After a two-stage meta-analysis of 74,046 individuals, researchers were able to discover eleven new genes associated with late-onset Alzheimer’s disease (LOAD). This discovery has effectively doubled the amount of genes that are known to be associated with the disease. The study was an international collaboration headed by the French Institute of Health and Medicine (INSERM), and was published only by Nature Genetics on 27 October 2013.
The first stage involved analyzing the results from four previously-published genome-wide association studies (GWAS). This included genotyping 7,055,881 single nucleotide polymorphisms (SNPs) in 17,008 patients with LOAD, as well as 37,154 control subjects. In the second stage, the team genotyped 11,632 SNPs in 8,572 LOAD patients with 11,312 controls.
When all of the data had been analyzed, there were 19 loci noted with significance of potentially causing Alzheimer’s; 11 of which had not been previously associated. There are now a total of 21 genes that have been linked to the neurodegenerative disease. While mutations on these genes do not guarantee someone will develop Alzheimer’s, it does symbolize an increased risk.
While it still is not clear exactly what causes Alzheimer’s, the results of the study appear to suggest a link with the immune system. Current research is also looking into how cholesterol and large molecules in the brain are dealt with in endocytosis; the process by which cells completely engulf molecules to ingest them. Only after the cause of Alzheimer’s is discovered can research really focus on preventing, treating, or even curing this incredibly complex disease through lifestyle changes, genetic therapies, and/or new medications.