Purpose:
To test the hypotheses of major genetic determinants of Vertical Disc Diameter (VDD) and Vertical Cup/Disc Ratio (VCDR) under the mixed genetic model in a defined population.
Methods:
VDD and VCDR were determined by planimetry from stereo optic disc photographs in the 3654 persons attending the Blue Mountains Eye Study. After adjustment for covariates where appropriate, commingling analysis was performed on VDD and VCDR using the program SKUDRIVER1. The goodness of fit of 1–, 2– and 3–distribution models was measured using the Akaike Information Criterion (AIC).
Results:
The best models for both VDD and VCDR were 3–distribution. Model parameters are as in the Table. There was no evidence for Hardy–Weinberg disequilibrium.
Conclusions:
The findings of this study are consistent with the presence of a major overdominant gene accounting for 22% of the variance of VDD, and a major codominant gene accounting for 59% of the variance of VCDR in this population. These findings suggest methods of optimizing strategies to identify quantitative trait loci for VDD and VCDR, which are important components of the glaucoma phenotype. 1Viswanathan AC, Hitchings RA, Indar A, Mitchell P, Healey P, McGuffin P, Sham PC. Commingling analysis of intraocular pressure and glaucoma in an older Australian population. Annals of Human Genetics 2004 Sep;68(Pt 5):489–97
Keywords: optic disc • genetics • clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology