CHI3L1 and asthma: Recently, with numerous advances in genetic research, many genetic variants regulating the expression of proteins involved in the development of asthma have been found to be related to susceptibility to this disease, including interleukin-17F (IL-17F), toll-like receptor 4 (TLR4), and the genes encoding chitinase 3–like 1 (CHI3L1) and acidic mammalian chitinase (AMCase or CHIA) [5–8].