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 genetics & health. Browse all Genetics & Health education

Alopecia areata is an autoimmune form of hair loss in which the immune system mistakenly attacks hair follicles. It has a strong genetic component, and much of that genetic signal clusters in one region of the genome — the human leukocyte antigen, or HLA, complex. Here is what variants like those in HLA-DQA2 tell researchers.

What alopecia areata is

Alopecia areata causes patchy hair loss, most often on the scalp, when immune cells surround and disrupt hair follicles. It affects an estimated 2% of people at some point in life and can appear at any age. The condition is not contagious, and hair follicles are usually not destroyed, which is why regrowth is possible. Because it is autoimmune, its genetic roots overlap with those of other autoimmune conditions.

Why the HLA region matters in autoimmunity

The HLA complex, on chromosome 6, contains the genes that help your immune system tell "self" from "non-self." HLA molecules present fragments of proteins to immune cells so the body can decide whether to react. Small differences in these genes change which fragments are presented and how strongly, which is why the HLA region shows up as the top genetic association for many autoimmune diseases — including alopecia areata.

HLA-DQA2 and related variants

Genome-wide association studies of alopecia areata have repeatedly flagged class II HLA genes, including HLA-DQA2 along with HLA-DQB1 and HLA-DRB1. HLA-DQA2 encodes part of an MHC class II molecule involved in presenting antigens to helper T cells. Specific variants in and around this gene are associated with higher risk, and the HLA signal is among the strongest for the condition. These variants shift immune-recognition tendencies — they do not guarantee that alopecia areata will develop.

Beyond HLA: other immune genes

HLA explains a lot of the heritable risk, but not all of it. Studies have also implicated immune-regulatory genes outside the HLA region, such as CTLA4 and PTPN22 — both involved in setting the threshold for T-cell activation — and genes in the IL2/IL21 region tied to immune signaling. This overlapping architecture is why alopecia areata often co-occurs with conditions like thyroid autoimmunity and vitiligo.

What genetic risk does and does not tell you

Carrying higher-risk HLA variants does not mean you have or will develop alopecia areata. Autoimmune conditions emerge from a mix of genetics, immune history, and environmental triggers, and most people with risk variants never develop the condition. Genetic information is context, not a diagnosis. If you notice unexplained hair loss, a dermatologist can evaluate it and discuss options — a clinical path a genetic result does not replace.

Pathway-level genetic insight

Genetic self-knowledge is most useful as background for an informed conversation. While the genetics of alopecia areata center on the HLA region, understanding your broader genetic baseline can add context to how you think about immune and inflammatory biology. The Precision Peptide Genetic Test analyzes 14 pathways, 49 peptides, 150+ genetic insights across pathways that shape your individual biology. It is educational, not diagnostic: it tells you about your biology, not what to put in your body, and it does not diagnose, treat, or manage any condition. That is the "test before you invest" approach.

Frequently Asked Questions

Is alopecia areata genetic?

Partly. Alopecia areata has a strong genetic component concentrated in the HLA region, which governs immune self-recognition. However, genetics sets predisposition rather than certainty — environmental triggers and immune history also contribute, and most people carrying risk variants never develop the condition.

What is HLA-DQA2?

HLA-DQA2 is a class II gene in the HLA complex that helps encode molecules presenting protein fragments to helper T cells. Variants in and around HLA-DQA2 are associated with higher alopecia areata risk, reflecting how subtle immune-recognition differences can influence autoimmune tendencies.

Can a genetic test diagnose alopecia areata?

No. Alopecia areata is diagnosed clinically by a dermatologist based on examination and sometimes a scalp biopsy. Genetic testing can describe inherited risk factors as educational context, but it does not diagnose, treat, or manage the condition, and it cannot predict whether it will occur.

Do other genes besides HLA affect alopecia areata risk?

Yes. Immune-regulatory genes outside the HLA region, including CTLA4, PTPN22, and the IL2/IL21 region, have been associated with risk. This shared immune architecture helps explain why alopecia areata often co-occurs with other autoimmune conditions such as thyroid disease and vitiligo.

Want to understand the immune and inflammatory pathways in your own genetics? The Precision Peptide Genetic Test offers pathway-level insight into your individual biology as educational context. Explore the Precision Peptide Genetic Test.

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

Disclaimer: 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.