A subsequent study in 2000 patients was unable to replicate any association between 11 SNPs in the SORL1 gene and late onset Alzheimer's disease, but did find a (weak) association with rs2070045.[PMID 17949987] Another study was able to replicate the association between at least some SORL1 SNPs and Alzheimer's disease.[PMID 18090307]
Differences between ethnicities may also be complex with regard to the risk of developing Alzheimer's disease. In a recent study, one SNP (#12) near the 5' region was associated with AD in African American and Hispanic individuals, whereas two SNPs (#26 and #20, respectively) in the 3' region were also associated with AD in African American and non-Hispanic white individuals. Different haplotypes were associated with AD in African American and white individuals, including the TTC haplotypes at SNPs #23-25, as previously published for Caucasians. [PMID 17420311]
Recent evidence has revealed that SORL1 and possibly other genes harbor rare risk variants of intermediate to large effect size for Alzheimer's . In the article 17 variants in SORL1 were found related to Alzheimer's, though further research is necessary . With additional confirmation, SORL1 would become the fourth autosomal Alzheimer gene discovered. 2% of Alzheimer patients are believed to carry a rare SORL1 variant.