# HLA-DQ6

HLA-DQ6 (DQ6) is a human leukocyte antigen serotype within HLA-DQ (DQ) serotype group. The serotype is determined by the antibody recognition of β$^6$ subset of DQ β-chains. The β-chain of DQ isoforms are encoded by HLA-DQB1 locus and DQ6 are encoded by the HLA-DQB1*06 allele group. This group currently contains many common alleles, DQB1*0602 is the most common. HLA-DQ6 and DQB1*06 are almost synonymous in meaning. DQ6 β-chains combine with α-chains, encoded by genetically linked HLA-DQA1 alleles, to form the cis-haplotype isoforms. For DQ6, however, cis-isoform pairing only occurs with DQ1 α-chains. There are many haplotypes of DQ6.

## Serology

DQ6, DQ1, and DQ5 recognition of some Some DQB1* alleles :
| | DQ6 | DQ1 | DQ5 | N |
| allele | % | % | % | size (N) |
| *0601 | 64 | 23 | | 675 |
| *0602 | 67 | 30 | 1 | 5151 |
| *0603 | 62 | 23 | 2 | 2807 |
| *0604 | 59 | 27 | 2 | 1592 |
| *0605 | 76 | 13 | | 358 |
| *0609 | 48 | 32 | 3 | 149 |

## Alleles

HLA DQB1*0601 frequencies :
| | | freq |
| ref. | Population | (%) |
| | Indig. Australian Cape York | 31.3 |
| | Indig. Australian Kimberly | 30.5 |
| | Nauru | 28.4 |
| | Fiji Viti Levu | 26.3 |
| | India Bombay | 26.3 |
| | Papua New Guinea Lowland | 26.0 |
| | China Guizhou Prov. Miao | 25.9 |
| | Papua New Guinea Madang | 23.1 |
| | Kiribati | 22.6 |
| | Japan | 22.0 |
| | Indonesia Nusa Tenggara | 19.2 |
| | India North Hindus | 18.7 |
| | Japan Hokkaido Wajin | 17.0 |
| | Uttar Pradesh Hindu | 15.1 |
| | PNG Lowland Wosera | 14.1 |
| | Western Samoa & Tokelau | 13.7 |
| | Pakistan Kalash | 13.0 |
| | India Lucknow | 12.9 |
| | China Wuhan | 12.8 |
| | South Korea (4) | 11.4 |
| | PNG Highland | 10.9 |
| | India Delhi | 9.0 |
| | Iran Baloch | 8.0 |
| | Mongolia Khalkha | 5.5 |
| | Lebanon Yuhmur | 4.3 |
| | Tunisia Ghannouch | 4.3 |
| | Poland Wielkopolska | 4.0 |
| | Mexico Mazatecans | 3.5 |
| | Spain E. Andalusia | 2.0 |
| | Italy Central | 1.9 |
| | France South East | 1.6 |
| | England Caucasoid | 1.1 |
| | Ireland South | 0.2 |
| | Italy Sardinia | 0.1 |
| | Brazil Guarani Kaiowa | 0.0 |
| | Cameroon Saa | 0.0 |

