CFI Gene

Complement Factor I (CFI) is a gene involved in complement regulation that has been studied in relation to immune function, metabolism, and chronic illness. Variants in CFI 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 CFI gene?

CFI encodes complement factor i, a protein involved in complement regulation. It belongs to the Immune Signaling category and is part of the Coagulation & Microcirculation biological cluster. CFI encodes complement factor I, a serine protease that inactivates C3b and C4b to prevent uncontrolled complement activation.

Biological role and pathway

CFI is involved in the complement regulation pathway, which plays a central role in regulating physiological processes relevant to immune defence, cellular energy, and systemic homeostasis. Genes within the Coagulation & Microcirculation 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.

CFI and Long COVID / ME-CFS research

CFI deficiency leads to complement dysregulation and increased susceptibility to infections; variants may affect complement control and vascular injury 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 CFI gene have been studied in relation to immune signaling and chronic illness. Each variant represents a single nucleotide position where individuals may carry different alleles.

Conditions studied in relation to CFI

Research into CFI variants has explored associations with the following conditions. These are areas of scientific investigation and do not imply that CFI 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 CFI and related genes in the coagulation & microcirculation 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 Coagulation & Microcirculation pathway

CFI 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 CFI gene and what does it do?

CFI (Complement Factor I) is involved in complement regulation. CFI encodes complement factor I, a serine protease that inactivates C3b and C4b to prevent uncontrolled complement activation.

How may CFI gene variants relate to Long COVID or ME/CFS?

CFI deficiency leads to complement dysregulation and increased susceptibility to infections; variants may affect complement control and vascular injury in Long COVID.

Can a DNA test reveal information about my CFI 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 CFI 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 Report

Informational and educational only · Not a diagnostic tool · GDPR compliant

References

The following publications were used in compiling the research context for CFI. This is not an exhaustive literature review.

  • [1]PMID: 32966261
  • [2]Nature Genetics
  • [3]NEJM