STK39 rs807037: Keratoconus Risk and Vision Genetics
The rs807037 variant is a single nucleotide polymorphism located within the STK39 gene on chromosome 2. Genome-wide association research has identified it as a lead susceptibility marker linked to a modestly increased risk of developing keratoconus in populations of European ancestry. As a common risk allele rather than a direct causative mutation, it reflects one piece of a complex, multifactorial ocular trait.
What each genotype means
Typical keratoconus risk
You carry two copies of the baseline A allele at rs807037 in the STK39 locus. In genome-wide association studies, this genotype has not been associated with the elevated risk of keratoconus seen with the alternative G allele. Because keratoconus is a complex trait influenced by multiple genetic loci and environmental factors such as eye rubbing, your overall corneal health depends on many factors.
Carried by approximately 34% of individuals of European ancestry, and at varying frequencies across other global populations.
Slightly increased keratoconus risk
You carry one copy of the susceptibility G allele at rs807037 in the STK39 locus. Published association studies in European cohorts indicate that carrying this allele is statistically linked to a modest increase in the relative risk of developing keratoconus. This does not mean you will develop the condition, but it contributes to your overall polygenic susceptibility profile.
Carried by approximately 48% of individuals of European ancestry.
Moderately increased keratoconus risk
You carry two copies of the susceptibility G allele at rs807037 near the STK39 gene. Research in European populations has linked this genotype to an increased susceptibility to keratoconus compared to carrying the baseline allele. Keratoconus is multifactorial, meaning this genetic marker confers only a statistical susceptibility rather than a deterministic outcome.
Carried by approximately 18% of individuals of European ancestry.
Genetic Location and Variant Identity
The single nucleotide polymorphism cataloged as rs807037 is a genomic variant situated on chromosome 2 within the STK39 gene locus. At this specific nucleotide position, individuals typically inherit either a cytosine (C) or a thymine (T) allele. Rather than causing an overt structural disruption or coding mutation in the protein itself, rs807037 resides within non-coding sequence, acting primarily as a tag or regulatory marker. In genetic research, such variations often mark regions that modulate the expression, splicing, or regulation of adjacent genomic elements. Public databases such as dbSNP, Ensembl, and the GWAS Catalog index rs807037 to systematically map human genetic diversity and investigate how non-coding architecture influences complex human diseases.
Biological Role of the STK39 Gene
The STK39 gene encodes a serine/threonine kinase known as SPAK (SPS1-related proline/alanine-rich kinase). Historically, STK39 is best recognized for its critical physiological role in regulating ion transport across cellular membranes, particularly via the phosphorylation of cation-chloride cotransporters. While its function in renal salt handling and blood pressure regulation is well-documented in scientific literature, STK39 is also expressed in diverse ocular tissues, including the cornea. Cellular homeostasis, cellular volume, and stress-response pathways in ocular fibroblasts and epithelial cells depend heavily on precise ion regulation. Researchers hypothesize that altered STK39 activity or expression may influence corneal cell signaling, extracellular matrix remodeling, and biomechanical stability, though the exact physiological pathway leading to structural weakness remains an active area of investigation.
Association with Keratoconus
Keratoconus is a complex eye condition characterized by progressive thinning, weakening, and conical steepening of the clear central cornea, resulting in visual distortion and astigmatism. In large-scale genome-wide association studies (GWAS) involving European cohorts, rs807037 emerged as a statistically significant lead susceptibility locus for keratoconus. However, the evidence supporting this relationship is characterized as moderate. Having the risk allele does not mean an individual will develop the condition; instead, it incrementally alters baseline statistical vulnerability. Keratoconus is multifactorial, arising from a combination of polygenic risk factors and external triggers, notably chronic, vigorous eye rubbing and allergic ocular surface conditions. Importantly, the strength of association may vary considerably across different ancestral backgrounds.
Navigating Personal Genetic Data
Discovering an elevated risk genotype at rs807037 should never be construed as a clinical diagnosis of keratoconus or an inevitable sign of future vision loss. Conversely, carrying the standard or protective genotype does not provide immunity against corneal ectasia. Polygenic susceptibility loci exert subtle individual effects that must be interpreted in context with clinical evaluations. Individuals who experience symptoms such as worsening astigmatism, progressive blurring, or frequent prescription shifts should undergo specialized corneal topography or tomography performed by an optometrist or ophthalmologist. Routine eye care and avoiding mechanical trauma—such as vigorous rubbing of the eyes—remain the standard health practices for preserving corneal structural integrity, regardless of genetic predisposition.
How common is this variant?
The minor allele frequency for rs807037 is approximately 0.42 in populations of European ancestry according to large genomic reference datasets. Consequently, heterozygous (CT) and homozygous risk (TT) genotypes are widely distributed across European populations, while allele frequencies can vary significantly in other global ancestral groups.
Frequently asked questions
Does having the rs807037 risk genotype mean I will get keratoconus?
No, carrying the risk allele at rs807037 does not mean you will develop keratoconus. Keratoconus is a complex, multifactorial disorder influenced by many different genes alongside environmental triggers such as habitual eye rubbing. The variant only confers a minor statistical increase in susceptibility.
What is the STK39 gene and how does it relate to vision?
The STK39 gene provides instructions for producing an enzyme that regulates cellular ion transport and osmotic stress responses. Although STK39 is commonly studied in kidney physiology and blood pressure, its expression in ocular tissues suggests it plays a role in cellular maintenance and biomechanical integrity within the cornea.
Can genetic testing for rs807037 diagnose an eye disorder?
No, commercial or direct-to-consumer genetic testing for rs807037 cannot diagnose any medical or ocular condition. Keratoconus is diagnosed exclusively through clinical examinations, including corneal topography and pachymetry conducted by an eye care specialist.
What actionable steps can I take if I have the risk allele?
The most effective step you can take is to practice good eye hygiene by strictly avoiding vigorous eye rubbing, which is a known mechanical risk factor for corneal weakening. Additionally, schedule regular comprehensive eye exams if you experience changes in your vision or astigmatism.
Sources & further reading
Educational information only, last refreshed 9/11/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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