Researchers have found a gene mutation that could help explain the “night owl” behavior which is a type of insomnia. If you suffer from it, you know it well, the inability to fall asleep before late at night leaving you groggy in the morning.
This gene variant disrupts the circadian clock — our internal clock which regulates our sleep and wake cycles — causing sleeping patterns disruption and late sleep onset in people with this gene mutation.
Our natural internal clock controls our biological processes such as the release of certain hormones which influence sleepiness and alertness rhythms in our body. If this process is corrupted, it can lead to different sleep disorders including narcolepsy and chronic insomnia.
One of these sleep disorders is called delayed sleep phase disorder (DSPD) and can manifest itself by an inaptitude to fall asleep before the wee hours of the night. People with DSPD have been found to have a desynchronized circadian clock disturbing the release of the sleep hormone — melatonin.
When examining the melatonin levels of a DSPD patient, researchers discovered that the release of melatonin in her body was delayed by a constant amount of time. “Melatonin levels start to rise around nine or 10 at night in most people,” explains Michael W. Young, senior author on the Rockefeller University study. “In this DSPD patient that doesn’t happen until two or three in the morning.”
After sequencing the patient’s DNA, researchers found a specific mutation in one of her genes — called CYR1 (cryptochrome circadian clock 1) — which has already been found to be related to the circadian clock. This mutation was shown to partially inhibit the production of sleep hormones.
After studying 70 individuals of which 38 were carrying the genetic variant, the researchers found that those carrying this gene mutation displayed delays in the onset of sleep. The thirty-eight participants with the mutated gene all reported some form of sleep disruption.
“Carriers of the mutation have longer days than the planet gives them, so they are essentially playing catch-up for their entire lives,” said lead co-author Dr. Alina Patke.
The study was published in the April 6 issue of the journal Cell.