DEC2 gene: Mutation that causes short sleep

Most people need around 8 hours of sleep for optimal health. Consistently short nights are hard on the body and leave you vulnerable to infection, inflammation, and chronic health problems.

But this website is all about personalization and getting away from stock advice! So let’s dig into one genetic variant that decreases the amount of sleep a person needs.

Sleep duration and the DEC2 / BHLHE41 gene:

I always find the outliers interesting. The people with genetic variants that cause a deviation from the norm – like people with longevity variants.

It turns out that there is a genetic mutation that causes some people to need about an hour and a half less sleep each night. People with the mutation average 6 to 6.5 hours of sleep. The kicker is that there are no known negative effects from this! Imagine – over the course of a year that would be almost 550 hours not spent sleeping. You could take up a new hobby, read dozens of more books, learn a foreign language — or just have more fun.

DEC2, BHLHE41 gene:

The DEC2 gene encodes a protein that affects the gene transcription of core circadian rhythm genes.[ref]

Another name for DEC2 is BHLHE41 (the official gene name).[ref]

Your circadian rhythm is the built-in 24-hour clock that controls the function of lots of things in your body. In addition to impacting your need for sleep at night, the core circadian clock controls when your immune system is most active, how hormones are released over the course of a day, and your body temperature. In fact, your circadian rhythm controls the expression of about 40% of genes in the body.

In addition to its role in circadian rhythm, older research points to BHLHE41 (DEC2) being important in immune response and cancer prevention, although this may also relate to circadian rhythm.

Recently, researchers found that BHLHE41 also impacts orexin levels. Orexin is is a hormone that acts in the hypothalamus to cause wakefulness as well as impacting mood, appetite, and reward. Problems in the orexin system are what causes narcolepsy.[ref]

Genetic Variants: Check your DEC2 gene in 23andMe or AncestryDNA

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BHLHE41 (DEC2) gene:

Check your genetic data for rs121912617 P385R (23andMe v5; AncestryDNA):

  • G/G: typical
  • G/T: natural short sleeper (0.5% of population)[ref]
  • T/T: natural short sleeper (really, really rare)

Members: Your genotype for rs121912617 is .

Are there other genetic mutations that cause short sleep? Another rare DEC2 mutation has been found by researchers. It is known as Tyr362His and does not have an rs id number yet.[ref]

Researchers also recently found a rare mutation in the ARDB1 gene that also seems to cause naturally shorter sleep.[ref] This rare mutation does not seem to be covered in 23andMe or AncestryDNA data.

The key takeaway here is that mutations that cause short sleep are rare, but they do exist.


If you are in the 0.5% of the population with this DEC2 mutation, then you can stop worrying about why you don’t need 8 hours of sleep :-)

For the rest of us, prioritizing 7.5 to 8 hours of sleep is important.

Here are some sleep tips:

  1. Block blue light from electronics at night for several hours before bed.
  2. Turn down the bright overhead light. Consider switching to lamps with bulbs that give off a yellow or orange light.
  3. Sleep in a cool, dark room.
  4. Blackout curtains are a must if you live in an urban area with light pollution.
  5. Get out in the sunshine or bright light in the morning after you get up.
  6. If you are a slow caffeine metabolizer, cut off caffeine by noon.

Boosting orexin:

The research on orexin and the DEC2 mutation is interesting. Boosting orexin should lead to shorter sleep. Research points to several ways to boost orexin levels by a bit (not as much as the DEC2 mutants):

Get out in the sunlight: Animal studies show that exposure to sunlight increases orexin.[ref]

Decrease carbs at night: A drop in glucose levels stimulates orexin.[ref][ref] Going low-carb may prompt an increase in orexin, at least temporarily.
Something to experiment with: Eat dinner early or avoid carbs with dinner and see how it impacts your natural sleep requirement.

Go keto: A ketogenic diet increases orexin-A levels.[ref] (This may be why some people have trouble sleeping initially when going low-carb.)

Use common sense: Increasing orexin in order to sleep less may not be the best idea. Sometimes sleeping 7.5 – 8 hours a night really is the best thing for your mental and physical health.


Related Articles and Topics:

Increased Slow Wave Sleep:
A genetic variant in the ADA gene causes people to typically have more deep, slow-wave sleep.

Sleep Report:
A quick overview of how your genetic variants impact various aspects of sleep including insomnia, circadian rhythm, and sleep quality.

Depression, Genetics, and Circadian Rhythm:
Your genetic variants in your circadian rhythm genes impact your susceptibility to depression, anxiety, and bipolar disorder.

Author Information:   Debbie Moon
Debbie Moon is the founder of Genetic Lifehacks. She holds a Master of Science in Biological Sciences from Clemson University and an undergraduate degree in engineering from Colorado School of Mines. Debbie is a science communicator who is passionate about explaining evidence-based health information. Her goal with Genetic Lifehacks is to bridge the gap between the research hidden in scientific journals and everyone's ability to use that information. To contact Debbie, visit the contact page.