HTR2A and diabetes mellitus: Other studies have suggested that this is mainly related to a range of aging, metabolism, and inflammation-related diseases, such as cancer, diabetes, and others (5, 6).Of interest, the HTR2A gene (encoding 5-hydroxytryptamine receptor 2A [5-HT2A, also known as HTR2A]) is one of the serotonin receptors that are neurotransmitters with multiple actions, and there are numerous studies demonstrating the specific and significant correlation of this gene to SCZ (7–9).