HTR3A Gene

What is the HTR3A gene?

HTR3A encodes 5-hydroxytryptamine receptor 3a, a protein involved in serotonin / ligand-gated ion channel. It belongs to the Neurotransmitter category and is part of the Histamine & MCAS biological cluster. HTR3A encodes the 5-HT3A subunit of the 5-HT3 receptor, a ligand-gated ion channel mediating fast serotonin signaling in the gut-brain axis.

Biological role and pathway

HTR3A is involved in the serotonin / ligand-gated ion channel pathway, which plays a central role in regulating physiological processes relevant to immune defence, cellular energy, and systemic homeostasis. Genes within the Histamine & MCAS cluster work together to maintain balanced function across interconnected biological systems.

Variants in genes within this pathway may influence an individual's predisposition to altered function in these systems — particularly under conditions of physiological stress such as viral infection or prolonged illness.

Known genetic variants

The following variants (SNPs) in the HTR3A gene have been studied in relation to neurotransmitter and chronic illness. Each variant represents a single nucleotide position where individuals may carry different alleles.

• rs1062613— HTR3A variant
• rs33940208— HTR3A variant

Conditions studied in relation to HTR3A

Research into HTR3A variants has explored associations with the following conditions. These are areas of scientific investigation and do not imply that HTR3A causes or treats any condition.

Genetic insights from DNA data

Consumer DNA files from 23andMe, AncestryDNA, and MyHeritage contain raw SNP data. When you upload your file to ChronicDNA, the analysis engine checks your genotype against a curated panel of 80+ genes selected for their relevance to Long COVID, ME/CFS, and connected biological pathways - some of which may include HTR3A and related genes in the histamine & mcas pathway.

The report is educational - it explains which variants you carry, what the research says about them, and how they fit into the biological pathways most relevant to chronic illness. Results are presented in plain English with appropriate scientific context, no medical jargon, no scare tactics. All results should be discussed with a qualified healthcare provider.

Related genes in the Histamine & MCAS pathway

HTR3A does not act in isolation. The following genes are functionally related and may be analysed together for a more complete picture of your genetic predispositions.

Frequently asked questions