AIM:To explore the effect of genetic factors on the pathogenesis of keratoconus and its genetic model.

METHODS: Genetic epidemiological methods were used to investigate the prevalence of keratoconus in 280 first-degree relatives of 100 patients with keratoconus who attended Henan Eye Hospital between July 2020 and April 2023. The heritability was estimated by Falconer regression method. The general genetic model was calculated using Penrose method, and the genetic model was confirmed by Falconer formula, Edwards approximation formula and the projection formula of San-Duo Jiang's threshold model theory.

RESULTS: The results showed that there were 16(5.714%)first-degree relatives of keratoconus probands suffering from keratoconus, and the heritability of keratoconus was(86.100±7.400)%. The S/q score calculated by the Penrose method was 35.348, which was near to 1/(q)^1/2, suggesting that the genetic model of keratoconus might be polygenic inheritance. The expected prevalence in first-degree relatives of keratoconus patients by Falconer formula, Edwards approximation formula and the projection formula of San-Duo Jiang's threshold model theory were 5.900%, 7.714% and 5.700%, respectively, which showed no significant differences from the actual prevalence(5.714%), suggesting that keratoconus was a polygenetic disease.

CONCLUSION:Genetic factors might play an important role in the pathogenesis of keratoconus, and keratoconus is a polygenetic disease.