Variations in Biological Clock Genes May Increase Risk of MS, Study Reports

Variations in Biological Clock Genes May Increase Risk of MS, Study Reports

Researchers have found a link between variations in two genes that control our 24-hour biological clock and the risk of a person developing multiple sclerosis.

The study, “Association of circadian rhythm genes ARNTL/BMAL1 and CLOCK with multiple sclerosis,” was published in the journal PLOS ONE.

Scientists know MS is less prevalent closer to the equator, such as in South America, Asia and sub-Saharan Africa, than in regions far to the north or south of it. The far-flung areas include Canada, the northern United States, northern Europe, and southern Australia.

The reasons behind this geographical association are unclear, although scientists know that low vitamin D levels, which stem from less sunshine, are a risk factor for MS.

A team of researchers wondered if different geographical locations, with their light and temperature differences, could influence the risk of MS by affecting our biological clock.

This clock, which scientists call our circadian rhythm, is a crucial part of our physiology. It controls our  sleeping and waking patterns, for example. And light and temperature play a major role in it.

Scientists say the clock runs our brain and organs, adjusting our hormones, behavior, cognition, metabolism and immune system to the time of day.

One measure of the circadian rhythm’s importance is that it exists not only in humans but in many living things.

When the circadian rhythm is disturbed — for instance, when a person works a night shift — it can increase the risk of a health disorder. In fact, the risk of MS is higher among people working shifts, especially if they started when they were younger than 20 years old, research indicates.

And a recent study demonstrated that disrupting the circadian rhythm of a mouse model of MS led to a more severe progression of the disease.

Researchers decided to explore the link between circadian rhythm and MS at the genetic level. They looked for variations in genes at the core of our circadian clock.

The study included 900 MS patients and 1,024 healthy controls, all of Slavic origin — Slovenians, Croatians, and Serbs. The team analyzed DNA extracted from their blood for variations in the biological clock genes CLOCK and ARNTL.

They discovered that the rs3789327 variation in the CLOCK gene and the rs6811520 variation in the ARNTL gene significantly increased the risk of women developing MS, although it had no correlation with men.

In addition, the association between the ARNTL variation and risk applied only to patients with relapsing-remitting MS, and not with other types.

Taken together, the results pointed to a link between disturbances in circadian rhythm and development of MS.

The team said disrupting the circadian rhythm may alter “daily cellular molecular metabolic mechanisms and therefore contribute to neurodegeneration on a long-term basis.”

“Since cellular metabolic mechanisms are related not specifically to neurodegeneration but to all states of health and disease, circadian rhythms are an important mechanism to be studied in chronic diseases,” they concluded.



  1. Cheryl Boissy says:

    Hmmmm! I was born, raised and live in New England. And, from age 18 – 23, I worked night shift at a hospital during summer months, thereby interrupting circadian rhythm. Sleep was awful as the time change was inconsistent.

    • Karen D Bosek says:

      hi Cheryl B, Nice to meet you ;+), my name is Karen B. I hope you are feeling well?. I was born in Detroit MI, and entered this world at night- 2 this day i’m still a ‘Night Owl ‘.I seem to function better. My sleep habits have always been awful, and current, where I have to take sleep med’s. I am 55 of age by the way. I was never a morning person!,and wish the sun would rise @ night LOL.. I was Diag: with RRMS back in 1998- and live in FLA. I appreciate your post, thank you for sharing. My last comment for this eve., is although MS is complicated, I find it VERY HARD to believe that no one has found a CURE for US YET ?. I forgot to mention my first cousin has MS as well, and also born in MI. So, Yes, I am thinking there is a Hereditary issue / Chromosome issue going on as well. Cheryl, can you tell me what med;s are you taking for MS?, and how are you feeling / life/ etc.. Thank you so much. Karen B/ [email protected]/ if you would like to chat?. Have a super day / eve. Karen ~ USA

      • Amber says:

        You know what I’ve noticed with alot people with ms, there’s alot of people that are from Michigan!! Im from Michigan born and raised but moved down to Texas in 2008 and was diagnosed with ms in 2010!!! I read how the vit d has alot to do too and sun light!! Well in michigan, you don’t get a whole lot of sun lol so many questions that will probably never get answered!! I just find it crazy that alot of ms people come out of Michigan!!!

