Restless leg syndrome (RLS) has a strong genetic component. In studies of people whose RLS has no other identifiable cause, up to 92% report a family history of the condition. If you have a sibling with RLS, your risk is roughly 3.6 times higher than the general population’s. The condition doesn’t follow a simple one-gene inheritance pattern, though. It’s driven by the combined effects of many genes, each contributing a small amount of risk, layered on top of environmental and lifestyle factors.
How Strong Is the Family Link?
The familial clustering of RLS is one of the most consistent findings in sleep medicine research. A large family study from Quebec found that 77% of RLS cases were familial, meaning the affected person had at least one relative with the same condition. Siblings of someone with RLS faced a relative risk of 3.6, while offspring had a relative risk of 1.8.
The strength of the genetic connection depends on the type of RLS. When RLS appears on its own, without an underlying trigger like nerve damage or kidney disease, genetics plays a dominant role. In one study of 54 patients, 92% of those with this “primary” form had affected family members. By contrast, only 13% of those whose RLS was tied to peripheral neuropathy reported a family history. So if your RLS showed up without an obvious medical cause, the odds that genetics is involved are high.
Early Onset Points to Stronger Inheritance
People who develop RLS symptoms at a younger age tend to have the strongest genetic loading. Research has shown that among patients with early-onset RLS, as many as 60% of their first-degree relatives (parents, siblings, children) and 50% of their second-degree relatives (grandparents, aunts, uncles) are also affected. Those are striking numbers, far higher than you’d expect by chance.
Late-onset RLS, which typically appears after age 40 or 50, is more likely to involve other contributing factors like iron deficiency, medication side effects, or chronic disease. Genetics may still play a role in these cases, but it tends to share the stage with other triggers.
The Genes Involved
RLS is not caused by a single gene. The largest genetic study to date, a 2024 meta-analysis published in Nature Genetics, identified 164 locations across the genome that influence RLS risk, including three on the X chromosome. That’s an eightfold increase over what was known just a few years earlier, and it confirms that RLS is a genuinely polygenic condition, meaning many genes each contribute a small piece of the overall risk.
Three genes identified in the earliest genome-wide studies remain the most well-established contributors. MEIS1, which encodes a protein that helps regulate how other genes are turned on and off, carries the strongest known effect in people of European descent. The risk version of this gene is associated with lower production of the MEIS1 protein, and researchers have found that MEIS1 directly controls the activity of another RLS-linked gene called SKOR1. When MEIS1 output drops, SKOR1 expression changes with it, creating a cascade that appears to affect brain development and function.
BTBD9 is the gene most clearly tied to iron metabolism, one of the key biological pathways in RLS. The risk variant of BTBD9 is associated with lower levels of ferritin, the body’s main iron storage protein. Animal studies show that lower expression of this gene correlates with lower iron concentrations in the brain region that produces dopamine. This connection helps explain one of the central puzzles of RLS: why a movement disorder responds to iron supplementation in some patients.
It’s Polygenic, Not Simple Inheritance
If RLS ran in families like a textbook dominant trait, you’d expect roughly half of a patient’s children to develop it. The actual pattern is messier. Some families have rates well above 50%, while others see the condition skip generations or appear sporadically. This is the hallmark of a complex genetic trait, where dozens or hundreds of gene variants, each with a tiny effect, combine to push someone above or below a risk threshold.
The 2024 meta-analysis identified 193 independent genetic signals across those 164 risk locations. Machine learning models that combined genetic data with nongenetic information (like age, sex, and other health factors) were able to predict RLS status with an accuracy score between 0.82 and 0.91 on a 0-to-1 scale. That’s a strong signal, but it also means genetics alone doesn’t tell the whole story. Environmental factors, iron status, and other health conditions fill in the gaps.
Notably, sex-specific analysis found that men and women share nearly identical genetic susceptibility to RLS, with a genetic correlation of 0.96. The fact that RLS is diagnosed more often in women likely reflects hormonal or other nongenetic influences rather than differences in inherited risk.
Genetic Risk Varies by Ethnicity
RLS is more commonly diagnosed in people of European descent, and part of that difference is genetic. The specific risk variants, and how common they are, differ across populations. In people of European ancestry, MEIS1 is the strongest genetic risk factor. In Asian populations, variants in BTBD9 and a gene called UTRN carry more weight, while MEIS1 plays a smaller role.
A systematic review found that risk-increasing gene variants in Asian populations raised the odds of RLS by 1.2 to 2.8 times, while variants in European populations increased odds by 1.1 to 1.9 times. The overlap is partial: BTBD9 and SKOR1 appear on both lists, but each population also carries unique risk markers. This means a genetic risk profile developed in one population won’t perfectly predict risk in another.
What This Means If RLS Runs in Your Family
Having a parent or sibling with RLS doesn’t guarantee you’ll develop it, but it does meaningfully increase your chances. The more relatives you have with the condition, and the younger their symptoms started, the stronger the genetic signal. If you’re already experiencing the characteristic urge to move your legs at rest, a family history makes it more likely that your symptoms are RLS rather than something else.
Because many of the implicated genes affect iron handling in the brain, paying attention to your iron status is especially relevant if you have a family history. Low ferritin levels are common in people with RLS and can worsen symptoms even when they aren’t low enough to cause anemia. The genetic link to glutamate receptors, flagged in the 2024 meta-analysis, has also opened new avenues for treatment, with researchers identifying several of the implicated gene products as potential drug targets.
One additional finding from recent genetic research: a statistical method called Mendelian randomization indicated that RLS itself may be a causal risk factor for diabetes. This doesn’t mean every person with RLS will develop diabetes, but it suggests the conditions share biological pathways, and managing RLS may have benefits beyond symptom relief.