2014 Chromosome Microarray

Term

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Which of the following is a limitation of chromosome microarray?

A. Can not detect an unbalanced chromosomal translocation
B. Can not detect aneuploidy
C. Can not detect copy number variants (CNV's)
D. Can not detect low level mosaicism

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Terms in this set (13)

D: Correct

If low-level mosaicism is suspected, a high resolution karyotype (counting extra cells formosaicism) is the more appropriate test.

What is the approximate detection rate with chromosome microarray for global developmental delay, intellectual disability, and/or multiple congenital anomalies?

A. 15-20%
B. 30-35%
C. 5-10%
D. 1-3%

Answer: A

According to the American College of Medical Genetics and Genomics (ACMG), which is not an indication to utilize chromosome microarray as a first-tier test?

A. Multiple congenital anomalies
B. Non-syndromic developmental delay
C. Speech delay
D. Autism spectrum disorder

C: Correct

Further determination of the use of CMA testing for the evaluation of the child with growth retardation, speech delay, and other less well-studied indications is recommended, particularly by prospective studies and aftermarket analysis.

Which of the following chromosome aberrations would be detectable by chromosome microarray?

A. 46,XX,inv(4)(p14q21.3)
B. 46,XX,t(8;13)(q24.1;q14.1)
C. 46,XX,t(3;5)(p21;q31)
D. 46,XY,del(5)(q33q34)

Answer: D

Which of the following chromosome aberrations would be detectable by chromosome microarray?

A. Balanced translocation
B. Pericentric inversion
C. Isodicentric chromosome
D. Paracentric inversion

Answer: C

Which of the following statements regarding Copy Number Variants (CNV) is false?

A. Most micro-deletion and micro-duplication syndromes are caused by CNV's that are >500kb.
B. Approximately 45-50% of CNV's that are <500kb are benign.
C. Parental testing can help to determine the pathogenicity of CNV's of unclear clinical significance.
D. CNV's are a common type of genetic variation in the general population

Answer: B

This is FALSE. About 90-90% of CNV's that are <500kb are benign.

Runs of Homozygosity (ROH) can be detected by:

A. Oligonucleotide Array
B. SNP Array
C. Whole Exome Sequencing
D. BAC Array

Answer: B

Runs of Homozygosity can be detected by a Genome wide SNP Array or a combination Oligo-SNP array.

A long Run of Homozygosity (ROH) that is detected on a single chromosome is most likely due to:

A. Uniparental Disomy (UPD)
B. Recombination
C. Second-degree parental relationship
D. Copy Number Variation (CNV)

Answer: A

When ROH is observed on a single chromosome only, it can be indicative of UPD.
If it is distributed throughout the genome, it is more likely to be indicative of consanguinity.

The sum of the size of the runs of homozygosity divided by the total autosomal genomic length approximately equals:

A. % likelihood of a consanguineous union
B. % of UPD
C. % likelihood of an autosomal recessive condition
D. % Identical by Descent (IBD)

Answer: D

In long ROH, % IBD can be estimated by the sum of the sizes of the homozygous segments divided by the total autosomal genomic length
~2,881 Mb for GRCh37/hg19

Genomic regions that are identical by descent...

A. result in pre-mature protein truncation.
B. are caused by micro-duplications.
C. originate from the same ancestor.
D. always indicate an autosomal recessive condition.

Answer: C

Genomic regions IBD = originate from a common ancestor