The leading cause of blindness worldwide, though surgery reliably fixes it where it is available. A locus near CRYAA — a gene the eye's lens is physically built from — showed its activity actually falling in human lens tissue as cataract severity rises.
A cataract is clouding of the eye's lens, and age-related cataract is the leading cause of blindness worldwide — not because it cannot be fixed, but because access to the surgery that reliably fixes it remains limited in many lower-income countries. Nuclear cataract, the subtype this page covers, clouds the centre of the lens — the part responsible for most of its focusing power.
The study behind this page combined genome-wide association studies in 4,569 Asian participants — Malay and Indian — and replicated the results in a further 2,481 Chinese participants from two independent cohorts, for a combined total of 7,140. It confirmed two loci at genome-wide significance. The first sits near KCNAB1; the second, held on this page, is rs11911275, near CRYAA — a gene that encodes one of the major crystallin proteins the eye's lens is physically built from.
The study did not stop at the statistical association. Researchers measured how active both genes were in actual human lens tissue, across a range of cataract severity, and found that CRYAA activity went down as nuclear cataract severity went up (KCNAB1 moved the opposite way, up with severity). A structural protein of the lens becoming less active as the lens clouds is a finding that connects a statistical signal directly to the tissue doing the clouding — a mechanism read off the organ itself, not only inferred from genetics.
Cataracts are diagnosed by an eye examination, and the only effective treatment is surgery to remove the clouded lens and replace it with an artificial one — a routine procedure with a very high success rate where it is available. Nothing about the decision to operate, or its outcome, depends on a genotype.
What this page cannot do. This variant shifts risk by a fraction and does not predict who will develop cataracts or when. Blurred vision, glare sensitivity, or difficulty seeing at night that develops gradually with age is what actually leads to an eye examination and, if needed, surgery — nothing here should delay that.
Because surgery is highly effective, the disability caused by cataract worldwide is overwhelmingly a story about who can reach that surgery, not about who is genetically predisposed. This page's finding is a genuine piece of the biology of how the lens clouds with age; it does not change the practical fact that the most effective intervention against cataract blindness globally is expanding access to the operation that already exists.
What a 23andMe/AncestryDNA export or raw VCF can and can't tell you about Age-Related Nuclear Cataracts comes down to these specific, well-studied positions — not a diagnosis.
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Age-Related Nuclear Cataracts. MyGeneLog™. https://www.mygenelog.com/conditions/age-related-nuclear-cataracts
No. This variant shifts risk by a fraction and does not predict an individual outcome. Gradually blurred vision, glare, or trouble seeing at night with age is what leads to an eye examination, which is how cataracts are actually found.
The researchers measured the gene's own activity directly in human lens tissue across a range of cataract severity and found it dropping as the cataract worsened — evidence read from the tissue itself doing the clouding, not only inferred from a genetic association.
Because surgery reliably removes the clouded lens regardless of why it clouded, and is highly effective. Worldwide, what actually determines cataract-related blindness is overwhelmingly access to that surgery, not genetic risk.
No. Those are typically caused by rare, high-penetrance mutations — sometimes in CRYAA itself — present from birth. This page is about common variants and the age-related form of the disease, a different condition with a different genetic basis.
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