ABMGG Cytogenetics and Chromosomal Analysis 2

Question 1

The Philadelphia chromosome, found in chronic myelogenous leukemia (CML), results from which chromosomal rearrangement?

Accepted Answer

Reciprocal translocation t(9;22)(q34;q11.2)

Answer

Inversion of chromosome 9

Answer

Deletion of chromosome 22q

Answer

Trisomy 9

Question 2

A pericentric inversion involves a chromosomal segment that:

Accepted Answer

Spans the centromere, including both arms

Answer

Does not include the centromere

Answer

Involves only the short arm

Answer

Results in a ring chromosome

Question 3

A carrier of a balanced reciprocal translocation is at risk of producing offspring with which abnormality?

Accepted Answer

Offspring with unbalanced chromosomal segments causing partial monosomy or trisomy

Answer

Only normal offspring

Answer

Only monosomic offspring

Answer

Offspring with whole-chromosome aneuploidy

Question 4

Chromosomal mosaicism in a patient is BEST defined as:

Accepted Answer

The presence of two or more cytogenetically distinct cell lines from the same zygote

Answer

Two different chromosomal structural variants in the same cell

Answer

A heterozygous deletion detectable by FISH

Answer

Copy number variation between maternal and paternal alleles

Question 5

Uniparental disomy (UPD) can cause disease even when both copies of a chromosome are structurally normal primarily because of:

Accepted Answer

Genomic imprinting causing silencing of maternally or paternally imprinted genes

Answer

Dosage imbalance from two copies of one chromosome

Answer

Increased recombination frequency

Answer

Loss of heterozygosity for oncogenes

Question 6

Array comparative genomic hybridization (aCGH) detects copy number variants (CNVs) by comparing:

Accepted Answer

Hybridization intensity of patient DNA vs. a reference DNA on oligonucleotide probes

Answer

Patient DNA methylation to a reference panel

Answer

Patient RNA expression levels to normal tissue

Answer

Sequence reads from patient DNA to a reference genome

Question 7

Spectral karyotyping (SKY) and multicolor FISH (M-FISH) are especially useful for identifying:

Accepted Answer

Complex chromosomal rearrangements and marker chromosomes of unknown origin

Answer

Point mutations within a gene

Answer

Repeat expansion disorders

Answer

SNP-level variants