RT Journal Article SR Electronic T1 CYP19 haplotypes increase risk for Alzheimer’s disease JF Journal of Medical Genetics JO J Med Genet FD BMJ Publishing Group Ltd SP e42 OP e42 DO 10.1136/jmg.2005.039461 VO 43 IS 8 A1 R Huang A1 S E Poduslo YR 2006 UL http://jmg.bmj.com/content/43/8/e42.abstract AB Cytochrome P450 aromatase, an enzyme that catalyses the conversion of androgens to oestrogen, is expressed at high levels in the gonads and in the brain. Aromatase activity is increased in the nucleus basalis of Meynert during aging and in Alzheimer’s disease (AD), making the gene (CYP19), at 15q21.1, a potential candidate risk factor.We examined 18 single nucleotide polymorphisms spanning the 5′-untranslated region and the entire coding region of CYP19 in 227 patients with AD and 131 control spouses.We found that the gene region could be divided into two haplotype blocks; a haplotype in block 1 and a haplotype in block 2 increased the risk of developing the disease by twofold in APOE 4 carriers. The implication of two haplotypes conferring increased risk for AD warrants further investigation of the regulation of aromatase activity in brain.