Estimating the Genetic Contribution to Astigmatism and Myopia in the Mexican Population

Abstract

Astigmatism and myopia are two common ocular refractive errors that can impact daily life, including learning and productivity. Current knowledge suggests that the etiology of these conditions is the result of a complex interplay between genetic and environmental factors. Studies in populations of European ancestry have demonstrated a higher concordance of refractive errors in monozygotic (MZ) twins compared to dizygotic (DZ) twins. However, there is a lack of studies on genetically informative samples of multi-ethnic ancestry. This study aimed to estimate the genetic contribution to astigmatism and myopia in the Mexican population. A sample of 1399 families, including 243 twin pairs and 1156 single twins, completed a medical questionnaire about their own and their co-twin’s diagnosis of astigmatism and myopia. Concordance rates for astigmatism and myopia were estimated, and heritability and genetic correlations were determined using a bivariate ACE Cholesky decomposition method, decomposed into A (additive genetic), C (shared environmental) and E (unique environmental) components. The results showed a higher concordance rate for astigmatism and myopia for MZ twins (.74 and .74, respectively) than for DZ twins (.50 and .55). The AE model, instead of the ACE model, best fitted the data. Based on this, heritability estimates were .81 for astigmatism and .81 for myopia, with a cross-trait genetic correlation of rA = .80, nonshared environmental correlation rE = .89, and a phenotypic correlation of rP = .80. These results are consistent with previous findings in other populations, providing evidence for a similar genetic architecture of these conditions in the multi-ethnic Mexican population.

Building national patient registries in Mexico: insights from the MexOMICS Consortium

“…The first steps of this project have been previously described ( 37 ). The latest results include a study on myopia and astigmatism, revealing notably high heritability (over 80%) estimated for both conditions, accompanied by a substantial cross-trait genetic correlation ( 92 ). These findings are consistent with prior research conducted in other populations, suggesting that both traits are influenced by a shared set of genes.…”

“…One of the further goals of this project is to explore associations of genetic variants with other publicly relevant health conditions, as well as neuropsychiatric measures such as depression and anxiety symptoms. For instance, our latest published advance for this project ( 92 ) revealed a high prevalence of gastritis, colitis, overweight, allergic rhinitis, and gastroesophageal reflux, in addition to myopia and astigmatism. On the other hand, anxiety, depression, insomnia, migraine, attentional deficit/hyperactivity disorder, and obsessive-compulsive disorder were the mental health conditions with the highest occurrence.…”

TwinsMX: Exploring the Genetic and Environmental Influences on Health Traits in the Mexican Population

“…An additional objective of TwinsMX is the public outreach of the benefits of twin studies, and to disseminate the scientific findings among participants and the general public. For instance, current TwinsMX results for eye health have shown that astigmatism and myopia in Mexican population has an heritability higher than 60% (Román-López et al, 2023), which shows that genetic factors are contributing more for these traits.…”