For example, targeted silencing of the HTR2A gene, which encodes the serotonin receptor 5-HT2A, using a noninvasive CRISPR-Cas9 system led to a marked reduction in both HTR2A expression and anxiety-like behavior in mice, directly demonstrating a functional role for gene repression in modulating anxiety [64]. The gene discussed is HTR2A; the disease is Anxiety.