Assessment of TGIF as a candidate gene for myopia.
OBJECTIVE
Transforming growth beta-induced factor (TGIF) has been identified as a candidate gene for high myopia through genetic linkage studies and through its role in ocular growth in animal studies. However, the association of single nucleotide polymorphisms (SNPs), based solely on myopia refraction, has so far been inconclusive. This is the first study conducted to investigate the association of TGIF with refraction and ocular biometric measurements.


METHODS
Twelve tag SNPs (tSNPs) encompassing the TGIF gene and 2 kb upstream of its promoter region were used to evaluate the association between TGIF variants with both ocular biometric measures and refraction. A total of 257 cases of myopia (spherical equivalent [SE] worse than -0.50 D) and 294 control subjects (no myopia) were genotyped. Genotype frequencies were analyzed by chi(2) test and one-way ANOVA.


RESULTS
Two tSNPs showed significant association with biometric measures, with the SNP rs8082866 being associated with both axial length (P = 0.013) and corneal curvature (P = 0.007) and the SNP rs2020436 being associated with corneal curvature (P = 0.022). However, these associations became nonsignificant after multiple testing (Bonferroni correction).


CONCLUSIONS
Findings of this study suggest that the TGIF gene is unlikely to play a major role in either ocular biometric measures or refraction in a Caucasian population. Future studies should focus on other genes in the MYP2 linkage region or other linked regions to identify myopia-causing genes.
Pertile
Kelly K
KK
Centre for Eye Research Australia, Department of Ophthalmology University of Melbourne, 32 Gisborne Street, East Melbourne, Victoria, Australia. kpertile@unimelb.edu.au
Schäche
Maria
M
Islam
F M Amirul
FM
Chen
Christine Y
CY
Dirani
Mohamed
M
Mitchell
Paul
P
Baird
Paul N
PN
D001699:Biometry; D016022:Case-Control Studies; D003315:Cornea / Q000473:pathology; D005123:Eye / Q000473:pathology; D005260:Female; D005838:Genotype; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000145:classification / Q000235:genetics* / Q000473:pathology; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012029:Refraction, Ocular; D012097:Repressor Proteins / Q000235:genetics*
D018398:Homeodomain Proteins; D012097:Repressor Proteins; C097504:TGIF1 protein, human