HRH2 Gene
Histamine Receptor H2 (HRH2) is a gene involved in histamine signaling that has been studied in relation to immune function, metabolism, and chronic illness. Variants in HRH2 may influence how the body responds to infection, inflammation, and long-term recovery.
This page is for educational and informational purposes only. Not a diagnostic tool. Always consult a qualified healthcare provider.
What is the HRH2 gene?
HRH2 encodes histamine receptor h2, a protein involved in histamine signaling. It belongs to the Pharmacology category and is part of the Adaptive Immunity biological cluster. HRH2 mediates histamine's effects on gastric acid secretion and cardiac stimulation. H2 blockers (famotidine, ranitidine) reduce gastric acid production and have been investigated for COVID-19 and Long COVID.
Biological role and pathway
HRH2 is involved in the histamine signaling pathway, which plays a central role in regulating physiological processes relevant to immune defence, cellular energy, and systemic homeostasis. Genes within the Adaptive Immunity 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.
HRH2 and Long COVID / ME-CFS research
Famotidine showed early promise in COVID-19 treatment. In Long COVID, H2 blocker benefit may extend beyond histamine to effects on immune signaling through histamine-cAMP-PKA pathways. HRH2 variants affecting cAMP responses may influence immune regulation in Long COVID.
This information is based on published research and does not constitute medical advice. See references below.
Known genetic variants
The following variants (SNPs) in the HRH2 gene have been studied in relation to pharmacology and chronic illness. Each variant represents a single nucleotide position where individuals may carry different alleles.
Conditions studied in relation to HRH2
Research into HRH2 variants has explored associations with the following conditions. These are areas of scientific investigation and do not imply that HRH2 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 HRH2 and related genes in the adaptive immunity 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 Adaptive Immunity pathway
HRH2 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
What is the HRH2 gene and what does it do?
HRH2 (Histamine Receptor H2) is involved in histamine signaling. HRH2 mediates histamine's effects on gastric acid secretion and cardiac stimulation. H2 blockers (famotidine, ranitidine) reduce gastric acid production and have been investigated for COVID-19 and Long COVID.
How may HRH2 gene variants relate to Long COVID or ME/CFS?
Famotidine showed early promise in COVID-19 treatment. In Long COVID, H2 blocker benefit may extend beyond histamine to effects on immune signaling through histamine-cAMP-PKA pathways. HRH2 variants affecting cAMP responses may influence immune regulation in Long COVID.
Can a DNA test reveal information about my HRH2 gene?
Consumer DNA data from 23andMe, AncestryDNA, and MyHeritage includes SNP variants for many genes. ChronicDNA analyses your raw DNA file and reports on variants that have been studied in relation to chronic illness, immune function, and metabolism. This is not a diagnostic service — results are informational and educational only.
Explore your HRH2 genetic insights
Upload your DNA data from 23andMe, AncestryDNA, or MyHeritage and receive a personalised report covering >80 genes relevant to Long COVID and ME/CFS.
Get Your Personalised DNA ReportInformational and educational only · Not a diagnostic tool · GDPR compliant
References
The following publications were used in compiling the research context for HRH2. This is not an exhaustive literature review.
- [1]PMID: 32311998
- [2]Gut
- [3]Journal of Pharmacology and Experimental Therapeutics