KLRG1 rs201449027: Sleep Health Association
rs201449027 is a rare single nucleotide polymorphism mapped to the killer cell lectin-like receptor G1 (KLRG1) genomic region on chromosome 12. Large-scale genomic research has linked this variant to composite principal component measures of multidimensional sleep health. Because research into this locus is still emerging, it represents a trait-associated marker rather than a diagnostic or deterministic health factor.
What each genotype means
Typical sleep health profile
This genotype represents the most common version of this genetic marker in the general population. Research indicates that this variant in the KLRG1 gene is associated with composite measures of sleep health, but the evidence is limited and does not suggest a specific health outcome. You should view this as a normal variation rather than a clinical indicator.
This is the major allele genotype and is found in the vast majority of individuals across all global populations.
Variant sleep health association
Carrying one copy of this variant has been statistically associated with differences in composite sleep health scores in large-scale genetic studies. Because this is a rare variant, the clinical significance of this association remains uncertain and is not currently used to predict individual sleep quality or health. Please consult a sleep specialist if you have concerns regarding your sleep patterns.
This genotype is rare, occurring in less than 1% of the population based on current gnomAD data.
Rare variant sleep association
This genotype represents the rare variant form of this marker, which has been linked to variations in sleep health metrics in research studies. The evidence for this association is limited, and it is not known how this specific genotype influences sleep in a clinical setting. This finding should not be used to diagnose or manage any sleep-related conditions.
This genotype is extremely rare, with a frequency significantly below 1% in most studied populations.
Genomic Location and Genetic Context
The single nucleotide variant rs201449027 is located on chromosome 12 within the genomic neighborhood of the KLRG1 gene. Identified in deep-sequencing and dense imputation datasets, this variant falls into the non-coding genetic architecture surrounding immune-related loci. Unlike major coding mutations that alter amino acid sequences directly, variants in this region typically act as non-coding regulatory marks or tag broad linkage disequilibrium blocks. Because it is cataloged in the National Center for Biotechnology Information (NCBI) dbSNP database and population registries like gnomAD, researchers track it to investigate how variation in non-coding DNA correlates with human phenotypic diversity across large cohorts.
Biological Function of the KLRG1 Gene
The KLRG1 gene encodes killer cell lectin-like receptor G1, a well-characterized transmembrane receptor expressed predominantly on natural killer (NK) cells and memory CD4+ and CD8+ T lymphocytes. In immunology, KLRG1 serves as an inhibitory immune checkpoint receptor and a biological marker of cellular differentiation and replicative senescence. Upon binding to its physiological ligands, such as classical cadherins (E-cadherin and N-cadherin), KLRG1 transmits inhibitory signals through an immunoreceptor tyrosine-based inhibitory motif (ITIM), curtailing immune effector responses and cytokine release. While its canonical role lies in regulating adaptive and innate immunity, pleiotropic cross-talk between systemic immune signaling, inflammatory cascades, and neurobiological sleep architecture provides a biological framework for investigating its link to sleep traits.
Association with Composite Sleep Health Scores
Recent large-scale genome-wide association studies (GWAS) analyzing multidimensional sleep phenotypes in biobanks such as the UK Biobank have identified rs201449027 as an independent signal linked to composite sleep health scores. Published work in Communications Biology (such as [Genome-wide association analysis of composite sleep health scores in 413,904 individuals](https://www.nature.com/articles/s42003-025-07514-0)) utilized principal component analysis to combine multiple self-reported parameters—including sleep duration, insomnia symptoms, chronotype, daytime sleepiness, and napping—into unified measures of sleep quality. The rs201449027 variant demonstrated genome-wide significant correlation with these composite indices. However, the evidence strength remains categorized as limited because these findings capture subtle statistical shifts across vast populations rather than large single-gene effects, and experimental follow-ups delineating precise causal mechanisms are ongoing.
Population Frequency and Allelic Distribution
Data from the Genome Aggregation Database (gnomAD) and dbSNP indicate that rs201449027 is a rare genetic variant across global populations. Its minor allele frequency (MAF) consistently remains below 0.01 (1%), meaning that more than 99% of people carry two copies of the common reference allele. Most association signals involving this variant have emerged from large European-ancestry cohorts due to statistical sample sizes in primary discovery sets. Consequently, the prevalence, linkage structure, and phenotypic impact of rs201449027 in non-European ancestries remain incompletely characterized, emphasizing the need for diverse multi-ancestry cohort analyses in sleep genetics.
Clinical Utility and What This Information Means for You
Having information about rs201449027 cannot diagnose a sleep disorder, predict specific nighttime disturbances, or define individual sleep requirements. Complex traits like sleep quality, duration, and rhythm are polygenic, shaped by thousands of minor genetic variants alongside lifestyle, circadian hygiene, mental health, and physical environment. This SNP is an educational research marker, not a clinical diagnostic test. Anyone experiencing persistent sleep difficulties, excessive daytime somnolence, or suspected sleep apnea should consult a physician or certified sleep medicine specialist rather than interpreting statistical association data as personal health status.
How common is this variant?
rs201449027 is classified as a rare variant, exhibiting a minor allele frequency (MAF) below 0.01 (<1%) across broad populations in gnomAD. Most individuals globally are homozygous for the common reference allele.
Frequently asked questions
Does having the rs201449027 variant mean I will suffer from insomnia?
No, carrying this variant does not mean you have or will develop insomnia. rs201449027 was identified through statistical associations with composite sleep scores in population-scale studies, and individual sleep outcomes depend primarily on polygenic background, daily habits, and environmental factors.
What is the KLRG1 gene and why is an immune gene linked to sleep?
KLRG1 encodes killer cell lectin-like receptor G1, an inhibitory marker found on natural killer cells and memory T cells. The immune and nervous systems continuously interact, and systemic inflammatory mediators often influence neural circuits that regulate circadian rhythms and sleep patterns.
Can a genetic test for rs201449027 guide medical treatment for sleep disorders?
No, this genetic marker is not used clinically to diagnose or treat sleep disorders. Clinical sleep assessments rely on medical history, sleep logs, and diagnostic studies such as polysomnography rather than non-coding exploratory SNPs.
How common is the rs201449027 variant in the general population?
It is a rare variant with a minor allele frequency under 1% in worldwide databases like gnomAD. More than 99% of people carry two copies of the common baseline allele.
Sources & further reading
Educational information only, last refreshed 9/7/2026. Not medical advice — these associations describe population statistics, not individual predictions.
Curious what your genotype is for rs201449027?
Upload a raw DNA file from 23andMe, AncestryDNA, MyHeritage, or FamilyTreeDNA and see this variant — plus thousands more — interpreted in your full report.
Get my report — $29