Alzheimer’s linked to New Gene

An Icelandic team of scientists analysed the genomes of over 2,000 Icelanders and identified a gene mutation that increased the risk of the disease by approximately three times. At University College London, a separate team discovered the same mutation whilst analysing the genomes of sufferers of the disease. Professor John Hardy, who was part of the team at UCL, told UCL News “thanks to new advances in technology it’s now possible to get a much more detailed look at the genetic risk for Alzheimer’s, picking up rare variants like this one that were previously impossible to identify,” which was definitely the case for the discovery of this particular gene mutation.

The gene in question is the TREM2 gene, whose encoded protein is expressed in the microglia in the brain. Microglial cells are the brain’s macrophages and act as the primary immune defence in the central nervous system (CNS). They are primarily scavenger cells that remove cellular debris from sites of injury, but also react quickly to infectious agents introduced to the brain, decreasing inflammation and destroying the intruders before they do any damage. The TREM2 protein regulates the process by which these microglial cells engulf cell debris. Professor John Hardy of UCL says the intact gene acts as a protective mechanism and those with the mutation are living life without a “safety net.”

Alzheimer’s is a neurodegenerative disorder, with no clear known cause or cure present. It is the most common cause of dementia, a group of symptoms associated with a decline in brain functions, affecting memory and behaviour. Despite the unknown cause of Alzheimer’s disease, sufferers have been found to have abnormal amounts of protein (plaques) in the brain. These plaques reduce the ability of healthy neurons to carry messages to and from the brain, gradually destroying them. This damage eventually spreads to other areas of the brain, impairing brain function. Dementia is a disease affecting a large number of the population in the UK, and this research could help as new treatments are developed.

The findings from these two studies of the TREM2 protein suggest that, in the brains of the people with the neurodegenerative disorder, these cells are unable to clear away the plaques that are the hallmarks of the disease, and so effectively boost the risk of the disease. Dr. Guerreiro told UCL news that, “the more we can understand about the causes of Alzheimer’s, the better our chances of developing treatments that could stop the disease developing,” and certainly the discovery of this gene mutation could be a step forward in understanding this devastating affliction.