Abstract
Purpose: :
To test the association between the CAST gene and keratoconus.
Methods: :
We genotyped 8 SNPs along the whole gene, including the 5’ promoter and 3’ noncoding regions, in both the family-based keratoconus samples and case-control groups. 391 family subjects (251 Caucasians, 140 were from Hispanics or other ethnic groups) in 68 keratoconus pedigrees were initial studied. In addition, 77 cases and 71 controls (all Caucasians) selected from independent samples were used as the confirmation. Transmission disequilibrium test (TDT) implemented in GeneHunter 2.0 was performed for the family samples and chi-square test was used for the case-controls samples. Both single SNP and haplotype analysis were conducted.
Results: :
Among 8 SNPs tested along the CAST gene, one SNP had no polymorphism. Using family samples, we observed a nominal significance at two markers (rs4869307: transmitted vs non-transmitted: 27 vs 17, p=0.016; rs27654: transmitted vs non-transmitted: 42 vs 26, p=0.052) for all pedigrees. Using the haplotype approach, the most significant association was obtained in haplotype GAC (rs4869307, rs151904 and rs10515244) for Caucasians (p=0.002) and haplotype ACG (rs151904, rs10515244, and rs27654) for all pedigrees (p=0.002). However, there were no significant associations identified in the case-control samples for both single SNP analysis and the haplotype approach.
Conclusions: :
These results suggest that the CAST gene may contribute to the etiology of keratoconus. A small sample size of case-control design did not confirm the associations identified in the family panel. Further studies with larger samples will be needed to confirm these findings.