rs2046631
Variant in the HDC gene (Histidine Decarboxylase)
rs2046631 is a single nucleotide polymorphism (SNP) in the HDC gene, involved in histamine synthesis. 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 rs2046631 variant?
rs2046631 is a SNP (single nucleotide polymorphism) in the HDC (Histidine Decarboxylase) gene. It belongs to the Metabolism category and is part of the Adaptive Immunity biological cluster. HDC catalyzes the decarboxylation of histidine to histamine, representing the sole biosynthetic pathway for histamine. It is expressed in mast cells, basophils, enterochromaffin-like cells, and neurons.
Biological role and pathway
This variant sits within the HDC gene, which is involved in the histamine synthesis 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.
rs2046631 and Long COVID / ME-CFS research
Elevated histamine synthesis in activated mast cells contributes to Long COVID histamine symptoms. HDC variants affecting histamine biosynthesis rate may interact with degradation variants (HNMT, AOC1) to determine net histamine load and symptom severity in Long COVID.
This information is based on published research and does not constitute medical advice. See references below.
Parent gene: HDC
rs2046631 is one of 3 known variants in the HDC gene. To understand the full biological context of this variant, explore the parent gene page.
View HDC gene page →Conditions studied in relation to rs2046631
Research into HDC variants including rs2046631 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 HDC and the rs2046631 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 HDC gene
The following variants in HDC are also studied in relation to chronic illness and may be analysed together for a more complete picture.
Frequently asked questions
What is the rs2046631 variant in the HDC gene?
rs2046631 is a single nucleotide polymorphism (SNP) located in the HDC (Histidine Decarboxylase) gene, which is involved in histamine synthesis. HDC catalyzes the decarboxylation of histidine to histamine, representing the sole biosynthetic pathway for histamine. It is expressed in mast cells, basophils, enterochromaffin-like cells, and neurons.
How may the rs2046631 variant relate to Long COVID or ME/CFS?
Elevated histamine synthesis in activated mast cells contributes to Long COVID histamine symptoms. HDC variants affecting histamine biosynthesis rate may interact with degradation variants (HNMT, AOC1) to determine net histamine load and symptom severity in Long COVID.
Can a consumer DNA test detect the rs2046631 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.
Related articles
- Long COVID MCAS: Mast Cells, Histamine and Your Genes
Learn how Long COVID MCAS may develop, how it overlaps with POTS and histamine intolerance, and which genes research links to mast cell activity.
Find out if you carry the rs2046631 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 HDC and its variants. This is not an exhaustive literature review.
- [1]PMID: 29282753
- [2]Frontiers in Immunology
- [3]Journal of Allergy and Clinical Immunology