Abstract
Clock genes are active in many parts of the brain. Their function is based on a negative feedback time loop.
CLOCK, NPAS2, CRY and PER genes belong to the most important circadian ones. The primary center of chronobiology is suprachiasmatic nucleus in hypothalamus.
It orchestrates all other circadian centers in the body via neural and paracrine ways. In the end, e.g. melatonin or glucocorticoid secretion, activity/rest rhythm or body temperature are regulated.
Mental disorders are supposed to be based on dysregulation of peripheral circadian oscillators. Polymorphisms in circadian genes are recently studied e.g. in Alzheimer´s dementia, substance abuse, psychotic disorders, mood disorders, anxiety disorders and autism.
There is a trend to involve more polymorphisms and genes into each study, which is due to recent advancements in genetics. The CLOCK gene seems to be important in etiology of Alzheimer´s dementia.
SIRT1 gene polymorphisms were associated with schizophrenia. In bipolar disorder, the CLOCK and VIP genes were recently revealed as the most important.
A better knowledge on the role of circadian genes and their abnormalities in mental disorders will contribute to a better treatment of our patients.