As candidate genes, this study selected three serotonin (5-HT) receptor genes htr1Aa, htr1B, and htr2B, as well as the two 5-HT transporter genes slc6a4a and slc6a4b for their involvement in the regulation of the serotonergic system and in anxiety related behaviors [74–76]. The gene discussed is HTR2B; the disease is Anxiety.