Abstract
Purpose: :
Single nucleotide polymorphisms (SNPs) in the LOXL1 gene have been implicated as the principal genetic risk factor for exfoliation syndrome (XFS). XFS is associated with sensorineural hearing loss (SNHL). We investigated whether LOXL1 genetic variations also confer risk factor for age-related SNHL.
Methods: :
We recruited 99 SNHL patients (54M, mean age 72.8 +/- 10.9; 45F, mean age 72.0 +/- 10.3), defined as hearing thresholds on pure-tone audiometry >25dB at any of the examined frequencies in one or both ears. LOXL1 gene polymorphisms (R141L and G153D) were genotyped in 276 subjects (84 cases and 192 controls) by direct sequencing. Association studies were carried out with SNP-STAT and PLINK programs.
Results: :
Case-control genotypic comparisons were not significant for R141L (p=0.080) and G153D (p=0.060). The corresponding allelic frequencies for cases and controls were 0.679 and 0.738 for R141L/G-allele (p=0.153; OR=1.34) and 0.857 and 0.780 for G153D/G-allele (p=0.036; OR=0.591), respectively. As the observed G153D/G-allele frequency was overrepresented in the cases, we further examined the combined haplotype effect of both R141L and G153D in these subjects. Marginally significant association was observed for underrepresented "GA" haplotype in cases (p=0.041; OR=0.60). Relative haplotype comparisons was only significant when underrepresented "GA" haplotype was compared with overrepresented "TG" haplotype (p=0.027; OR=1.88). In view of this observation, we are genotyping additional cases and further sequencing the entire LOXL1 coding exons in a group of SNHL subjects.
Conclusions: :
The association of LOXL1 gene polymorphisms with XFS may also be true for SNHL. Our marginally observed association between LOXL1 and SNHL requires further confirmation.