Investigation of the association between CALCRL polymorphisms and primary angle closure glaucoma.

To determine whether the polymorphisms of calcitonin receptor-like receptor gene (CALCRL) are associated with primary angle closure glaucoma (PACG) in a southern Chinese population. A total of 207 individuals with acute and chronic PACG and 205 ethnically matched controls were recruited in the current study. A tag-single nucleotide polymorphism approach was used to investigate this gene. Alleles were determined by PCR restriction fragment length polymorphism. The results show a nominal association between rs1157699 and acute PACG (uncorrected p=0.024 and 0.028 for alleles and genotypes, respectively). Haplotype T(rs840617)C(rs6759535)T(rs1157699) frequency is significantly higher in acute PACG patients than in controls (corrected p=0.012), whereas haplotype T(rs840617)C(rs6759535)C(rs1157699) frequency is significantly lower in acute PACG patients compared with controls (corrected p=0.02). However, no significant difference was detected between chronic PACG and CALCRL tag single nucleotide polymorphisms. The study suggests a possible role of CALCRL in the pathogenesis of acute PACG but not chronic PACG. A replication of this study with a larger sample size as well as on different populations will be helpful in confirming this finding.