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HLA-DQA1 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

HLA-DQA1 gene

The HLA-DQA1 gene is essential for immune system function, helping the body identify foreign pathogens and triggering appropriate immune responses.

Overview

The HLA-DQA1 gene is part of the human leukocyte antigen (HLA) complex, which helps the immune system distinguish the body's own proteins from those of foreign invaders like viruses and bacteria. It belongs to the MHC class II group, which provides instructions for proteins that display foreign peptides to the immune system.

The protein produced by HLA-DQA1 binds to the protein produced by the HLA-DQB1 gene to form an antigen-binding DQαβ heterodimer. This complex is responsible for triggering the body's immune response. There are hundreds of different alleles of this gene, allowing the immune system to recognize a vast array of potential threats.

Health Conditions Related to Genetic Changes

Celiac disease

Two specific HLA haplotypes increase the risk of celiac disease by predisposing the immune system to react inappropriately to gluten:

  • DQ2: Formed by HLA-DQA1 variants (HLA-DQA1*05:01 or HLA-DQA1*05:05) and HLA-DQB1 variants (HLA-DQB1*02:01 or HLA-DQB1*02:02).
  • DQ8: Formed by HLA-DQA1 variants (HLA-DQA1*03:01 or HLA-DQA1*03:02) and the HLA-DQB1*03:02 variant.

Type 1 diabetes

Risk for type 1 diabetes is strongly influenced by specific HLA haplotypes involving HLA-DQA1, HLA-DQB1, and HLA-DRB1. The highest risk occurs in individuals who possess one copy of the DR3 haplotype (DRB1*03:01-DQA1*05:01-DQB1*02) and one copy of the DR4 haplotype (DRB1*04:01/02/04/05/08-DQA1*03:01-DQB1*02).

Other disorders

Variations in HLA-DQA1 can influence susceptibility to various conditions:

  • Infections: Certain variants can affect the risk or severity of infections such as hepatitis B and leprosy.
  • Drug-induced liver damage: The HLA-DQA1*02:01 variant increases the risk of liver damage in women with advanced breast cancer treated with the drug lapatinib.
  • Autoimmune disorders: Various normal variations are associated with an increased risk of autoimmune conditions, where the immune system attacks the body's own tissues.

Frequently Asked Questions

Yes, variations in the HLA-DQA1 gene can influence susceptibility to other conditions. For instance, certain variants have been linked to an altered risk or severity of various infections, such as hepatitis B and leprosy. Additionally, the HLA-DQA1*02:01 variant has been associated with an increased risk of drug-induced liver damage in specific populations, particularly in women with advanced liver disease.
Genetic testing for HLA-DQA1 variants typically involves a blood or saliva sample. The test identifies specific alleles or haplotypes (combinations of HLA genes) that are known to be associated with certain conditions. For example, it can determine if you carry the DQ2 or DQ8 haplotypes linked to celiac disease. This information indicates your genetic risk or predisposition, but it is not a diagnostic test for the active disease itself.
No, having specific HLA-DQA1 variants, such as those forming DQ2 or DQ8 haplotypes for celiac disease or certain DR3/DR4 combinations for type 1 diabetes, significantly increases your genetic predisposition but does not guarantee you will develop the condition. These genes are necessary but not sufficient; other genetic and environmental factors also play a crucial role in whether these conditions manifest.
Knowing your HLA-DQA1 status can be very useful for guiding screening and early intervention strategies. For celiac disease, a negative test for DQ2/DQ8 effectively rules out the condition, avoiding unnecessary biopsies. For those with positive results, it can prompt earlier monitoring or dietary considerations. For type 1 diabetes, it helps assess risk for family members and may inform participation in prevention trials. It can also be relevant for understanding susceptibility to certain infections or drug reactions.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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