DNA diagnostics

Question 1

Standard DNA tests

Answer 1

Mutations in single genes

Question 2

Genome-scale DNA sequencing

Answer 2

Single-gene mutations in many genes and large-scale rearrangements; e.g., deletion or duplication of multiple genes

Question 3

Cytogenetic tests

Answer 3

Large-scale rearrangements

Question 4

Biochemical tests

Answer 4

An “indirect” genetic test that looks at abnormal analytes that may accumulate in the presence of a genetic disease

Question 5

In what scenarios is Genetic Testing is Used?

Answer 5

Diagnosis
Is this patient’s liver failure caused by a treatable genetic disease?
Presymptomatic diagnosis
Does this woman with a family history of breast cancer have a genetic predisposition?
Prenatal diagnosis
Is this Ashkenazi Jewish woman carrying a fetus with Tay Sachs disease?
Prevention
Will my patient develop deafness if treated with an aminoglycoside antibiotic?
Screening
All newborns in the U.S. are screened for a series of treatable diseases that have an onset in the newborn

Question 6

What do errors in DNA replicaiton, repair, epigenetic modification result in?

Answer 6

Structural Rearrangements: deletion, duplication, inversion translocation, amplification, uniparental disomy
Numerical Abnormalities
Aneuploidy
polyploidy

Question 7

Aneuploidy

Answer 7

Gain or loss of one or a few chromosome (24 ch)

Question 8

polyploidy:

Answer 8

Gain or loss of a whole ploidy (3n, 4n, …)

Question 9

When do most numerical Rearrangements happen?

Answer 9

in prenatal setting

Question 10

How

Answer 10

interchromosomal

intrachromosomal