Question:
The APOE4 carriers also get Alzheimers sooner.

So what is this gene? Is anything known about what it does?

http://www.nytimes.com/library/national/science/health/081700hth-aging-alzheimers.html Excerpt:Everyone has two copies of APOE. Previous research has shown that peoplewith two copies of APOE4 have a 91 percent chance of eventuallydeveloping Alzheimer's. The rate is 20 percent when people have twocopies of APOE3 and 47 percent among those with one copy of each form,said Bookheimer.

Answer: APOs (apolipoproteins) are the protein portions of lipoproteins. ie theblood consituents which carry cholesterol, LDL, HDL, VLDL, etc. APOscome in at least 5 varieties (A-E) presumably made by different genes.And, of course each of the genes have different alleles which is what isbeing referred to in the Alzheimers article (which I read somewhere manymonths ago).

The distribution of the APOs characterizes the type of lipoprotein.

APOA is in HDL and chylomicronsThere is also four kinds of A (I-IV)APOB is in LDL, VLDL, IDL and chylomicronsB-100 and B-48APOC is in VLDL, HDL and chylomicronsThree kinds I-IIIAPOD is a subfraction of HDLAPOE is in VLDL, HDL, and chylomicronsIt is the sole protein found in HDLc and is present in excess inpatients with type III hyperlipoproteinemia. It is the ligand for thechylomicron and LDL receptor in the liver.

Whether this helps you or not I do not know.