Scientists have found a link between poor sleep and lowered brain volume.Matthew Purdy/Flickr

Scientists have discovered some new genes that contribute to the onset of Alzheimer's disease.

Making a significant breakthrough in medical history, an international group of researchers reported in Nature Genetics that they have identified 11 new genes associated with Alzheimer's disease, making the total number of genes related to the brain disorder to 21. 

Interestingly, the study has given more insights into the causes of Alzheimer's disease, by re-confirming the role of immune response and inflammation.

Alzheimer's disease is a brain disease that leads to the destruction of memory and other important functions of the brain, including thinking, communication and behaviour. It affects the memory of elderly people above 65 years of age, following which the protein plaques and tangles are formed in the brain, damaging and killing brain cells.

For the study researchers, from the International Genomics Alzheimer's Project, collected DNA data of more than 74,000 people from 15 countries. The data included information about 25,500 Alzheimer's patients and 49,038 people without the disease. The new genes thus identified are: HLA-DRB5/HLA0DRB1, PTK2B, SLC24A4-0RING3, DSG2, INPP5D, MEF2C, NME8, ZCWPW1, CELF1, FERMT2 and CASS4. 

Apart from the 11 new genes, they also discovered another 13 variants. However, further studies are needed to fully confirm their role.

The discovery is expected to help in the development of an effective treatment for the disease. "The discovery of novel pathways is very encouraging considering the limited success of Alzheimer's disease drugs tested so far," researcher Margaret A. Pericak-Vance, said in a news release. "Our findings bring us closer toward identifying new drug targets for Alzheimer's and other neurodegenerative diseases. We'll continue to expand and analyze our data set with this incredible group so that we can better understand the genetic influences on this devastating disease, and find new medical and therapeutic interventions."

Apart from genetic mutations, previous studies have shown that many factors including ageing, head trauma, family history of the disease, unhealthy lifestyle - including  smoking, poor diet and lack of enough exercise, excessive cleanliness and lack of exposure to different kinds of bacteria, viruses and other micro-organisms - increased the risk of developing the disease.