Last reviewed: May 12, 2026 Last updated: May 12, 2026

Written by: Jay Hastings , CEO of PlexusDx

Jay Hastings is the CEO of PlexusDx, a precision health company focused on genetic testing, blood biomarker insights, and personalized wellness recommendations. He has more than 20 years of experience across healthcare innovation, genomics, laboratory operations, healthcare investing, and strategic finance. His work has included scaling healthcare startups, leading CLIA lab integrations, and helping expand consumer access to precision health tools.

Medically reviewed by: Jayden Lee, PharmD, EMBA

Jayden Lee, PharmD, EMBA, is the PlexusDx Medical Science Liaison with a PharmD and MBA specializing in pharmacogenomics and clinical product development, with a proven ability to bridge the gap between genomic research and practical patient outcomes. Dr. Lee has more than 10 years of professional experience in clinical pharmacy, academia, and research.

This article is part of the PlexusDx Education Hub — your resource for evidence-based guidance on immune & infection health. Browse all Immune & Infection Health education

Most people treated promptly for Lyme disease recover fully. But a subset continue to experience fatigue, pain, and cognitive difficulties for months after antibiotics — a pattern often called chronic Lyme disease or post-treatment Lyme disease syndrome (PTLDS). Researchers are examining why some people are more vulnerable, and one gene under study is ABCB1, also known as MDR1.

This article explains what ABCB1 does, how it fits into the body's clearance and barrier pathways, and what current research does — and does not — support.

Understanding chronic Lyme disease and PTLDS

Lyme disease is caused by Borrelia burgdorferi bacteria transmitted through tick bites. Standard antibiotic treatment resolves the infection for most people. PTLDS describes lingering symptoms — fatigue, joint and muscle pain, and difficulty concentrating — that persist after treatment. Its biological mechanisms are still debated and actively researched; it is not fully understood, and no genetic test diagnoses it.

What the ABCB1 (MDR1) gene does

ABCB1 encodes P-glycoprotein (P-gp), a transporter that sits in cell membranes and pumps a wide range of substances out of cells. P-gp is highly active at protective barriers such as the blood-brain barrier and the intestinal lining, where it helps keep foreign compounds and cellular waste from accumulating. In essence, it is one of the body's molecular bouncers, exporting substances the cell wants to keep out or remove.

How ABCB1 connects to clearance and barrier pathways

Because P-glycoprotein participates in exporting xenobiotics and various cellular byproducts, ABCB1 sits within the body's broader detoxification and barrier-integrity pathways. Common variants — such as rs1045642 (also called C3435T) — are associated with differences in how much P-gp a person produces and how actively it works. In principle, variation in this efflux capacity could influence how efficiently cells clear certain bacterial products, which is why researchers have taken an interest in ABCB1 in the context of persistent infection symptoms.

What research suggests so far

It is important to be candid: the evidence connecting ABCB1 specifically to chronic Lyme disease is early and limited. ABCB1's role in cellular transport and barrier function is well established, but its direct contribution to PTLDS remains a research hypothesis rather than a settled finding. No variant has been shown to cause chronic Lyme disease, and susceptibility to persistent symptoms is almost certainly multifactorial — involving immune response, the timing of treatment, and individual biology together.

Working with a provider

Anyone concerned about a tick bite, active Lyme disease, or lingering post-treatment symptoms should work with a qualified healthcare provider. Diagnosis and treatment of Lyme disease rest on clinical evaluation and established testing, and decisions about antibiotics or symptom management belong entirely with a physician. Genetic information does not change that and should never be used to self-direct medication choices.

What pathway-level genetic insight offers

A genetic test cannot diagnose Lyme disease, cannot predict who will develop chronic symptoms, and does not tell you which medication to take. What it can offer is pathway-level context about your biology. The Precision Peptide Genetic Test analyzes 14 pathways, 49 peptides, 150+ genetic insights across peptide-related biological pathways — including transport and cellular-clearance biology where genes like ABCB1 operate. It reports how your body is wired at the pathway level, not a diagnosis or a drug recommendation, giving you informed context for a conversation with your provider. Genetics is a guide, not a guarantee. Related reading: why some people get infections more often.

Frequently Asked Questions

Does the ABCB1 gene cause chronic Lyme disease?

No. No gene has been shown to cause chronic Lyme disease or PTLDS. ABCB1's role in cellular transport makes it a subject of research interest, but susceptibility to persistent symptoms is multifactorial, involving immune response, treatment timing, and individual biology. The ABCB1 evidence remains early and unproven.

Can a genetic test tell me which antibiotic to take?

No. The Precision Peptide Genetic Test is not a pharmacogenomic test and does not predict response to any medication or recommend a drug or dose. It provides pathway-level insight into your biology only. All decisions about antibiotics belong with a qualified healthcare provider.

What does P-glycoprotein do?

P-glycoprotein, encoded by ABCB1 (MDR1), is a transporter that pumps substances out of cells. It is especially active at protective barriers like the blood-brain barrier and gut lining, where it helps export foreign compounds and cellular waste as part of the body's clearance and barrier-integrity pathways.

Is chronic Lyme disease genetic?

Not in any simple way. Risk factors for persistent post-treatment symptoms appear multifactorial, and genetics is likely only a small piece alongside immune function and how early the infection was treated. There is no single gene test for chronic Lyme, and current genetic links are research-stage, not diagnostic.

Want pathway-level context on your transport and clearance biology? Take the Precision Peptide Genetic Test.

This article is part of the PlexusDx Education Hub. Browse all Immune & Infection Health education

The Precision Peptide Genetic Test analyzes how your genes influence peptide-related biological pathways. It does not recommend, prescribe, or determine which peptides you should use. Consult a qualified healthcare provider before beginning any peptide protocol.

Medical and Editorial Standards

Medical review process: This article was reviewed for medical accuracy, scientific clarity, evidence alignment, and appropriate discussion of genetics, medications, supplements, biomarkers, and health-related claims.

Sources and evidence: PlexusDx educational content is developed using peer-reviewed research, clinical literature, reputable medical references, and, where applicable, public health or regulatory guidance. References are included at the end of the article when scientific, medical, or health-related claims are discussed.

Commercial transparency: PlexusDx offers genetic testing, blood biomarker testing, personalized supplement recommendations, and related precision wellness services. Product mentions are intended to help readers understand available options and should not be interpreted as medical advice.

Important disclaimer: PlexusDx educational content is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about medications, supplements, genetic testing, lab testing, or health-related care.