23andMe currently uses a genotyping chip, not gene sequencing. So, this article is misleading at the top (but gets more accurate at the bottom).
Early variant discovery suffers from the winner's curse phenomenon: we overestimate the effect of newly discovered mutations.
As time has gone on, it has become clear that even for many Mendelian diseases, the genetic background plays a significant role in terms of who will develop the disease (or how early they will do so). The estimates of "penetrance" have fallen as we have obtained more data.
This affects clinical genetic interpretation as well as the automated stuff that 23andMe is doing.
Early variant discovery suffers from the winner's curse phenomenon: we overestimate the effect of newly discovered mutations.
As time has gone on, it has become clear that even for many Mendelian diseases, the genetic background plays a significant role in terms of who will develop the disease (or how early they will do so). The estimates of "penetrance" have fallen as we have obtained more data.
This affects clinical genetic interpretation as well as the automated stuff that 23andMe is doing.