Heritability of Ocular Traits in Hispanics: Findings from the Maracaibo Aging Study

Abstract

Purpose : The burden of incurable eye disease such as glaucoma among Hispanics is significantly higher than in their white counterparts. It is not known to what extent these differences are determined by genetic factors in Hispanics; thus we examined a highly inbred population in Venezuela to estimate the proportion of the total observed variance attributable to additive genetic factors, of ocular traits relevant to common complex ocular diseases.

Methods : A subset of 110 participants ≥ 40y from the Maracaibo Aging Study (MAS) was randomly selected from an extended pedigree to participate in this pilot study. Experienced ophthalmologists performed a standardized clinical assessment that included estimation of intraocular pressure with Goldmann tonometry, fundus photography, standard automated perimetry performed with the Heidelberg Edge Perimeter and measurement of the thickness of peripapillary retinal nerve fiber layer (RNFL) with Spectralis SD-OCT. Heritability analyses (h², expressed as %) were performed using the variance components approach as implemented in the software package, Sequential Oligogenic Linkage Analysis Routines (SOLAR). A likelihood ratio test was used to test whether the heritability of a given phenotype was significantly (P<0.05) greater than zero. The covariates, age, sex, and their interactions were controlled for in the analysis.

Results : Sixty-seven individuals, all from a single extended pedigree, completed all the assessments. Total RNFL thickness (h²=0.84; P<0.004), as well as thickness of the superior (h²=0.60; P<0.01), inferior (h²=0.81; P<0.02), and temporal (h²=0.86; P<0.004), quadrants had statistically significant heritabilities. Macular thickness at the fovea was highly heritable ((h²=0.71; P<0.02). When dissected into quadrants were assessed, only inner quadrants were significantly heritable. IOP was not significantly heritable.

Conclusions : Several heritability estimates of heritability in this population awere in the moderate to high range, consistent with findings in other ethnic groups. suggesting this highly inbred cohort may provide insight into the Considering that to date the majority of genetic variants accounting for these findings have not been uncovered, the MAS constitute a valuable resource in efforts to elucidate the molecular basis of etiology ofthe intermediate ocular traits, which in turn may explain underlying causes of glaucoma and AMD such heritabilities.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.