SP140 and obstructive sleep apnea syndrome: Although aberrant DNA methylation in the promoter regions of several inflammation-related genes such as IL1R2 (interleukin 1 receptor 2), AR (androgen receptor), NPR2 (natriuretic peptide receptor 2), and SP140 (speckled protein 140) genes have been reported in patients with OSA [15], little is known about the role of DNA methylation over the TLR genes in the development of OSA and its clinical phenotypes.