ABMGG Cytogenetics and Chromosomal Analysis

Question 1

Which banding technique is most commonly used to produce a standard karyotype in clinical cytogenetics laboratories?

Accepted Answer

G-banding

Answer

Q-banding

Answer

R-banding

Answer

C-banding

Question 2

According to the ISCN (International System for Human Cytogenomic Nomenclature), how is a male with trisomy 21 correctly written?

Accepted Answer

47,XY,+21

Answer

46,XY,+21

Answer

47,XX,+21

Answer

46,XY,21q+

Question 3

Fluorescence in situ hybridization (FISH) is best suited for detecting which type of chromosomal abnormality?

Accepted Answer

Submicroscopic deletions at targeted loci

Answer

Whole genome aneuploidy

Answer

Balanced reciprocal translocations with no copy number change

Answer

Polyploidy

Question 4

A chromosomal microarray (CMA) using SNP probes has an advantage over array CGH in that it can detect:

Accepted Answer

Uniparental disomy (UPD)

Answer

Larger deletions

Answer

Balanced translocations

Answer

Telomeric fusions

Question 5

The most common cause of trisomy 21 (Down syndrome) is:

Accepted Answer

Meiotic nondisjunction

Answer

Robertsonian translocation

Answer

Mosaicism

Answer

Uniparental disomy

Question 6

Turner syndrome (45,X) most commonly results from loss of the sex chromosome derived from which parent?

Accepted Answer

Maternal X is retained; paternal sex chromosome is lost

Answer

Paternal X is retained; maternal sex chromosome is lost

Answer

Equal frequency from either parent

Answer

Always due to maternal nondisjunction

Question 7

Fragile X syndrome is caused by a CGG trinucleotide repeat expansion in the promoter region of which gene?

Accepted Answer

FMR1

Answer

DMPK

Answer

HTT

Answer

ATM