AQP4 rs162009: What Your Genotype Means
The rs162009 variant is a single nucleotide polymorphism located within the AQP4 gene. Research has investigated its potential association with the risk of developing REM sleep behavior disorder (RBD) symptoms in individuals already diagnosed with Parkinson's disease.
What each genotype means
Lower REM sleep disorder risk
Research indicates that individuals with this genotype may have a lower risk of developing REM sleep behavior disorder (RBD) symptoms if they are diagnosed with Parkinson's disease. Additionally, some studies suggest this genotype is associated with better cognitive performance and lower amyloid deposition in the brain, potentially reflecting the role of AQP4 in waste clearance.
The A allele is common, with frequencies reported around 56% in some studied populations.
Typical AQP4 variant profile
This genotype represents a heterozygous state for the rs162009 variant. While some studies group AG carriers with AA carriers when observing protective effects against certain Parkinson's-related symptoms, the specific clinical implications for AG individuals can be variable and less pronounced than in AA homozygotes.
This genotype is frequently observed in the general population, reflecting the common nature of both the A and G alleles.
Standard AQP4 variant profile
Individuals with this genotype do not carry the A allele associated with the potential protective effects against REM sleep behavior disorder in Parkinson's disease. Research suggests that carriers of the G allele may show different patterns of brain activity and cognitive performance compared to those with the AA genotype.
The G allele is a common variant, and the GG genotype is found at a significant frequency across diverse populations.
Understanding the rs162009 Variant
The rs162009 variant is a specific change in the DNA sequence of the AQP4 gene. In genetics, a single nucleotide polymorphism (SNP) represents a variation at a single position in the DNA chain. This particular SNP is situated in the promoter region of the M23 variant of the AQP4 gene. The promoter region is a critical segment of DNA that acts as a control switch, determining how much of a specific protein is produced by the cell. Because of its location, researchers hypothesize that rs162009 might influence the expression levels or the functional organization of the AQP4 protein within the brain, though the exact biological mechanism remains a subject of ongoing scientific investigation.
The Role of the AQP4 Gene
The AQP4 gene provides instructions for creating the Aquaporin-4 protein, which functions as a water channel in the brain. These channels are primarily found on the surface of astrocytes, a type of support cell in the central nervous system. AQP4 is a key component of the glymphatic system, a network that facilitates the flow of cerebrospinal fluid to clear metabolic waste products, such as amyloid-beta and tau proteins, from the brain. Proper glymphatic function is essential for maintaining brain health, and dysfunction in this system has been linked to various neurodegenerative conditions. By regulating water movement, AQP4 helps maintain the delicate balance of the brain's internal environment, which is vital for normal cognitive and physiological processes.
Research and Evidence Strength
Current evidence regarding rs162009 is considered limited. A 2025 study involving an Italian cohort examined this SNP alongside others to see if they correlated with Parkinson's disease (PD) risk. While the researchers found no significant link between rs162009 and the overall risk of developing PD, they observed that individuals with the AA genotype appeared to have a lower risk of developing REM sleep behavior disorder (RBD) symptoms compared to those with other genotypes. RBD is a sleep disorder often associated with the progression of Parkinson's. It is important to note that these findings are preliminary and based on specific study populations. Further research is required to confirm these associations across diverse ethnic groups and to understand the complex interactions between AQP4, sleep patterns, and neurodegenerative disease progression.
Interpreting Your Genetic Information
Genetic variants like rs162009 provide insights into biological predispositions, but they do not function as diagnostic tools. The presence of a specific genotype does not guarantee or prevent the development of any medical condition. If you are concerned about sleep disturbances, cognitive changes, or symptoms related to Parkinson's disease, it is essential to consult with a qualified healthcare professional or a neurologist. They can provide a comprehensive evaluation based on your clinical history, physical examinations, and appropriate diagnostic testing. Never use genetic information to make independent medical decisions or to alter any prescribed treatments. Always discuss your health concerns and any genetic findings with your clinician to ensure you receive personalized, evidence-based care.
How common is this variant?
The frequency of the rs162009 genotypes is variable and depends significantly on the ancestral background of the population being studied.
Frequently asked questions
Is rs162009 a diagnostic test for Parkinson's disease?
No, rs162009 is not a diagnostic test. It is a genetic variant that has been studied for its potential association with specific symptoms in patients who have already been diagnosed with Parkinson's disease.
Can I change my risk by knowing my AQP4 genotype?
Genetic variants are inherited and cannot be changed. Knowing your genotype does not provide a way to alter your biological risk, but it may be a topic to discuss with your doctor if you are managing specific neurological health concerns.
What is the glymphatic system?
The glymphatic system is a waste-clearance pathway in the brain that uses cerebrospinal fluid to remove metabolic byproducts. AQP4 is a critical protein that helps this system function effectively.
Should I take supplements if I have the AA genotype?
There is no evidence that specific supplements can mitigate risks associated with this genetic variant. Always consult with your healthcare provider before starting any new supplement regimen.
Sources & further reading
Educational information only, last refreshed 11/2/2026. Not medical advice — these associations describe population statistics, not individual predictions.
Curious what your genotype is for rs162009?
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 — $29Related variants in AQP4
This variant is linked to the presence of hallucinations in patients with Parkinson's disease, suggesting a role in glymphatic system-related sleep disturbances.
A variant in the AQP4 gene associated with differential responses to total sleep deprivation.
This AQP4 variant moderates the effect of sleep latency on brain amyloid-beta burden and has been linked to altered trajectories of cognitive decline.
This Aquaporin-4 variant is associated with poorer overall sleep quality and moderates the relationship between sleep duration and brain amyloid-beta burden.
This variant in the AQP4 gene moderates the association between sleep duration and brain amyloid-beta burden, where longer sleep duration is linked to higher amyloid levels in minor allele homozygotes.
This variant in the AQP4 gene is associated with the moderation of sleep latency effects on brain amyloid-beta and is implicated in cognitive decline trajectories.