Sarcoidosis is a complex disorder with a strong genetic background (3–5), for which a number of genetic risk factors have been identified by genome-wide association and candidate gene studies, e.g., various HLA-haplotypes (6), BTNL2 (7), ANXA11 (8), and IL23R (9), some of which confer susceptibility to certain sarcoidosis phenotypes (10). This evidence concerns the gene BTNL2 and sarcoidosis.