Glaucoma is a group of eye diseases that silently damage the optic nerve. A variant near SRBD1 has been linked to normal-tension glaucoma in Japanese cohorts, but evidence outside that population is thin.
Glaucoma is not one single disease but a group of eye conditions that damage the optic nerve — the bundle of more than a million nerve fibers that carries visual information from the eye to the brain. Left untreated, that damage causes progressively worsening, permanent vision loss, usually starting at the edges of a person's visual field and, if it continues, closing in toward the center. Glaucoma is a leading cause of irreversible blindness worldwide, and it affects several million people in the United States alone, a number expected to rise substantially as the population ages.
Glaucoma has earned that nickname for a genuinely alarming reason: in its most common forms, it typically causes no pain and no noticeable symptoms until a significant amount of vision has already been lost. Peripheral vision fades so gradually, and the brain is so good at filling in the gaps using information from both eyes, that many people don't notice a problem until 40% or more of the relevant nerve fibers have already been damaged. As a result, a substantial share of people living with glaucoma don't yet know they have it — which is precisely why regular comprehensive, dilated eye exams (not just a vision-chart check) matter, especially for people with risk factors such as older age, a family history of glaucoma, or Black, Hispanic/Latino, or East Asian ancestry (each associated with elevated risk for different glaucoma subtypes).
Unlike some genetic conditions where a variant is simply informative, glaucoma is one of the clearer cases in medicine where early detection changes the outcome. Vision already lost to glaucoma cannot be restored — but with a comprehensive dilated eye exam, optic nerve imaging, and visual field testing, glaucoma can usually be caught well before a person notices any symptoms, and its progression can typically be slowed or halted with prescription eye drops, laser treatment, or surgery to lower eye pressure or otherwise protect the optic nerve. That combination — a disease that causes irreversible damage if ignored, but is genuinely manageable if caught — is exactly why eye care organizations emphasize routine screening, particularly for people with a family history or other risk factors.
A specific DNA marker, rs3213787, near a gene called SRBD1, was identified in a 2010 genome-wide genetic study of normal-tension glaucoma conducted by Japanese researchers, where it was associated with a meaningfully higher chance of NTG in that Japanese cohort. As discussed in the clinical detail section below, this finding has held up less consistently when tested in other populations — an important, honest caveat that doesn't diminish the value of understanding one's own genetic background, but does mean this particular marker should be read as a population-level research finding from a specific ancestry group rather than a universal or individually predictive test.
Locus and variant. rs3213787 is an intronic single-nucleotide variant within SRBD1 (S1 RNA-binding domain 1) at chromosome 2p21.
Discovery study and population. The variant was identified by the Normal Tension Glaucoma Genetic Study Group of the Japan Glaucoma Society (Meguro A, et al., Ophthalmology 2010; PMID 20363506; GWAS Catalog accession GCST000645) in a genome-wide association study of 305 Japanese NTG cases versus 355 Japanese controls (East Asian ancestry, Japan). rs3213787 was among the two most strongly associated SNPs in that GWAS, with p = 2.5×10⁻⁹ and an odds ratio of 2.8 (95% CI 1.96–3.99) per copy of the associated allele; per GWAS Catalog, the associated allele frequency was approximately 0.81 in that dataset. The same study also implicated a second gene, ELOVL5. Because SRBD1 and ELOVL5 have been reported to participate in cell growth and apoptosis regulation, the authors proposed these pathways could plausibly relate to NTG pathophysiology independent of intraocular pressure, though the precise causal mechanism remains uncharacterized.
Replication is inconsistent outside Japanese cohorts. A subsequent case-control study in a Korean population (Jung SH, et al., Medicine (Baltimore) 2020; PMID 32569157; 159 NTG cases, 103 controls) found no statistically significant association for rs3213787 (allelic OR 0.634, p=0.063; dominant OR 0.589, p=0.066; recessive OR 0.639, p=0.7716), with a notably lower minor allele frequency in that cohort (0.13 in cases, 0.19 in controls) than reported in the original Japanese sample. A 2024 systematic review and meta-analysis pooling multiple published case-control studies of NTG gene polymorphisms (Pan L, Wu J, Wang N, Genes 2024; PMID 38674425) nonetheless still classified rs3213787 among 16 SNPs (across 10 genes) with a statistically significant pooled association with NTG risk, indicating that, in aggregate across the available published studies (most of which are East Asian), the association persists at the meta-analytic level even though at least one individual replication attempt (the Korean cohort) did not reach significance on its own.
Bottom line on evidence strength. The rs3213787–NTG association is best characterized as a real, statistically strong finding from its founding Japanese GWAS, with support from pooled meta-analysis, but with population-specific variability in replication (non-significant in the one published Korean cohort) and no large-scale replication reported in European-ancestry or other non-East-Asian populations identified in the literature reviewed here. This should be communicated as ancestry-specific, moderately-supported research evidence rather than a broadly validated, cross-population risk marker.
Clinical context: NTG versus other glaucomas. NTG is classified as a subtype of primary open-angle glaucoma in which glaucomatous optic neuropathy (characteristic optic disc cupping, retinal nerve fiber layer thinning, and corresponding visual field loss) occurs despite intraocular pressure remaining within the statistically normal range (commonly cited as ≤21 mmHg on diurnal testing). NTG is associated with a relatively higher rate of optic disc hemorrhages and with visual field defects closer to fixation compared with high-tension POAG; proposed contributing mechanisms include vascular dysregulation (e.g., nocturnal hypotension, migraine, Raynaud phenomenon) and structural susceptibility of the lamina cribrosa, in addition to genetic susceptibility factors such as those studied here. Management follows the same general principles as other open-angle glaucomas — further lowering intraocular pressure (via topical medication, laser trabeculoplasty, or incisional surgery) remains the only evidence-based intervention shown to slow progression, even when starting pressure is within the normal range.
Diagnostic evaluation (general, not variant-specific). Standard evaluation includes tonometry (IOP measurement), gonioscopy (angle assessment), dilated optic nerve examination, optical coherence tomography of the retinal nerve fiber layer and optic nerve head, and standardized automated visual field testing; diagnosis is clinical and based on these structural and functional findings rather than on genetic testing, which has no established role in individual diagnosis or management for this gene.
What a 23andMe/AncestryDNA export or raw VCF can and can't tell you about Glaucoma comes down to these specific, well-studied positions — not a diagnosis.
Because the most common forms typically cause no pain and no noticeable symptoms until a large share of vision is already permanently lost — often 40% or more of the relevant optic nerve fibers. Regular comprehensive dilated eye exams are the main way to catch it before symptoms appear.
Yes. Normal-tension glaucoma causes the same kind of optic nerve damage and vision loss as other forms of glaucoma, but with eye pressure that measures within the typical range. It's thought to involve blood flow to the optic nerve or a nerve that's more vulnerable to damage even at ordinary pressure.
No. It's a research-identified marker that raised the odds of normal-tension glaucoma in the Japanese population where it was discovered, but a follow-up study in a Korean population did not confirm a significant association, and it hasn't been well studied in people of European or other ancestries. It should be read as suggestive, population-specific research evidence, not an individual prediction.
Once optic nerve damage has occurred, it cannot be reversed — but if glaucoma is caught early, lowering eye pressure through eye drops, laser treatment, or surgery has been shown to slow or halt further progression in most people, which is why early detection is genuinely protective of remaining vision.
General eye-health guidance recommends more frequent comprehensive dilated eye exams for people over 60, Black individuals over 40, and anyone with a family history of glaucoma or other risk factors; a clinician can advise on the right interval for a given person's risk profile.
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