Abstract
Purpose :
Sarcoidosis is a chronic systemic disease characterized by the accumulation of non-caseating granulomas in a wide range of organs. The clinical features of sarcoidosis vary among different ethnic groups, and ocular and cardiac involvements are more common in Japan. The etiology of sarcoidosis is still uncertain, but the disease is currently thought to be triggered by various genetic as well as environmental factors. It is well established that sarcoidosis is strongly associated with the human leukocyte antigen (HLA) class II alleles in many different ethnic groups. In this study, we performed a comprehensive association analysis between the HLA region and ocular involvement in sarcoidosis.
Methods :
We used the SNPs in the HLA region genotyped in the genome-wide association study which enrolled 700 Japanese sarcoidosis patients and 886 Japanese controls using Illumina HumanOmniExpress (727,413 SNPs). After sample and SNP quality control, a total of 3,262 SNPs in the HLA region from 685 patients (including 519 patients with ocular involvement) and 847 controls were used for subsequent statistical analyses.
Results :
We identified two HLA class II loci showing a strong association with ocular sarcoidosis (P < 1.0 × 10-6, OR > 1.40) but not non-ocular sarcoidosis (P > 0.05, OR < 1.0). Although the physical distance between these loci is about 200 kb, they were in weak linkage disequilibrium with each other (r2 = 0.12) and were independently associated with ocular sarcoidosis.
Conclusions :
This study identified two independent risk loci in the HLA class II region for ocular involvement in Japanese patients with sarcoidosis. To confirm the findings, future validation studies with other independent populations are needed.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.