@article {1340, title = {Association of polymorphisms in the hepatocyte growth factor gene promoter with keratoconus.}, journal = {Invest Ophthalmol Vis Sci}, volume = {52}, year = {2011}, month = {2011 Oct 31}, pages = {8514-9}, abstract = {

PURPOSE: Keratoconus is a progressive disorder of the cornea that can lead to severe visual impairment or blindness. Although several genomic regions have been linked to rare familial forms of keratoconus, no genes have yet been definitively identified for common forms of the disease.

METHODS: Two genome-wide association scans were undertaken in parallel. The first used pooled DNA from an Australian cohort, followed by typing of top-ranked single-nucleotide polymorphisms (SNPs) in individual DNA samples. The second was conducted in individually genotyped patients, and controls from the USA. Tag SNPs around the hepatocyte growth factor (HGF) gene were typed in three additional replication cohorts. Serum levels of HGF protein in normal individuals were assessed with ELISA and correlated with genotype.

RESULTS: The only SNP observed to be associated in both the pooled discovery and primary replication cohort was rs1014091, located upstream of the HGF gene. The nearby SNP rs3735520 was found to be associated in the individually typed discovery cohort (P = 6.1 {\texttimes} 10(-7)). Genotyping of tag SNPs around HGF revealed association at rs3735520 and rs17501108/rs1014091 in four of the five cohorts. Meta-analysis of all five datasets together yielded suggestive P values for rs3735520 (P = 9.9 {\texttimes} 10(-7)) and rs17501108 (P = 9.9 {\texttimes} 10(-5)). In addition, SNP rs3735520 was found to be associated with serum HGF level in normal individuals (P = 0.036).

CONCLUSIONS: Taken together, these results implicate genetic variation at the HGF locus with keratoconus susceptibility.

}, keywords = {Adult, Aged, Chromosomes, Human, Pair 7, Corneal Topography, Enzyme-Linked Immunosorbent Assay, Genetic Predisposition to Disease, Genome-Wide Association Study, Genotype, Hepatocyte Growth Factor, Humans, Keratoconus, Middle Aged, Nucleic Acid Hybridization, Polymorphism, Single Nucleotide, Promoter Regions, Genetic, Sequence Tagged Sites}, issn = {1552-5783}, doi = {10.1167/iovs.11-8261}, author = {Burdon, Kathryn P and Macgregor, Stuart and Bykhovskaya, Yelena and Javadiyan, Sharhbanou and Li, Xiaohui and Laurie, Kate J and Muszynska, Dorota and Lindsay, Richard and Lechner, Judith and Haritunians, Talin and Henders, Anjali K and Dash, Durga and Siscovick, David and Anand, Seema and Aldave, Anthony and Coster, Douglas J and Szczotka-Flynn, Loretta and Mills, Richard A and Iyengar, Sudha K and Taylor, Kent D and Phillips, Tony and Montgomery, Grant W and Rotter, Jerome I and Hewitt, Alex W and Sharma, Shiwani and Rabinowitz, Yaron S and Willoughby, Colin and Craig, Jamie E} } @article {6076, title = {Genetic association of COL5A1 variants in keratoconus patients suggests a complex connection between corneal thinning and keratoconus.}, journal = {Invest Ophthalmol Vis Sci}, volume = {54}, year = {2013}, month = {2013 Apr 12}, pages = {2696-704}, abstract = {

PURPOSE: Single nucleotide polymorphisms (SNPs) located near or within the COL5A1 gene, at 9q34.2-q34.3 chromosomal region have been reported in association with central corneal thickness (CCT). Using family linkage analysis, we identified a keratoconus susceptibility locus at 9q34. These findings led us to perform an association study between COL5A1 variation and keratoconus susceptibility.

METHODS: A Caucasian case-control cohort of 222 keratoconus patients and 3324 controls was selected as the discovery panel. An independent case-control panel of 304 cases and 518 controls and a family panel of 186 subjects were replicated for genotyping and association. Forty-four SNPs (21 for discovery and 23 for fine-mapping) spanning 300 kilobases in and around COL5A1 were genotyped and tested for genetic association. Logistic regression models implemented in PLINK were used to test for association in case controls. Generalized estimating equation models accounting for familial correlations implemented in genome-wide interaction analyses with family data were used for association testing in families.

RESULTS: Two CCT associated SNPs (rs1536482 and rs7044529 near and within COL5A1) were identified in the keratoconus discovery cohort (P values of 6.5 {\texttimes} 10(-3) and 7.4 {\texttimes} 10(-3)). SNP rs1536482 was replicated in the second case-control sample (P = 0.02), and SNP rs7044529 was replicated in a keratoconus family panel (P = 0.03). Meta P values of rs1536482 and rs7044529 in the keratoconus cohorts were 1.5 {\texttimes} 10(-4) (odds ratio [OR] = 1.30) and 2.9 {\texttimes} 10(-3) (OR = 1.39). After Bonferroni correction, the association of SNP rs1536482 remained significant (P = 6.5 {\texttimes} 10(-3)).

CONCLUSIONS: SNPs in the COL5A1 region, which regulate normal variation in CCT, may play a role in the thinning associated with keratoconus.

}, keywords = {Adult, Aged, Collagen Type V, Cornea, Corneal Topography, DNA, Female, Genetic Predisposition to Disease, Genome-Wide Association Study, Genotype, Humans, Keratoconus, Male, Microscopy, Acoustic, Middle Aged, Polymorphism, Single Nucleotide, Tomography, Optical Coherence}, issn = {1552-5783}, doi = {10.1167/iovs.13-11601}, author = {Li, Xiaohui and Bykhovskaya, Yelena and Canedo, Ana Laura Caiado and Haritunians, Talin and Siscovick, David and Aldave, Anthony J and Szczotka-Flynn, Loretta and Iyengar, Sudha K and Rotter, Jerome I and Taylor, Kent D and Rabinowitz, Yaron S} }