Strong association with the three LOXL1 common sequence variants was seen in both the PEX and PEXG patient groups independent of their geographic origin (rs2165241, combined OR = 3.42, P = 1.28 x 10(-40); rs1048661, OR = 2.43, P = 2.90 x 10(-19); and rs3825942, OR = 4.87, P = 8.22 x 10(-23)).
However, in 2007 a genome-wide association study in Iceland using more than 300 000 markers [single nucleotide polymorphisms (SNPs)] on a relatively small number of patients did discover that lysyl oxidase like 1 (LOXL1) on chromosome 15q24 is a major gene for XFS/XFG.
Japanese patients with POAG (n=213) or XFS (n=89) and 191 control subjects were analyzed for LOXL1 polymorphisms (rs1048661: 758G/T, Arg141Leu and rs3825942: 794G/A, rs3825942" genes_norm="4016">Gly153Asp).
A role for microfibrils in glaucoma is suggested by identification of risk alleles in LOXL1 for exfoliation glaucoma and mutations in LTBP2 for primary congenital glaucoma, both of which are microfibril-associated genes.
These findings provide biological insights into the pathology of XFS and highlight a potential role for naturally occurring rare LOXL1 variants in disease biology.
Our study reveals that in the German population the LOXL1 genetic predisposition is limited to exfoliation glaucoma and does not include normal tension glaucoma.
The results suggested that the LOXL1 variants, which are well-established markers for EX, are not likely genetic markers for CRVO in Japanese subjects.
At the very least, the discovery of the association between LOXL1 variants and XFS has opened the door to the discovery of environmental risk factors for this condition.
Our previous data suggested that three single-nucleotide polymorphisms (SNPs), rs1048661, rs3825942, and rs2165241, of the lysyl oxidase-like 1 gene (<i>LOXL1</i>) are significantly associated with exfoliation syndrome (XFS) and exfoliation glaucoma (XFG).
The frequency of G allele in R141L and G153D SNPs of the LOXL1 gene did not differ between XFS/XFG patients with and without CVD, but its frequency was different in XFS/XFG and ischemic stroke.
A probable intragenic epistasis effect was assessed by comparing the frequencies of the rs41435250 alleles among a subset of 51 patients with XFS/XFG without the high-risk TT genotype at LOXL1 intronic rs2165241 and the control group.
The AA genotype of G153D confers XFS risk in this population, as opposed to the GG genotype described in all other populations, suggesting that unidentified genetic or environmental factors independent of these LOXL1 SNPs may influence phenotypic expression of the syndrome.
These results indicate that the G153DLOXL1 variant is significantly associated with an increased risk of pseudoexfoliation and pseudoexfoliation glaucoma in an ethnically diverse patient population from the Northeastern United States.
The SNPs of LOXL1 did not exhibit any significant association with POAG or PACG, unlike previous studies from Icelandic, Swedish, U.S., and Australian populations with XFS/XFG.