Reading a DTC Report

There are a few key points to check when looking at any genetic test result.

• Check all patient identifying information carefully
• Family history is important contextual information
• Check the sample type and what sort of genetic testing has been done
• Be clear what the test result has shown, what it has excluded and what is has not excluded
• Do not over-interpret variants of uncertain significance and seek expert advice when necessary
• Signpost the patient back to the provider of their DTC test if there is detail that needs clarification.

A generalised genetic report might include:

• Health Predisposition information – carrying a variant confers a higher risk of disease eg age-related macular degeneration, BRCA1/2, Coeliac, Parkinsons
• Polygenic disease report – combining variants together to give an estimated risk of eg CHD, HT, DM, Migraine, restless legs
• Pharmacogenetic information – carrier of gene variant affecting drug metabolism eg CYP2C19
• Recessive gene carrier status – of interest for reproductive risk eg CF, polycystic kidney disease, Sickle cell disease, Gauchers
• Wellness report – estimates from polygenic factors eg genetic weight, lactose intolerance, alcohol flush reaction
• Ancestry – maternal and paternal haplotype reports indicating ancestral origins
• Polygenic Traits for fun eg musical pitch, cheek dimples, earwax type or fear of heights
• The report may include access to the entire genetic sequence of the patient’s genome

In most cases the variant that is checked for in the genetic test is the most common one(s) – less common variants are not excluded so for example, a negative DTC BRCA test may not definitely say that there are no rare pathogenic changes in the patient’s BRCA gene.

In Primary Care, we can take and assess family history, and give lifestyle advice. Beyond that, we may offer referral if indicated, or signpost back to the DTC provider.