Apo E genotypes and risk of dementia in Down syndrome

The relationship between apo E genotypes and risk of dementia in Down syndr ome is not clear, Accordingly, we have analysed this locus in 20 demented a nd 25 nondemented individuals with Down syndrome and combined these data wi th other studies in a meta-analysis. The meta-analysis revealed an estimate d odds ratio for dementia of 2.74 (95% CI 1.34-5.58) (P = .0004) for apo ep silon 4 carriers compared with apo epsilon 3/epsilon 3, Similar to that obs erved in late-onset Alzheimer's disease. An additional parallel with late-o nset Alzheimer's disease was shown by the ape: epsilon 2 allele, which was associated with decreased dementia risk in Down syndrome (odds ratio for ap o epsilon 2/epsilon 2 + epsilon 2/epsilon 3 = 0.37 (95% CI 0.14-0.96)). Thu s, apo E genotypes are associated with similar risk effects in Down syndrom e dementia and late-onset Alzheimer's disease. Am. J. Med, Genet, (Neuropsy chiatr, Genet,) 88:344-347, 1999, (C) 1999 Wiley-Liss, Inc.