ATI RN
Pediatric Genetic Disorders Questions
Question 1 of 5
The figure below represents the pedigree of a family with neurofibromatosis type 1 with the arrow indicating the proband. This pedigree shows a:
Correct Answer: A
Rationale: NF1 is autosomal dominant. Without the figure, typical AD inheritance is assumed (affected in each generation).
Question 2 of 5
One of the following is true about telomerase:
Correct Answer: D
Rationale: Telomeres consist of TTAGGG repeats throughout (D is true). Rationale: Telomerase uses an RNA template (not DNA, B false), extends the 3’ end (C misleading), and is active in cancer (A false). Activity decreases with age (E false). 'D' fits best.
Question 3 of 5
A female with a flattened face, small head, short neck, protruding tongue, small ears, and a poor muscle tone (hypotonia). She probably has a genetic disorder that's caused by?
Correct Answer: A
Rationale: Trisomy 21 (Down syndrome, A) matches these features. Rationale: Flat face, short neck, hypotonia, etc., are classic Down syndrome signs. Monosomy X (Turner) and Trisomy X have different phenotypes (e.g., short stature vs. subtle effects).
Question 4 of 5
Trisomy 47,XYY is a syndrome with signs and symptoms that range from being barely noticeable to learning disabilities, speech delay, low muscle tone. How would you expect this syndrome to have occurred?
Correct Answer: D
Rationale: Paternal nondisjunction causes 47, XYY. Rationale: Nondisjunction in paternal meiosis II results in YY sperm (24, YY), fertilizing an X egg (23, X), yielding 47, XYY. Dispermy or endomitosis would yield triploidy or tetraploidy.
Question 5 of 5
A person whose karyotype is 45, XX, t(15q;21q). If she mates with a 46, XY normal individual. What is the possibility that they will have a zygote which will develop into Down syndrome? ('t' is translocation):
Correct Answer: A
Rationale: 1/6 (A) is correct. Rationale: Robertsonian t(15;21) carrier (45, XX) produces 6 gamete types: normal 15+21, t(15;21), 15, 21, null 15, null 21. With normal sperm (15+21+Y), only 21+t(15;21) yields 47, +21 (Down). 1/6 gametes result in trisomy 21.