Some important news this morning in the consumer genetics space: personal genomics company 23andMe has just announced the availability of risk information for Alzheimer's disease using two markers in the APOE gene. The APOE markers have a famously large effect on Alzheimer's risk - the ~1.7% of the population who carry two copies of the ε4 version of the gene are ~11 times more likely than average to develop the disease - but weren't available on previous versions of the 23andMe test. The company's recent upgrade to its v3 chip included a key marker that now allows them to provide APOE predictions to customers - if you bought your kit in either of the last two sales, chances are you'll be able to access this information.

The APOE results are locked - meaning that before being able to view them, customers need to read a brief information page and click a button indicating they understand the implications. Here's a screenshot:

Once you've agreed that you understand, your results appear. Mine are reassuring - I carry two "normal" (ε3) copies of APOE. (I actually already knew this with fairly high confidence thanks to some analysis done by Luke Jostins a few months ago, which we'll be writing about over at Genomes Unzipped shortly.)

The up-front warning and detailed information provided by the company all seems perfectly reasonable to me: intuitive and thorough, without being patronising. You can view the full information provided to 23andMe consumers here.

Customers who bought their tests before the v3 launch will need to upgrade to the new chip to be able to access their APOE results. The previous versions of the chip apparently didn't include one of the key markers (rs429358) because this is difficult to call accurately using the Illumina platform - I'm not sure what has been tweaked to get this marker working on the v3 chip, but I can only assume the company is very confident in its results. A bad APOE prediction would be, to put it mildly, a potential PR disaster for personal genomics (as deCODEme learnt in December 2009).

[Edited to fix inflated risk estimate for ε4/ε4 homozygotes.]