Instead of examining the entire BRCA gene, 23andMe’s breast cancer screen looks at just a handful of places in the gene where mutations are known to appear. Meanwhile, there are more than 1,000 other BRCA mutations that contribute to your breast cancer risk. The 23andMe test doesn’t look for any of them. That makes it difficult to draw conclusions from the 23andMe BRCA test. Just because you test negative for the few mutations that 23andMe screens for doesn’t mean that you won’t get breast cancer.

Source: New York Times February 02, 2019 01:02 UTC