Intro To Cytogenomics

Question 1

Chromosomal microarray, quantitative fluorescence PCR and genomic sequencing are all based on what

Answer 1

DNA

Question 2

What disease is an example of a numerical abnormality

Answer 2

DS, extra chr. 21

Question 3

What is an aneuploid numerical abnormality

Answer 3

Gain/loss of one or few chr.

Question 4

What are the two types of structural abnormalities

Answer 4

Robertsonian translocation (14;21) - involve Acrocentric chromos
Reciprocal translocation (11;22) - exchange of material between 2 non homo chromos

Question 5

Why do robertsonian translocations involve 45 not 46 chromosomes

Answer 5

The q arms fuse to create one larger chr with centromere in centre. P arms fuse to form mini DNA segment with few genes and no centromere which is usually lost by cell

Question 6

What is mosaicism

Answer 6

Cell lines with different chromosomal constitution in same individual

Question 7

What are some clinical impacts of cytogenic variants

Answer 7

Reproductive issues
Cancer
Ambiguous genitalia
Neurodevelopmental issues

Question 8

When are chromosomal abnormalities normally detected

Answer 8

Prenatally. Risk of chr abnormality increases with maternal age