rs504073
Variant in the HRH2 gene (Histamine Receptor H2)
rs504073 is a single nucleotide polymorphism (SNP) in the HRH2 gene, involved in histamine signaling. Variants at this position have been studied in relation to immune function, metabolism, and chronic illness.
This page is for educational and informational purposes only. Not a diagnostic tool. Always consult a qualified healthcare provider.
What is the rs504073 variant?
rs504073 is a SNP (single nucleotide polymorphism) in the HRH2 (Histamine Receptor H2) gene. 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
This variant sits within the HRH2 gene, which is involved in the histamine signaling pathway. 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 — particularly under conditions of physiological stress such as viral infection or prolonged illness.
rs504073 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.
Parent gene: HRH2
rs504073 is one of 3 known variants in the HRH2 gene. To understand the full biological context of this variant, explore the parent gene page.
View HRH2 gene page →Conditions studied in relation to rs504073
Research into HRH2 variants including rs504073 has explored associations with the following conditions. These are areas of scientific investigation and do not imply causation.
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 the rs504073 variant.
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.
Other variants in the HRH2 gene
The following variants in HRH2 are also studied in relation to chronic illness and may be analysed together for a more complete picture.
Frequently asked questions
What is the rs504073 variant in the HRH2 gene?
rs504073 is a single nucleotide polymorphism (SNP) located in the HRH2 (Histamine Receptor H2) gene, which 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 the rs504073 variant 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 consumer DNA test detect the rs504073 variant?
Many consumer DNA tests such as 23andMe, AncestryDNA, and MyHeritage genotype common SNPs. ChronicDNA analyses your raw DNA file and reports on variants studied in relation to chronic illness, immune function, and metabolism. This is not a diagnostic service — results are informational and educational only.
Find out if you carry the rs504073 variant
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 and its variants. This is not an exhaustive literature review.
- [1]PMID: 32311998
- [2]Gut
- [3]Journal of Pharmacology and Experimental Therapeutics