Genetics vs chronic corneal mechanical trauma in the etiology of keratoconus. (January 2021)

• Record Type: Journal Article
• Authors: Rabinowitz, Yaron S.; Galvis, Virgilio; Tello, Alejandro; Rueda, Daniela; García, Juan Daniel
• Is Part Of: Experimental eye research. Volume 202(2021)
• Publication Date: 2021-01
• Subjects: Cornea -- Keratoconus -- Corneal diseases -- Corneal topography -- Corneal pachymetry; Ophthalmology -- Periodicals; Eye -- Periodicals; Œil -- Périodiques; Ophthalmology; Periodicals; Electronic journals; 612.8405
• DOI: 10.1016/j.exer.2020.108328
• Languages: English
• ISSNs: 0014-4835

Abstract

Abstract: Both genetic and environmental factors have been considered to play a role in the etiology keratoconus. Eye rubbing, and more recently eye compression due to sleeping position, have been identified to be highly related to the condition, and are present in a high percentage of patients. Today, the predominant model is that these factors can provide the "second hit" necessary to generate the condition in a genetically susceptible individual. In addition, the extremely high prevalence in Arab populations, where endogamy could play a role, the high concordance rate in monozygotic twins, and the presence of family history of the condition between 5 and 23% of cases, support a genetic influence. Segregation analysis studies suggest that keratoconus is a complex non-Mendelian disease. Results from linkage analysis, next generation sequencing studies and genome-wide association studies also have suggested that genetic factors are involved in the condition. Recently, it has been proposed that mechanical trauma (i.e. eye rubbing or eye compression at night), is a sine quanon condition for the onset of keratoconus, and quite possibly its only cause. There are various arguments for and against this hypothesis. Indeed, it is possible, as initially suggested around 55 years ago, that the term "keratoconus" include diverse phenotypically similar conditions, which are actually of different etiology. Highlights: Eye rubbing, and eye compression at night, are risk factors for keratoconus. They seem to trigger the condition in a genetically susceptible cornea. High prevalence where endogamy is customary, support a genetic influence. High concordance rate in twins, and family history, also suggest genetic factors. Uncommonly secondary keratoconus can be due only to tenacious eye rubbing.