Genetic background of insomnia: At least partially
Last Updated on June 20, 2017 by Joseph Gut – thasso
June 20, 2017 – Insomnia is one of the most common complaint people have about their health. In contrast to common belief and often assumed by the affected sufferers, however, insomnia seems not to be just all in the patients head. A large genome wide association study (GWAS), an international team of researchers has identified, for the first time, seven risk genes for insomnia. This comprises an important step towards the unravelling of the possibly
complex biological mechanisms that predispose individuals to insomnia and indicates that insomnia is not a purely psychological condition.
The research in a large cohort of 113,006 individuals phenotyped as insomniacs revealed 7 genes associated with insomnia. These genes play roles in the regulation of transcription, the process where DNA is read in order to make an RNA copy of it, and in exocytosis, the release of molecules by cells in order to communicate with their environment. Very interestingly and strikingly, one of the identified genes, the homeobox gene MEIS1, has previously been related to two other sleep disorders: Periodic Limb Movements of Sleep (PLMS) and Restless Legs Syndrome (RLS). The researchers concluded that genetic variants in the gene seem to contribute to all three disorders. PLMS and RLS are characterized by restless movement and sensation, respectively, whereas insomnia is characterized mainly by a restless stream of consciousness.
The researchers also found a strong genetic overlap with other traits, such as anxiety disorders, depression and neuroticism, and low subjective wellbeing, which in itself is an interesting finding, because in people’s real life, these characteristics tend to go hand in hand with insomnia. There appears, however, still some more research needed to fully understand the interactions between these characteristics, and the contributions of environmental and social genetic factors to these interactions.
The researchers also studied whether the same genetic variants were important for men and women. Some of the genetic variants turned out to be different, suggesting that, for some part, different biological mechanisms may lead to insomnia in men and women. The researchers also found a difference between men and women in terms of prevalence: in the sample cohort studied, including mainly people older than fifty years, 33% of the women reported to suffer from insomnia. For men this was 24%.
The study was published in the journal Nature Genetics.