CSNK1D rs2305767: What Your Genotype Means
The rs2305767 variant is a single nucleotide polymorphism located within the CSNK1D gene. It is associated with the regulation of circadian rhythms, potentially influencing individual differences in daytime alertness and sleep-wake cycle timing.
What each genotype means
Typical circadian timing
You carry two copies of the common C allele for this synonymous variant in the CSNK1D gene. Individuals with this genotype typically exhibit standard baseline patterns in sleep-wake phase regulation and daytime alertness. Because research investigating this synonymous marker's direct functional impact is limited, having this genotype suggests average population trends rather than a distinct alteration in circadian rhythm.
Carried by approximately 65% to 70% of people of European descent and around 60% of individuals of African ancestry.
Slightly shifted alertness tendency
You carry one copy of the less common T allele alongside one C allele in the CSNK1D circadian clock gene. In preliminary observational studies, heterozygous carriers show modest statistical variations in daytime alertness and slight shifts in familial sleep-wake timing compared to the reference group. However, scientific evidence linking this synonymous marker to definite circadian outcomes remains limited and non-diagnostic.
Found in roughly 25% to 30% of individuals of European ancestry and about 30% to 35% of individuals of African ancestry.
Altered circadian phase tendency
You carry two copies of the less common T allele at this synonymous site in CSNK1D. Some early research associates this genotype with modest differences in familial sleep-wake phase regulation and subjective morning or daytime alertness levels. Current published evidence is limited and correlational, meaning this genotype does not cause or diagnose a circadian sleep disorder.
Carried by approximately 3% to 4% of individuals in European cohorts and roughly 4% to 5% of individuals of African ancestry.
Understanding the rs2305767 Variant
The rs2305767 variant is a specific genetic change, or single nucleotide polymorphism (SNP), found within the CSNK1D gene. In genetics, a SNP represents a variation at a single position in the DNA sequence among individuals. This particular variant is classified as an exonic synonymous variant, meaning that while it occurs within the coding region of the gene, it does not change the amino acid sequence of the resulting protein. Despite this, synonymous variants can sometimes influence gene expression, mRNA stability, or the efficiency of protein translation. Researchers study these variants to understand how subtle differences in our genetic code contribute to the diversity of human traits, such as how our internal biological clocks function and how we respond to environmental light and dark cycles.
The Role of the CSNK1D Gene
The CSNK1D gene provides instructions for making an enzyme called casein kinase 1 delta. This enzyme plays a critical role in the regulation of circadian rhythms, which are the physical, mental, and behavioral changes that follow a 24-hour cycle. Casein kinase 1 delta acts as a molecular timer by phosphorylating various proteins involved in the circadian clock mechanism, effectively controlling the speed and stability of these internal rhythms. Because this enzyme is essential for maintaining the timing of sleep and wakefulness, variations in the CSNK1D gene have been a subject of interest in sleep research. While some rare mutations in this gene are linked to specific sleep disorders, common variants like rs2305767 are investigated for their potential to influence the natural variation in sleep-wake timing observed across the general population.
Research and Evidence Strength
Current research into rs2305767 suggests a link to circadian regulation, specifically regarding daytime alertness and the timing of the sleep-wake cycle. However, the evidence strength for this association is currently considered limited. While some studies have explored the role of CSNK1D in sleep patterns, the functional impact of this specific synonymous variant remains a topic of ongoing investigation. It is important to note that complex traits like sleep timing are polygenic, meaning they are influenced by many different genes, environmental factors, and lifestyle choices. Because the evidence is limited, it is not possible to use this variant to predict an individual's sleep behavior or diagnose a sleep disorder. The scientific community continues to gather data to better understand how this and other variants contribute to the complex architecture of human circadian biology.
Population Frequency
The frequency of the rs2305767 variant varies across different ancestral groups. Data indicates a minor allele frequency (MAF) of approximately 0.18 in European populations and approximately 0.22 in African ancestry cohorts. These frequencies suggest that the variant is relatively common, appearing in a significant portion of the population. Understanding these frequencies is essential for researchers as they conduct genome-wide association studies to determine if specific genetic markers are linked to particular traits. Because the variant is common, it is likely that many individuals carry one or two copies of the minor allele, highlighting the natural genetic variation that exists within human populations regarding circadian-related traits.
Interpreting Your Genetic Information
If you have access to your genetic data regarding rs2305767, it is important to view this information in the context of current scientific understanding. This variant is not a diagnostic tool and cannot determine your sleep quality or circadian type. Genetic associations are statistical observations made across large groups of people and do not necessarily apply to any single individual. If you have concerns about your sleep patterns, daytime alertness, or potential sleep disorders, the most appropriate course of action is to consult with a healthcare professional or a sleep specialist. They can provide a comprehensive evaluation based on your clinical history and symptoms. Never use genetic information to make decisions about your health or to alter your lifestyle without professional medical guidance.
How common is this variant?
The variant has a minor allele frequency of approximately 0.18 in European populations and 0.22 in African ancestry cohorts.
Frequently asked questions
Can rs2305767 predict if I am a morning person or a night owl?
No, this variant cannot predict your chronotype. While it is associated with circadian regulation, sleep timing is a complex trait influenced by many genes and environmental factors.
Is rs2305767 linked to any sleep disorders?
While some rare mutations in the CSNK1D gene are linked to familial advanced sleep phase syndrome, rs2305767 is a common variant with only limited evidence suggesting a role in general sleep-wake cycle regulation.
Should I change my sleep habits based on my rs2305767 genotype?
No, you should not change your habits based on this genetic information. If you are experiencing sleep issues, please consult a healthcare provider for personalized medical advice.
What does it mean that rs2305767 is a synonymous variant?
A synonymous variant means the change in the DNA sequence does not alter the amino acid sequence of the protein produced by the gene. It is often referred to as a silent mutation, though it may still have subtle effects on gene regulation.
Sources & further reading
Educational information only, last refreshed 10/19/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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This missense mutation (Thr44Ala) in the CSNK1D gene is a known cause of familial advanced sleep phase syndrome (FASPS).
The T44A missense mutation in CSNK1D accelerates circadian period length and is linked to familial advanced sleep phase syndrome and migraine.
A rare missense variant (p.His205Arg) in CSNK1D causing familial advanced sleep phase syndrome type 2.
Missense variant (Thr44Ala) in CSNK1D; pathogenic for Familial Advanced Sleep Phase Syndrome 2 (FASPS2).
This variant in CSNK1D is linked to familial advanced sleep phase syndrome, influencing circadian period length.
This variant is linked to advanced sleep phase syndrome, affecting the regulation of the circadian clock.