Are Sleep Disorders Genetic?
Learn about how your poor sleeping habits might run in the family
Mar 19th, 2021 •
Are you struggling to find answers about why you’re not sleeping well? If you feel like you’ve tried everything but still can’t seem to catch a break, you might have your genes to blame. Sleep disorders can have a strong genetic component or even a direct genetic cause. However, genetic underpinnings don’t guarantee the development of a sleep disorder. Read on to learn more.
Poor sleep is a world-wide trend now affecting up to one in three individuals. There are many different identifiable sleep disorders that may or may not be connected to our genetic makeup. Common sleep problems like insomnia are often linked to both genetic and environmental factors, but some types of insomnia, along with other sleep disorders, can have a strictly inherited basis.
Research studies on the genetics of sleep disorders started appearing in literature during the 1960s. The question of whether sleep disorders have a purely genetic foundation has been studied in a number of different ways, with a number of different results still forthcoming. Familial studies and twin studies were a natural starting point, and family histories did begin to point towards a genetic link with some types of sleep disorders.
How Your Genes Are Linked to Sleep
Genes can be linked to sleep in a number of ways. They can be directly linked as a causative factor, meaning that an identifiable single gene is causing the sleep disorder. Genes are connected to how much sleep we need, and seem to affect overall sleep patterns.
Related: Neurological mechanisms of sleep
Our genetics create other factors that influence sleep by predisposing us to certain conditions. There are also some genes that correlate to insomnia and sleep deprivation, and these conditions may be triggered given the right circumstances. You can have a genetic predisposition for sleep disorders in general, which may or may not get activated.
There is a 30% chance that if you suffer from insomnia, so does someone else in your family.
The simple answer to the question, “Are sleep disorders genetic?” is yes, sleep disorders can definitely be genetic, but the whole picture is far more complicated. To a degree, the discussion revolves around the question of correlation versus causation: Is there a genetic correlation or is there a direct genetic link?
Related: How sleep works
Correlation is not causation, and it is important to differentiate between the two. Along this line, the nature versus nurture controversy plays a role when examining a given case. Is your sleep disorder definitively caused by genetics? Is it caused by a genetic predisposition that has been triggered environmentally? Is it completely environment and influenced by your lifestyle?
Let’s break it down.
Single Locus Inheritance Patterns
When you look at an individual’s genetic inheritance pattern and there is a single point, a single gene, which can be identified as causing a particular disease or trait, it is called a Mendelian trait. Examples of inherited traits caused by a single gene are eye color, hair color, and blood type. Examples of diseases caused by a single gene include sickle-cell anemia and cystic fibrosis.
Research, through the use of identical twin studies, has identified four rare sleep disorders with a definite single locus, meaning it’s tied to a single gene mutation. It is important to differentiate here between a disease and a disorder. These sleep conditions, although specifically defined in the medical literature, are not diseases. The four sleep disorders caused by a specific gene are:
- Familial advanced sleep phase syndrome (FASPS)
- Chronic primary insomnia
- Narcolepsy with cataplexy
- Fatal familial insomnia
Again, these are rare conditions caused by genetics.
Genes Dictate Sleep Needs
Another aspect of sleep governed by our genetics is how much sleep we need. Be it six hours per night or ten hours per night, this amount is likely an inherited trait. The amount of sleep you need as an individual may well “run in the family” as they say. If you take a look at your parents and siblings, and even grandparents, you may find that everyone sleeps a similar amount.
Genetics and Normal Sleep
We seem to inherit our sleep patterns whether they are typical or unusual. Data derived from studies on monozygotic twins with normal sleep patterns show very similar results. When undergoing sleep studies that assess multi-parametric variables, their polysomnography (the primary measurement test of a sleep study) confirms similar outcomes. They have comparable sleep cycles, rapid eye movement (REM) patterns, and sleep latency (sleep onset) times. This research confirms the genetic connection to sleep patterns in general.
Indirectly, genetics play into our ability to sleep well or have difficulty getting the sleep we need. We can inherit genes that contribute to obesity which is linked to sleep apnea. We can inherit a sensitivity to mold or other allergens that can cause insomnia. Our genes affect our reaction to stress, and an increased stress response can generate into poor sleep or insomnia. In these cases, there is not a specific gene connected to a sleep disorder, but genes that work simultaneously to increase our chances of having sleep difficulties.
Genes have also been linked to the development of secondary conditions. There is a genetic link between insomnia and diabetes, and between insomnia and depression. It is not a given that if you have insomnia you will get diabetes or depression, but if you have the genetic marker you have a much better chance these things will occur.
Genes that Correlate to Sleep Disorders
Research studies have focused a great deal on understanding which genes correlate to various sleep disorders. Genome wide association studies (GWAS) look at large amounts of genetic data to try and link certain genetic codes to particular traits. Recent studies have linked 57 genetic locations to insomnia alone. There are additional genetic code correlates that equate to restless leg syndrome, periodic limb movements disorder (PLMD), and obstructive sleep apnea.
We often hear the terms “genetic predisposition” and “environmental trigger” when it comes to health conditions. You can have a genetic predisposition for obesity, but that does not mean you will become obese. If the right factors are present in the environment then you may indeed become heavy.
This is also the case with genetics and sleep. Aside from the very specific single locus inheritance patterns, where one gene dictates a specific disorder, most of our genetics can only set us up or predispose us to a disorder. The environment then has to work in tandem to create the disorder.
For example, if you have a genetic predisposition for insomnia, and you have a stressful job, and you don’t eat well, and don’t exercise, and watch lots of television before bed, you may well develop insomnia. Conversely, if you have the predisposition, and you make your room a dark quiet sanctuary, turn the TV off hours before bed and read, and eat well and exercise, you may never develop insomnia.
Overall, medical science has proved direct and indirect links between genetics and sleep disorders. When you have a sleep disorder directly associated with a single gene, it is pinpointed as the cause. When genes are indirect, or correlative, you may or may not develop a sleep disorder. In any case, your environment and good sleep hygiene can support better night’s sleep.
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