BTNL2 and asthma: Moreover, 15 other genes have been associated with one member phenotype, and 10 of these (BRD2, BTNL2, CDSN, CFB, HCP5, HLA-DOA, MICB, NOTCH4, PBX2, PSORS1C1) have been associated with asthma across four studies (Hirota et al. 2011; Tomer et al. 2015; Almoguera et al. 2017; Demenais et al. 2018).