HLA-DQ6 (DQ6) is a

human leukocyte antigen The human leukocyte antigen (HLA) system or complex is a complex of genes on chromosome 6 in humans which encode cell-surface proteins responsible for the regulation of the immune system. The HLA system is also known as the human version of th ...

serotype within

HLA-DQ HLA-DQ (DQ) is a cell surface receptor protein found on antigen-presenting cells. It is an αβ heterodimer of type MHC class II. The α and β chains are encoded by two loci, HLA-DQA1 and HLA-DQB1, that are adjacent to each other on chromos ...

(DQ) serotype group. The serotype is determined by the antibody recognition of β⁶ subset of DQ β-chains. The β-chain of DQ

isoform A protein isoform, or "protein variant", is a member of a set of highly similar proteins that originate from a single gene or gene family and are the result of genetic differences. While many perform the same or similar biological roles, some iso ...

s are encoded by HLA-DQB1 locus and DQ6 are encoded by the HLA-DQB1 allele group. This group currently contains many common alleles, DQB1 is the most common. HLA-DQ6 and DQB1 are almost synonymous in meaning. DQ6 β-chains combine with α-chains, encoded by genetically linked

HLA-DQA1 Major histocompatibility complex, class II, DQ alpha 1, also known as HLA-DQA1, is a human gene present on short arm of chromosome 6 (6p21.3) and also denotes the genetic locus which contains this gene. The protein encoded by this gene is one of tw ...

alleles, to form the

cis Cis or cis- may refer to: Places * Cis, Trentino, in Italy * In Poland: ** Cis, Świętokrzyskie Voivodeship, south-central ** Cis, Warmian-Masurian Voivodeship, north Math, science and biology * cis (mathematics) (cis(''θ'')), a trigonome ...

haplotype A haplotype ( haploid genotype) is a group of alleles in an organism that are inherited together from a single parent. Many organisms contain genetic material ( DNA) which is inherited from two parents. Normally these organisms have their DNA or ...

isoforms. For DQ6, however, cis-isoform pairing only occurs with DQ1 α-chains. There are many haplotypes of DQ6.

Serology

Alleles

DQB1*0601

DQB1*0601 is generally linked to DQA1*0103 as

6.1 Surround sound is a technique for enriching the fidelity and depth of Sound recording and reproduction, sound reproduction by using multiple audio channels from speaker (electronics), speakers that surround the listener (surround channels). It ...

haplotype. This haplotype is more common in Japan and other parts of East Asia.

DQB1*0602

DQB1*0602 is commonly linked to DQA1*0102 to form 6.2 haplotype. DQ6.2 and is common from Central Asia into Western Europe, *0602 is also linked to DQA1*0103 in parts of Asia.

DQB1*0603

DQB1*0603 is commonly linked to DQA1*0103 as 6.3 and is common from Central Asia into Western Europe, *0603 is also linked to DQA1*0102 in parts of Asia. In Europe it is most common in the Netherlands.

DQB1*0604

DQB1*0604 is found at higher frequencies in parts Africa and Asia and is linked almost exclusively to DQA1*0102 as 6.4. This haplotype is found at its highest Eurasian frequencies in Japan.

DQB1*0609

DQB1*0609 is found in Africa and proximal regions of Eurasia.

Haplotypes and disease

Susceptibility to '' Leptospirosis'' infection was found associated with undifferentiated DQ6. Whereas DQ6 was protective against death (or need for liver transplantion) in

primary sclerosing cholangitis Primary sclerosing cholangitis (PSC) is a long-term progressive disease of the liver and gallbladder characterized by inflammation and scarring of the bile ducts, which normally allow bile to drain from the gallbladder. Affected individuals may ha ...

DQ6.1

DQA1*0103:DQB1*0601 (DQ6.1) is found at increased frequencies in Asia and is almost absent in Western Europe. It confers protection from

narcolepsy Narcolepsy is a long-term neurological disorder that involves a decreased ability to regulate sleep–wake cycles. Symptoms often include periods of excessive daytime sleepiness and brief involuntary sleep episodes. About 70% of those affect ...

juvenile diabetes Type 1 diabetes (T1D), formerly known as juvenile diabetes, is an autoimmune disease that originates when cells that make insulin (beta cells) are destroyed by the immune system. Insulin is a hormone required for the cells to use blood sugar f ...

, Vogt-Koyanagi-Harada (VKH) syndrome, pemphigus vulgaris,

multiple sclerosis Multiple (cerebral) sclerosis (MS), also known as encephalomyelitis disseminata or disseminated sclerosis, is the most common demyelinating disease, in which the insulating covers of nerve cells in the brain and spinal cord are damaged. This d ...

, myasthenia gravis.

DQ6.2

DQ6.2 (DQA1 : DQB1) is commonly linked to DR15 and as such is part of the

HLA B7-DR15-DQ6 HLA B7-DR15-DQ6 is a multigene haplotype that covers a majority of the human major histocompatibility complex on chromosome 6. A multigene haplotype is set of inherited alleles covering several genes, or gene-alleles, common multigene haplotyp ...

haplotype. This haplotype is considered to be the longest multigene haplotype known within the human genome as it covers over 4.7 million nucleotides. The DR15-DQ6.2 haplotype is the most common DR-DQ haplotype in Europe, and approximately 30% of Americans carry at least DQ6.2. The haplotype is even more common in Central Asia.

DQ6.2 associations with disease

For '' myasthenia gravis'', recognition α34-49 of AChR increased with DQ6.2. DQA1 increases risk

cervical cancer Cervical cancer is a cancer arising from the cervix. It is due to the abnormal growth of cells that have the ability to invade or spread to other parts of the body. Early on, typically no symptoms are seen. Later symptoms may include abnormal ...

. In

DQA1 was the most frequent allele and DQB1 increased significantly in the MS patients.

Protective effects of DQ6.2

In '' primary biliary cirrhosis'' DQ6.2 appears to have a negative association with disease. DQ6.2 also appears to have a protective effect in

. DQ6.2 is also protective against infantile spasms in mestizos.

DQ6.3

DQ6.3 (DQA1 : DQB1) is found in northcentral Europe at moderate frequencies, it is a protective against many autoimmune diseases. It also affords some protection to HIV infection.

DQ6.4

DQ6.4 (DQA1 : DQB1) might be associated with thymoma-induced myasthenia gravis.

References

{{DEFAULTSORT:Hla-Dq6 6