Common sequence variants in the LOXL1 gene in pigment dispersion syndrome and pigmentary glaucoma

BACKGROUND: Single nucleotide polymorphisms (SNPs) within the LOXL1 gene are associated with pseudoesfoliation syndrome and pseudoesfoliation glaucoma. The aim of our study is to investigate a potential involvement of LOXL1 gene in the pathogenesis of pigment dispersion syndrome (PDS) and pigmentary glaucoma (PG). METHODS: A cohort of Caucasian origin of 84 unrelated and clinically well-characterised patients with PDS/PG and 200 control subjects were included in the study. Genomic DNA from whole blood was extracted and the coding and regulatory regions of LOXL1 gene were risequenced in both patients and controls to identify unknown sequence variations. Genotype and haplotype analysis were performed with UNPHASED software. The expression levels of LOXL1 were determined on c-DNA from peripheral blood lymphocytes by quantitative real-time RT-PCR. RESULTS: A significant allele association was detected for SNP rs2304722 within the fifth intron of LOXL1 (Odds ratio (OR = 2.43, p-value = 3,05e-2). Haplotype analysis revealed the existence of risk and protective haplotypes associated with PG-PDS (OR = 3.35; p-value = 1.00e-5 and OR = 3.35; p-value = 1.00e-4, respectively). Expression analysis suggests that associated haplotypes can regulate the expression level LOXL1. CONCLUSIONS: Haplotypes of LOXL1 are associated with PG-PDS independently from rs1048661, leading to a differential expression of the transcript.