CHI3L1 and asthma: The highest serum concentration of YKL-40 was found in patients with asthma, independent of their status of rhinitis, with the SNP −131 CC genotype, and the lowest serum concentration of YKL-40 in patients with asthma with the SNP −131 GG genotype (median [min–max]: 46 μg/L [16–280 μg/L] vs. 19 μg/L [10–44 μg/L], p<0.0001) (Table 3).