DTC testing + Cancer risk prediction

Question 1

What are the three pathways to genetic testing?

Answer 1

Direct-to-Consumer, Physician-Mediated, Physician-Directed

Question 2

Who might be using consumer-initiated genetic testing?

Answer 2

Patients without health insurance or with high deductibles, patients who want to test under a pseudonym for privacy, military (no medical record inclusion), elderly patients in nursing homes (medicare will not cover)

Question 3

Limitations to DTC testing for hereditary cancer risk (BRCA1/2, MUTYH)?

Answer 3

BRCA1/2 only tests for 3 variants most common for Ashkenazi Jewish individuals; MUTYH tests for 2 variants in Northern European individuals; high rate of false negatives by ethnicity

Question 4

Limitations to DTC testing

Answer 4

Not all-encompassing comprehensive genetic tests, may not be diagnostic and could need confirmation testing, possibly inadequate analytical or clinical validity, the chain of custody is not ensured, genetics is part of disease risk, results could be lacking clinical utility

Question 5

Risks to DTC testing

Answer 5

May not be an appropriate test for the individual, false pos/neg results, misinterpretation of results, distress/anxiety risk, or inappropriate actions taken based on results.

Question 6

Polygenic Risk Score Calculation

Answer 6

PRS = b (x-u) (add for multiple SNPs)
b= per-allele log OR
x= number of alleles in the patient (0, 1, 2)
u= average number of alleles in population (0, 1, 2)