Gene mutation may cause longer circadian cycle and “night owl” behavior.
For those who struggle out of bed in the morning because they like to stay up late, science may have an answer.
A genetic mutation may be the reason for night owl tendencies, according to researchers at the Rockefeller University.
Senior author Michael W. Young, PhD, commented in a press release, “Compared to other mutations that have been linked to sleep disorders in just single families worldwide, this is a fairly impactful genetic change.”
Dr. Young is a geneticist, professor at Rockefeller University and head of the university’s Laboratory of Genetics.
The typical night owl (the condition is known as delayed sleep phase disorder in the medical world) has a delayed sleep cycle. Night owls have higher energy in the late evening and early nighttime hours but would also prefer to sleep later in the morning. However, the rest of the world runs on a different clock, which can lead night owls to suffer chronic fatigue from rising early.
Previous research in Dr. Young’s laboratory has identified a number of genes that affect sleep and other metabolic processes like appetite. Dr. Young and first author Alina Patke were studying subjects at Weill Cornell Medical College when they noticed one subject who stayed up late and had a sleep cycle about 30 minutes longer than average.
Further investigation revealed the subject’s melatonin levels didn’t start to rise until about 2 AM. In most people, melatonin – which is a hormone that promotes sleep – begins to rise around 9 PM.
DNA from the patient showed a variation in CRY1, a gene already shown to be connected to the circadian cycle. Further investigation revealed five family members who shared the gene variation and also had sleep problems.
After extensive analysis of databases from around the world the team found more people who had both the CRY1 mutation and sleep problems. They estimate this mutation may occur in as many as one in 75 people.
Dr. Young and team are now looking at ways to help people with this problem. So far, they report that exposure to strong light upon awakening seems to help.
The study was published in the April issue of Cell.
Information on study funding and conflict of interest was not available.