rs3825942

rs3825942, also known as G153D, a SNP causing an amino acid change in the lysyl oxidase 1 LOXL1 gene, has been linked to exfoliation glaucoma (also known as exfoliation syndrome). This form of glaucoma causes up to 10% of the cases of blindness in many countries, including the US. From the abstract of this study: "Approximately 25% of the general population is homozygous for the highest risk haplotype [C;C here combined with other risk SNPs] and their risk of suffering XFG (exfoliation glaucoma) is over 100 times that of those only carrying low-risk haplotypes." The risk allele for this SNP is rs3825942(C), as oriented with respect to the dbSNP entry, and it confers a estimated relative risk (by itself) of 27 compared to the (T) allele. The odds ratio is 20.10 (CI 10.80-37.41). [Note that the (C) allele is actually quite common in most European populations.] A meta-analysis including 24 articles across 5 ethnicities (Caucasian, African, Japanese, Indian, and Chinese) concluded that rs3825942 is the common disease-associated SNP in all populations, whereas rs1048661 and rs2165241 were inconsistent. The odds ratio is approximately 10 for rs3825942(C;C), while the heterozygote rs3825942(C;T) was not statistically significant. rs3825942 was not associated with primary open angle glaucoma (POAG). With so many people at high risk, shouldn't the number of cases be much higher? Not necessarily, since glaucoma risk only becomes high in older individuals. [To put it another way: plenty of folks don't live long enough to find out if they would have gotten glaucoma.] The estimate for glaucoma incidence worldwide is 10-20% only for individuals over 60 years of age; in Iceland, where glaucoma incidence is high, 40% of individuals 80 or older show signs of exfoliation syndrome, which has been seen to convert to exfolation glaucoma at a rate of 60% - over a 15 year period. PMID 12928689, PMID 10463402, PMID 17224761 discussed in this blog post rs1048661 (G), rs3825942 (C), and rs2165241 (T) are highly associated with XFS and XFG in American and European populations. The GGT haplotype constitutes a major risk haplotype for exfoliation. Confirmed as risk for pseudoexfoliation (PEX) and pseudoexfoliation glaucoma (PEXG) in populations of German and Italian descent. Although not conducted with a large number of patients, in a study of black South Africans the rs3825942(T) allele was the risk allele, in contrast to other populations. {PMID Auto |PMID=22065931 |Title=Decreased total antioxidants status in the plasma of patients with pseudoexfoliation glaucoma. }}

A;A

Unless you are a black south African, this uncommon SNP drastically reduces your risk of exfoliation glaucoma (also known as exfoliation syndrome, or pseudoexfoliation syndrome PEX). That form of glaucoma causes up to 10% of the cases of blindness in many countries, including the US. This mutation may not protect you from other kinds of glaucoma though.

A;G

Unless you are a black South African, probably lower than average risk of exfoliation glaucoma (PEX).

G;G

This genotype is found in 2 out of 3 people, but has been repeatedly linked to a much higher risk of glaucoma. However a 2010 paper in a south african population reports reduced risk, casting some doubts.