The butyrylcholinesterase K variant is a protective factor for sporadic Alzheimer's disease in women

Introduction - Recent reports indicate that the K variant of the butyrylcho linesterase (BCHE) gene may act in synergism with the epsilon (4) allele of apolipoprotein E (APOE) to increase the risk of Alzheimer's disease (AD), but this is controversial. Material and methods - We genotyped for the BCHE -K and APOE epsilon (4) alleles in a sample of 249 AD patients and 250 cont rols derived from the same region in a Spanish population. Results - A prot ective effect of the K variant of BCHE with an odds ratio of 0.41 (95% conf idence interval 0.19-0.86, P = 0.02) was observed among non-APOE epsilon (4 ) carriers, but it was limited to women. Conclusion - Our study is the firs t to demonstrate that lower susceptibility to AD determined by the K varian t of BCHE is dependent on gender.