A genetic mutation makes some people need less sleep
Though most of us feel the consequences of missing out on a full night’s sleep, a lucky few don’t - thanks to a rare genetic mutation.
According to a study published in Neuron, some people who can function normally on six hours of sleep carry an altered version of a particular gene, making it the second to be associated with short sleep.
In their previous research in 2009, the team found a mother and daughter - who felt rested after about six hours of sleep at night - both had a mutation in a gene called DEC2.
The DEC2 gene codes for a protein that stops other genes from expressing. One of these genes that the protein inhibits controls a hormone called orexin, which is known to regulate wakefulness.
In the follow-up study, the scientists studied another family of naturally short sleepers and have identified another mutation, which they estimate about four in every 100,000 people have.
The scientists engineered mice to have the same mutation and found that they slept, on average, one hour less per day than control mice without the mutation.
For the family of humans with the mutation, they slept an average of two hours less per day than those without the mutation.
The mutated gene, called ADRB1, encodes a receptor for a neural signalling molecule called noradrenaline.
In mouse brains, the cells that had this receptor were active while they were awake and quiet during deep sleep, according to the researchers.
They propose that the mutation makes these neurons more active, which could explain why its human carriers sleep for shorter periods of time.
Though this research has been conducted on small groups, it could pave the way for the development of drugs that target these kinds of mutations or help those with sleeping disorders feel better while getting little sleep.