MTNR1B
Description of Mtnr1b
Mtnr1b, also known as melatonin receptor 1B, is a protein that plays a crucial role in regulating various physiological processes in the body, particularly those related to sleep-wake cycles and circadian rhythms. It is primarily expressed in the suprachiasmatic nucleus (SCN) of the hypothalamus, which serves as the body's master clock.
Mtnr1b is a G protein-coupled receptor (GPCR) that binds to melatonin, a hormone produced by the pineal gland in response to darkness. Upon binding, Mtnr1b initiates a signaling cascade that influences the expression of clock genes, thereby regulating circadian rhythms.
Associated Diseases
Dysregulation of Mtnr1b has been linked to several disorders, including:
- Delayed sleep-wake phase disorder (DSWPD): Individuals with DSWPD have difficulty falling asleep and waking up at socially acceptable times, often due to a misalignment between their internal clock and the external environment. This condition is often associated with mutations or polymorphisms in the Mtnr1b gene.
- Advanced sleep-wake phase disorder (ASWPD): In contrast to DSWPD, ASWPD involves difficulty staying awake in the evening and waking up at a reasonable hour in the morning. It has also been linked to genetic variations in Mtnr1b.
- Non-24-hour sleep-wake disorder (N24SWD): This rare condition is characterized by a sleep-wake cycle that is longer or shorter than 24 hours. It is often associated with mutations in Mtnr1b that affect its function or expression.
- Seasonal affective disorder (SAD): SAD is a type of depression that occurs during the winter months when daylight hours are shorter. Reduced melatonin secretion and impaired Mtnr1b signaling have been implicated in the development of SAD.
Did you Know ?
Approximately 1 in 5 individuals worldwide suffers from some form of circadian rhythm disorder, with DSWPD being the most common. Mutations in the Mtnr1b gene are estimated to be present in up to 10% of DSWPD cases.
