PAX8 rs1823125: What Your Genotype Means for Sleep Duration
The genetic variant rs1823125 is a single nucleotide polymorphism located near the PAX8 gene on chromosome 2. Research has identified this variant as being associated with small, incremental differences in habitual sleep duration.
What each genotype means
Typical baseline sleep duration
You carry two copies of the common C allele at rs1823125 near the PAX8 locus. In population-level genome-wide association studies, this genotype represents the reference baseline and is not associated with an increase in typical self-reported sleep length. Sleep duration is a complex trait influenced by many lifestyle, health, and environmental factors alongside small genetic contributions.
Carried by approximately 50% to 55% of individuals of European ancestry and roughly 77% of individuals of African ancestry.
Slightly longer habitual sleep
You carry one copy of the T allele near the PAX8 gene. Genome-wide association studies have statistically linked each copy of the minor T allele to approximately 3 minutes longer habitual sleep per night. This is an extremely modest statistical effect on a complex trait and does not diagnose any sleep condition.
Carried by approximately 38% to 40% of individuals of European ancestry and about 21% of individuals of African ancestry.
Slightly longer habitual sleep
You carry two copies of the T allele near the PAX8 gene. In published research, having two copies of this variant is statistically associated with roughly 6 minutes longer habitual sleep per night compared to the common CC genotype. Because overall sleep duration is predominantly governed by sleep hygiene, environment, and multiple polygenic factors, the physiological effect of this single variant remains very small.
Carried by approximately 6% to 7% of individuals of European ancestry and around 1% to 2% of individuals of African ancestry.
Understanding the rs1823125 Variant
The variant rs1823125 is a single nucleotide polymorphism, or SNP, which is a common type of genetic variation where a single building block of DNA—a nucleotide—differs between individuals. This specific SNP is located in an intergenic region, meaning it sits in the DNA sequence between genes rather than within a gene that codes for a protein. Specifically, it is positioned approximately 35 to 80 kilobases upstream of the PAX8 gene. In genetics, variants in these non-coding regions are often studied for their potential role in regulating how nearby genes are turned on or off. While rs1823125 does not change the structure of a protein directly, its location near a significant transcription factor has made it a subject of interest in large-scale genome-wide association studies (GWAS) aimed at understanding the biological underpinnings of complex human traits like sleep patterns.
The Role of the PAX8 Gene
The PAX8 gene provides instructions for making a protein that acts as a transcription factor. Transcription factors are specialized proteins that bind to specific regions of DNA to help control the activity of other genes. PAX8 is particularly well-known for its essential role in the development and proper function of the thyroid gland. It is also involved in the development of the kidneys and certain parts of the central nervous system. Because PAX8 is critical for thyroid function, and thyroid hormones are known to influence metabolism and energy levels, researchers have investigated whether variations near this gene might indirectly influence physiological processes that affect sleep. While the exact mechanism linking the intergenic region near PAX8 to sleep duration remains an active area of scientific inquiry, the gene's broad influence on development and hormonal regulation provides a plausible biological context for why variants in this neighborhood might be associated with sleep-related traits.
Research and Evidence Strength
The association between rs1823125 and sleep duration was first highlighted in large-scale genome-wide association studies, most notably by the CHARGE Consortium. In these studies, researchers analyzed the genomes of tens of thousands of individuals to find correlations between specific genetic markers and self-reported sleep habits. The findings indicated that each copy of the minor allele at rs1823125 is associated with a modest increase in sleep duration, estimated at approximately 3.1 minutes per night. It is important to note that while this association reached genome-wide significance in large cohorts, the effect size is very small. Furthermore, the evidence is considered limited in terms of clinical utility; these findings describe population-level statistical trends rather than individual diagnostic markers. The association has been replicated in different cohorts, including African-American samples, though the strength and frequency of the signal can vary across different ancestral backgrounds.
Interpreting Your Results
When reviewing information about rs1823125, it is essential to understand that this variant is associated with a very minor shift in sleep duration at a population level. It is not a 'sleep gene' that determines whether you are a long or short sleeper, nor is it a diagnostic tool for sleep disorders. Many factors, including environment, lifestyle, stress, and hundreds of other genetic variants, play a much larger role in determining your actual sleep habits. Because the effect size is so small, knowing your genotype for this SNP does not provide actionable medical information. If you are concerned about your sleep quality, duration, or patterns, you should consult with a healthcare professional or a sleep specialist. They can provide personalized guidance based on your health history and clinical symptoms, which are far more informative than any single genetic variant.
How common is this variant?
The minor allele frequency for rs1823125 is approximately 0.26 in European discovery samples and has been observed at a frequency of 0.12 in replication samples.
Frequently asked questions
Does rs1823125 determine how much sleep I need?
No, this variant is only associated with a very small, statistically significant difference in sleep duration at the population level. It does not determine your individual sleep needs, which are influenced by a complex combination of genetics, lifestyle, and environment.
Can I use this information to diagnose a sleep disorder?
No, this variant is not a diagnostic tool for any sleep disorder. If you are experiencing sleep problems, you should speak with a doctor or a sleep specialist to discuss your symptoms and health history.
Why is the effect of this SNP so small?
Most complex human traits, including sleep duration, are polygenic, meaning they are influenced by many different genetic variants, each contributing a tiny amount to the overall trait. Additionally, non-genetic factors like daily routine and stress often have a much larger impact on sleep than any single SNP.
Is this variant related to thyroid health?
The variant is located near the PAX8 gene, which is important for thyroid development. However, the association found in studies is specifically with sleep duration, and there is no evidence that this specific SNP is a marker for thyroid disease.
Sources & further reading
Educational information only, last refreshed 10/17/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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This variant is a well-replicated genome-wide significant locus associated with habitual sleep duration, including both short and long sleep phenotypes.
This intergenic variant near the PAX8 gene is a well-replicated genetic marker associated with variations in habitual sleep duration.
An intergenic variant near PAX8 identified in large-scale GWAS meta-analyses as a locus influencing habitual sleep duration, with evidence suggesting potential regulatory effects on nearby transcripts.
This intergenic variant near the PAX8 gene is associated with small, incremental changes in habitual sleep duration.
A variant near the PAX8 locus associated with self-reported sleep duration in large population-based cohorts.
Genome-wide significant locus associated with average adult self-reported and accelerometer-measured sleep duration.