Doctors warn against home testing kits for cancer-causing BRCA mutations

Doctors are warning women against using home genetic testing kits because they can give false readings on cancer-causing BRCA mutations commonly found in Jewish populations.

In one case, a consumer testing kit told a woman that she carried the genetic mutation which makes breast or ovarian cancer highly likely. She scheduled preventive breast-removal surgery, which was only called off at the very last minute after NHS clinicians discovered that the kit’s reading was a false positive.

Prof Anneke Lucassen, a geneticist at Southampton University and chair of the British Society for Genetic Medicine, described the woman’s experience as “terrifying,” adding that the tests were “more often wrong than right”.

The steep fall in the cost of genetic analysis, together with the slowness of legislators to regulate in this relatively new field, has led to a proliferation of companies offering to reveal a person’s genetic secrets for as little as £20.

However, a major commercial DNA chip was recently found to be correct in just 17 percent of cases when detecting the BRCA mutation, and missed more than half of those with actual BRCA mutations, from a data-set of nearly 50,000 people.

Breast cancer is a particular concern in the Jewish community, where one in eight Jewish Ashkenazi women will develop it during the course of their lifetime – a far higher percentage than the national average. Recent studies show that Sephardi Jews may also be genetically predisposed to hereditary breast and ovarian cancer.

More women are now choosing to perform prophylactic breast removal after discovering that they have the BRCA gene, to reduce their chances of breast cancer. This is when a woman has an elective mastectomy by way of prevention.