Genetics of Sarcoidosis
SEMINARS IN RESPIRATORY AND CRITICAL CARE MEDICINE
Authors: Fischer, Annegret; Grunewald, Johan; Spagnolo, Paolo; Nebel, Almut; Schreiber, Stefan; Mueller-Quernheim, Joachim
Abstract
Sarcoidosis is a multifactorial and polygenic disorder. Recently, several novel predisposing genes have been identified by genome-wide association studies, and fast progress in molecular technologies such as systematic and large-scale resequencing will aid the discovery of further risk loci and variants. In this article, the current knowledge of its genetics will be presented, including known and candidate risk variants and loci, with a focus on loci in the human leukocyte antigen region. Some of these factors are shared with other, clinically distinct diseases. This May lead to the development of new hypotheses on pathomechanisms, which associate sarcoidosis with other granulomatous disorders but also with diseases with significantly different phenotypes. In the near future system, biology approaches. will help unravel the differing and common features of these disorders and allow the development of new therapeutic Strategies and tools to predict the course and response to treatment of individual patients.
Exomic Sequencing of Immune-Related Genes Reveals Novel Candidate Variants Associated with Alopecia Universalis
PLOS ONE
Authors: Lee, Seungbok; Paik, Seung Hwan; Kim, Hyun-Jin; Ryu, Hyeong Ho; Cha, Soeun; Jo, Seong Jin; Eun, Hee Chul; Seo, Jeong-Sun; Kim, Jong-Il; Kwon, Oh Sang
Abstract
Alopecia areata (AA) is a common autoimmune disorder mostly presented as round patches of hair loss and subclassified into alopecia totalis/alopecia universalis (AT/AU) based on the area of alopecia. Although AA is relatively common, only 5% of AA patients progress to AT/AU, which affect the whole scalp and whole body respectively. To determine genetic determinants of this orphan disease, we undertook whole-exome sequencing of 6 samples from AU patients, and 26 variants in immune-related genes were selected as candidates. When an additional 14 AU samples were genotyped for these candidates, 6 of them remained at the level of significance in comparison with 155 Asian controls (p<1.92610(-3)). Linkage disequilibrium was observed between some of the most significant SNPs, including rs41559420 of HLA-DRB5 (p<0.001, OR 44.57) and rs28362679 of BTNL2 (p<0.001, OR 30.21). While BTNL2 was reported as a general susceptibility gene of AA previously, HLA-DRB5 has not been implicated in AA. In addition, we found several genetic variants in novel genes (HLA-DMB, TLR1, and PMS2) and discovered an additional locus on HLA-A, a known susceptibility gene of AA. This study provides further evidence for the association of previously reported genes with AA and novel findings such as HLA-DRB5, which might represent a hidden culprit gene for AU.