Posters

Familial risk of keratoconus among first-degree relatives – a population-based aggregation study in Korea

Poster Details

First Author: K.Na SOUTH KOREA

Co Author(s):    K. Na   S. Yi   S. Kim   B. Ha   S. Kazmi   H. Ahn     

Abstract Details

Purpose:

Few studies have reported a genetic predisposition in keratoconus (KC). However, population-level familial risk estimates are generally not available. In this study, we aimed to quantify the incidence and familial risk of KC among first-degree relatives (FDRs) of individuals with KC.

Setting:

This population-based longitudinal observational cohort study leveraged data from the Korean National Health Insurance (NHI) database, which has complete population coverage and family relationship information of over 50 million residents.

Methods:

Using the NHI database, we constructed a cohort of 21,940,795 individuals comprising 12 million distinct family units consisting of husband, wife and their biological offspring. All study subjects were followed up from 2002 to 2018 for a familial occurrence of KC. We estimated the familial risk by calculating the incidence risk ratio in individuals with affected FDR compared to those without affected FDR.

Results:

Among the study population of 22 million, there were 32,561 people with affected FDR, from whom 422 familial cases developed KC with an incidence of 8.6 per 10,000 person-years. In others without affected FDR, 15,026 non-familial cases developed the disease with an incidence of 0.44 per 10,000 person-years. Correspondingly, the familial risk for KC was 20-fold higher in individuals with versus without affected FDR. The familial risk of KC was associated with the degree of genetic relatedness, being highest in individuals with affected twins (169-fold), followed by individuals with affected siblings (26-fold), mothers (6-fold), and fathers (4-fold).

Conclusions:

This study represents the largest familial aggregation study of KC and demonstrated substantially increased risk among FDRs of affected individuals. Our findings suggest a significant genetic component in the etiology of KC, with the contribution of environmental factors as well. Higher familial risk in siblings, especially in twins compared to offspring of affected parents is suggestive of a recessive inheritance pattern in KC. We hope that these results will be useful for risk counseling of patients in clinical setting and will serve to direct future genetic studies on KC.

Financial Disclosure:

None