Types of DTC testing available online
Direct to consumer (DTC) kits are available to buy online.
DTC online testing
In general, these tests do not require any medical input or provide counselling to the purchaser as to the possible pros and cons of testing.
They can be marketed as disease risk assessments and provide a range of information varying from insignificant (eye colour, likelihood of baldness) to life-changing both for the testee and their family.
Genetic kits are available for a range of purposes including paternity testing, looking at ancestry/genealogy, looking for susceptibility and targeted testing.
1. Paternity testing
The pattern of variants is compared between the child and putative parents – a close genetic match would imply a close relationship and statistical tables will guide the report.
An unexpected result could have a negative impact psychologically which is perhaps more likely to bring the patient in to see the primary care physician than the result itself.
Paternity testing is generally not regarded as health-related information, so in the UK is not offered on the NHS. The UK Government has a list of accredited providers of paternity tests for use in court cases and for personal use.
2. Ancestry/genealogy testing
Certain sets of variants will be looked for to give the statistical probability of where a family has come from. This is because, during evolution, a new variant may be found in a population subgroup that has diverted off geographically leading to a unique variant fingerprint for offspring from that ancestry.
Ancestry results can throw up unexpected ethnicity implications since many people will not understand how inheritance can mean variable proportions of your DNA is inherited from each of your ancestors and unexpected paternity issues can be revealed.
3. Recreational genomics
Gives advice on diet, lifestyle, exercise based on an individual’s genetic profile.
4. Susceptibility testing
Looks for common markers that may make a person carrying them more susceptible to disease.
These susceptibility factors may be monogenic or polygenic and may have further complicated interactions with the patient’s environment. We will discuss these issues in more detail in the next section.
5. Targeted testing
Asks if a particular variant is present in the sequenced DNA. It might be used to look for example to see if a particular BRCA1 variant is present which would convey a higher risk than population level of breast, ovarian and prostate cancers.
It might also report on the carrier status of autosomal recessive genes such as those encoding cystic fibrosis variants for use in pre-conception planning. Some of these tests report raw data which needs to be interpreted in terms of risk.