      • Merichel says:

        There certainly is a hereditary issue. There are only few studies about it and they only say that there is a ‘genetic predisposition’. I’ve been looking into this issue a lot because I’ve just been diagnosed and my great grandfather also suffered the disease. He had only one child who only had my mother, so we can’t know for sure if there would have been more people with it in our family if they would have had more children… Thanks for sharing your story. Hope you’re doing as good as possible, and your cousin too.

      • Stacy says:

        I was born in NJ but have lived in FL since I was a toddler. In 36 now and was diagnosed with rrms in 2009.I have had horrible sleeping habits since I was a kid. My first cousin who lives in NJ and is 3 months younger than me was diagnosed in 2011. Crazy!

  2. Sandra Bratcher says:

    Born in Ohio , I have consistently had sleep problems. They have gotten worse with age.
    I was diagnosed in 2005 but told based on medical history , I have had RRMS since at least my teens. I take several meds to be able to sleep.

  3. Linda Comfort says:

    When I was in my early 20s I worked nights. My husband worked days. We had 2 kids. He slept at night when they did. I tried to sleep when they napped etc. At 42 I was diagnosed with MS. We lived in the Milwaukee area. I always lived there till I was 50. I do use a c pap machine at night.

  4. Kimberly Cole says:

    I was born and raised in Orlando, FL. Healthy eater. Excercise often. Got MS at 39, although tested at 31 for it and had no visible signs. I have a son with Trisomy 21. Huh.

  5. Sandra Dennison says:

    I was born in Denver, CO dad was in service traveled all over the world. I was diagnosed with lupus 20 years ago and now it is suspected I had MS instead. I was diagnosed in May 2017 at the age of 59. Been a long hard battle since then. I take Tecfidera and seems to be helping.By the way have lived in Houston 50 years.

  6. Merichel says:

    Very interesting study, tahnks for sharing it. I have some of those factors (worked at night). I’m using now a little dose of melatonin to regulate by biological clock and it seems to start working.

  7. Shannon Bonsey says:

    Born and raised in Maine, worked nights in summer in hospital during my nursing school days at age17-20. Symptoms began after first child at 23 years old. Diagnosis at 27 years—Remitting/Relapsing and I remained very healthy and active for 30+ years despite several relapses, two more children, grad school, two happy marriages, and a productive career. MS did catch up to me and now at 61, my MS has moved to progressive-I need assistance walking+ but so thankful for all the good years. Interesting study. Thank you

  8. Jennifer Michaels says:

    Born at 4am in NC but have always struggled to sleep at night. DNA testing shows 95% Irish genes. Have also battled S.A.D. My entire life. Diagnosed with MS at age 30 in ‘95.

  9. Liz says:

    I was born in California lived there for my first 12 years. Our family moved to Ohio in 73. I’m now 56 and was DX 5 years ago. I’m also a night person. I think it could be the lack of sun for me.

  10. Konstantinos says:

    I was born and raised in Northern Greece (Lat.41). Worked most of my 21 years as a police officer, in shift rotation, starting at 18 years of age. Being also a night person.

  11. Noelle Rogers says:

    I found out that I have RRMS in 2014, I was born in California at night 34 years ago and lived in Georgia and Florida. I always had trouble sleeping do to work or children. I have learned from my grandparents that nobody else in my family has MS. I have to take vitamin D everyday, went through so many MS medications then I found out about the Ocrevus. It has been working out so far I have been taking it for a year now and have had less relapses. Even though I have MS and hurt all the time I still have to stay positive to keep going.

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