23andMe: 23notMe, not yet

29 09 2008

23andme cheeper

The company 23andMe was in the news thrice this month:

  1. cutting the price of its service by more than a half
  2. organizing a celebrity spit party
  3. the husband of the 23andMe co-founder Anne Wojcicki, better known as Google co-Founder Sergey Brin, revealed he is at risk for Parkinson’s Disease, as determined by….23andMe.

Coincidence or part of a strategic plan?

23andMe is a ‘direct to consumer genetic testing’ company that as 23andMe puts it: “democratizes personal genetics”. The lowering of the service price from $999 to $399 brings personalized genomics within the range of many.

What do you get for those $399? A spit kit, you do your thing, send the tube to a certified lab, which analyzes your saliva for more than a half-million points (called SNPs) scattered across the 23 pairs of chromosomes you have (hence 23andMe), as well as your mitochondrial DNA. 23andMe shows the digital data and gives you information on certain traits and diseases. 23andMe also gives information on your ancestry and compares your DNA to your relative’s and friend’s-genes, if you want to share that knowledge with them. With your genes in their database you help 23andMe to perform more research for new discoveries, a program called 23andWe. In fact once you sign up you cannot refuse the use your (anonymous) DNA for this purpose.

The main question is: what purpose does this serve (besides as a potential for yielding income)?

According to 23andMe the main purpose is ‘for research’, ‘for education’ and ‘for fun’: “It’s fun to learn about your own genome”.

In this light, we should probably see the recent event 23andMe organized: a spit party where a few hundred people were lured away from the catwalks during the Fashion Week in New York City. On the sound track of “a whole lot of love” celebrities were spitting their DNA-containing saliva in a tube (see here and here). According Guy Kawasaki, who report on it on his blog (see here),

“even Goldie Hawn and Kurt Russell were there providing their spit, but their handlers wouldn’t let me take a picture. I found this ironical: Giving DNA was okay but not a picture.”

The aim for which Sergey Brin let 23andMe test his DNA was less funny. As Sergey (whos mother has Parkinson) explains in his brand new blog:

(…..) Nonetheless it is clear that I have a markedly higher chance of developing Parkinson’s in my lifetime than the average person. In fact, it is somewhere between 20% to 80% depending on the study and how you measure. At the same time, research into LRRK2 looks intriguing (both for LRRK2 carriers and potentially for others).

Thus this shows a 3rd aim: diagnostic?!
Formally 23andMe denies there is a diagnostic purpose (in part, surely, because the company doesn’t want to antagonize the FDA, which strictly regulates diagnostic testing for disease). However, 23andme does give information on your risk profile for certain diseases, including Parkinson.

In addition, 23andMe encourages the formation of networks of people sharing the same traits.

“If you want to have a community around psoriasis,” Ms Wojcicki said, “we’d like to be able to allow you to form a psoriasis-specific community.” (see New York Times article)

Psoriasis-specific community when you only have the genes that may enhance the risk of getting psoriasis??

That sounds like condemning you to a psoriasis patient already?!

Then lets discuss the following burning question: how well does 23andMe predict that you will get the disease?

Even the LRRK2-gene data of Mr. Brin aren’t that conclusive. A marked higher chance of 20% to 80% is often misconceived as meaning that Sergey’s chance of getting Parkison is 20-80%, or “he will almost get the disease for sure”. As explained by the Gene Sherpa in his excellent post on this subject (see here) it only means that the LRRK2-mutation increases the normal chance of Americans/Europeans getting Parkinson from 2-5% to 4-10% at the most (the chance is less than doubled). Furthermore LRRK2 isn’t the most crucial gene for getting Parkinson.

23andMe has chosen to relate personal health info only to common diseases and common genes. Thus whether you have an enhanced or lowered risk for breast cancer (normal 1 out of 8 women) is determined by 2 (not very predictive) SNPs associated with Breast Cancer, but not by determining BRCA1/2 mutations that are highly predictive for breast cancer, but rare in the entire (western) population .

Although 24andMe explicitly mentions that the tests are for non-diagnostic purposes, it is hard to imagine that people will see it otherwise. But:

  • Most genes are only weakly predisposing
  • Often multiple genes are working in concert in a difficult to predict way (seldom one gene-one disease)
  • The environment and chance also play an important role.

Thus the value of these fun predictions is low, but how does it affect people that think they are prone to having a disease? For some it might be reason to adjust their lifestyle (but then, what is the chance you really change “your destiny”), others may get fixed on their presumptive future disease, confused, or depressed. It is not without reason that genetic screening is usually restricted to people with high risks, when a disease can be predicted accurately (without too many false positives and negatives), something can be done about it (prevention or treatment), and only as part of a genetic consultation by professionals.

Sources; further reading