Consanguineous Marriage as a Risk Factor for Developing Keratoconus

Heredity plays an important role in keratoconus (KC). Consanguineous marriage (CM) can affect the transmission of recessively inherited conditions. We aimed to investigate the role of consanguineous marriage in the development of KC. This study included two groups: the first group comprised 415 patients who underwent surgery for KC for the first time at Khalili University Hospital (Shiraz, Iran), between 2010 and 2014; the second group comprised 415 healthy individuals who served as age- and sex-matched controls for the patient group. All study subjects were from the Fars province in Iran. CM type was evaluated by a standard checklist in both groups. The mean inbreeding coefficient (α) was evaluated and compared between the two groups. The percentage of parental first-cousin marriages was 35.4% in the patient group and 18.3% in the control group. The mean inbreeding coefficient (α) was 0.0291 in the patient group and 0.0135 in the control group. Patients with KC had a significantly higher mean inbreeding coefficient (α) than controls (T = 8, df = 828, P < 0.001). Our study suggests that CM can play a role in the pathogenesis of KC. As this disease is among the most frequent ocular disorders in our country, CM should be considered by health care systems within their screening programs.