Memory in Adults Impacted by Versions of Four Genes

Two studies have been done, led by Charles DeCarli, which may help prevent Alzheimer’s disease from occurring. In the first study, the hippocampus was targeted for the cause of memory loss because it shrinks as a person gets older. The gene variant that was identified caused the hippocampus to not have a defense against memory loss, which caused destruction and shrinkage. The risk of Alzheimer’s doubles every five years starting at the age of sixty-five. The gene that was identified as the main reason for shrinking were genes involved in maturation of the hippocampus and apoptosis, or cell death. By studying the normal regulations of the proteins causing hippocampus shrinkage, researchers are hoping to stop premature shrinkage. Different versions of a gene usually come down to changes in just one of the tens of thousands of DNA "letters" that make up genes. These one-letter differences are known as single-nucleotide polymorphisms, or SNPs. The experiment involved 9,232 dementia-free people over 67. The experiment showed four different genes that coded for hippocampus shrinkage. One gene, rs7294919, was strongly linked to hippocampus decline and health. In the second experiment, was aimed to deal with intracranial volume, which is an indirect measure of the size of the brain at full development. The experiment involved 8,175 elderly people. As a result, there was no association with brain volume. Though, they did discover that intracranial volume was associated with two loci: rs4273712, a known height locus on chromosome 6q22, and rs9915547, tagging the inversion on chromosome 17q21. Using these two studies, researchers hope to delay memory loss in older people, and reduce the number of Alzheimer’s cases.