Moreover, non-severe and severe asthma patients differed significantly in the distribution of allele G carriers versus CC homozygotes (p = 0.004) of the 5HT2C rs518147 polymorphism, demonstrating that the carriers of CC genotype or C allele were significantly less frequent in severe asthma patients in comparison to carriers of the G allele. This evidence concerns the gene HTR2C and asthma.