TGFB1 and asthma: In mice, an overdose of TGFB1 transmission resulted in disruption of epithelial differentiation and inhibitory synthesis of the Clara cell secretory protein, phospholipids, and surface proteins A, B, and C. In humans, the T allele of the SNP rs1800469 in the promoter region of the TGFB1 gene has been associated with phenotypes related to asthma (Silverman et al., 2004), and TGFB1 levels in the airways of asthmatics are reported to be higher than in normal subjects (Nakao, 2001).