporadic female cases; mitochondrial (maternal) or X-linked (male bias) are less likely without family history or sex skew.