The LOXL1 gene variations are not associated with primary open-angle and primary angle-closure glaucomas.
OBJECTIVE
Glaucoma is a complex disease involving multiple genetic factors. Recently, single nucleotide polymorphisms (SNPs) in the LOXL1 gene have been implicated in exfoliation syndrome (XFS) and exfoliation glaucoma (XFG) but not in the primary glaucomas. This study was conducted to determine the possible involvement of these SNPs in cases of primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG).


METHODS
The three associated SNPs of LOXL1 (rs1048661, rs3825942, and rs2165241) were screened in 208 unrelated and clinically well-characterized glaucoma cases comprising patients with POAG (n = 112) or PACG (n = 96) along with 105 ethnically matched normal control subjects from Indian populations. Subjects with exfoliative material on the lens and radial pigmentation in the periphery of the lens that could be earlier signs of XFS were excluded. These SNPs were screened by resequencing and further confirmed by PCR-based restriction digestions. Haplotypes were generated with the three SNPs in cases and control subjects, and linkage disequilibrium (LD) and haplotype analysis were performed with the Haploview software, which uses the EM (expectation-maximization) algorithm.


RESULTS
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. Haplotypes generated with these intragenic SNPs did not indicate any significant risk with POAG or PACG phenotypes. The risk haplotype G-G in XFS/XFG in other populations was present in 46% of the normal control subjects in the present cohort.


CONCLUSIONS
The results from the present study do not indicate the involvement of the LOXL1 SNPs in POAG and PACG.
Chakrabarti
Subhabrata
S
Kallam Anji Reddy Molecular Genetics Laboratory, LV Prasad Eye Institute, Hyderabad, India. subho@lvpei.org
Rao
Kollu Nageswara
KN
Kaur
Inderjeet
I
Parikh
Rajul S
RS
Mandal
Anil K
AK
Chandrasekhar
Garudadri
G
Thomas
Ravi
R
D000328:Adult; D000594:Amino Acid Oxidoreductases / Q000235:genetics*; D017931:DNA Primers / Q000737:chemistry; D015812:Glaucoma, Angle-Closure / Q000208:ethnology / Q000235:genetics*; D005902:Glaucoma, Open-Angle / Q000208:ethnology / Q000235:genetics*; D006239:Haplotypes; D006801:Humans; D007194:India / Q000453:epidemiology; D015810:Linkage Disequilibrium; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide
D017931:DNA Primers; D000594:Amino Acid Oxidoreductases; C445313:LOXL1 protein, human