### DQB1*0601

DQB1*0601 is generally linked to DQA1*0103 as 6.1 haplotype. This haplotype is more common in Japan and other parts of East Asia.
HLA DQB1*0602 frequencies :
| | | freq |
| ref. | Population | (%) |
| | Spain Pas Valley | 31.5 |
| | Cameroon Saa | 30.8 |
| | Congo Kinshasa Bantu | 30.0 |
| | PNG E. Highlands Goroka | 29.8 |
| | Siberia Ket Lower Yenisey | 29.4 |
| | Spain North Cabuernigo | 28.9 |
| | Russia Arkhangelsk Pomors | 24.7 |
| | Spain North Cantabrian | 24.7 |
| | Ireland South | 19.6 |
| | Belgian (2) | 19.4 |
| | Siberia Kushun Buryat | 18.0 |
| | Finland | 17.1 |
| | Siberia Kets Sulamai Village | 17.0 |
| | Poland Wielkopolska | 16.9 |
| | German Essen | 16.7 |
| | Sp. Basque Arratia Valley | 16.7 |
| | Denmark | 16.6 |
| | France Ceph | 15.7 |
| | Kenya | 14.6 |
| | England Caucasoid | 14.4 |
| | Sweden | 14.1 |
| | France Rennes | 13.8 |
| | Tunisia Matmata Berber | 11.7 |
| | Jordan Amman | 10.7 |
| | Japan Hokkaido Wajin | 10.0 |
| | Saudi A. Guraiat & Hail | 8.4 |
| | Japan Central | 8.2 |
| | Nauru | 8.2 |
| | Georgia Svaneti Svans | 8.1 |
| | France South East | 8.0 |
| | Ethiopia Amhara | 7.7 |
| | Algeria Oran | 7.6 |
| | Slovenia | 7.5 |
| | South Korea (1) | 7.4 |
| | Japan Fukuoka | 6.4 |
| | Pakistan Kalash | 5.8 |
| | China Xinjiang Uygur | 5.4 |
| | Papua New Guinea Lowland | 5.2 |
| | Mongolia Khalkh Ulaanbaatar | 4.9 |
| | Spain Murcia | 4.8 |
| | India Bombay | 4.2 |
| | Japan | 4.0 |
| | Greece (2) | 3.3 |
| | Israel Arabs | 2.3 |
| | Vietnam Hanoi Kinh | 2.0 |
| | Israel Jews | 1.5 |
| | Mongolia Khoton Tarialan | 1.2 |
| | USA Alaska Yupik Natives | 0.8 |
| | Mexico Mixtec Oaxaca | 0.5 |
| | Italy Sardinia pop2 | 0.1 |

### 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.
HLA DQB1*0603 frequencies :
| | | freq |
| ref. | Population | (%) |
| | Georgia Svaneti Svans | 14.4 |
| | France West | 11.0 |
| | Netherlands | 10.6 |
| | German Essen | 9.2 |
| | Czech Republic | 9.0 |
| | Spain Murcia | 8.7 |
| | Slovakia | 8.4 |
| | Denmark | 8.3 |
| | India Lucknow | 8.3 |
| | Jordan Amman | 8.3 |
| | France Rennes | 8.1 |
| | Poland Wielkopolska | 8.0 |
| | Saudi Arabia Guraiat & Hail | 8.0 |
| | Tunisia Jerba Berber | 7.8 |
| | Uganda Muganda Baganda | 7.4 |
| | Spain North Cantabrian | 7.2 |
| | Finland | 7.1 |
| | France South | 6.9 |
| | China Xinjiang Uygur | 6.5 |
| | Russia Northwest Slavic | 6.0 |
| | Ireland Donegal | 5.3 |
| | Greece (3) | 5.2 |
| | Ireland Northern (2) | 4.9 |
| | Italy Rome | 4.0 |
| | CAR Aka Pygmies | 3.6 |
| | Lebanon Kafar Zubian | 3.2 |
| | Sweden | 2.5 |
| | Thailand | 2.1 |
| | China Wuhan | 1.7 |
| | Japan (2) | 1.0 |
| | South Korea (3) | 0.9 |
| | Malaysia | 0.6 |

### 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.
HLA DQB1*0604 frequencies :
| | | freq |
| ref. | Population | (%) |
| | Ethiopia Amhara | 10.7 |
| | Rwanda Kigali Hutu and Tutsi | 10.7 |
| | Ethiopia Oromo | 10.2 |
| | Japan | 8.0 |
| | Saudi Arabia Guraiat & Hail | 8.0 |
| | Iran Yazd Zoroastrians | 6.9 |
| | CAR Aka Pygmies | 6.5 |
| | South Korea (2) | 6.5 |
| | Sweden | 6.1 |
| | Netherlands | 5.6 |
| | Uganda Muganda Baganda | 5.3 |
| | Lebanon Niha el Shouff | 4.9 |
| | Denmark | 4.6 |
| | France Rennes | 4.6 |
| | Israel Gaza Palestinians | 3.9 |
| | China Xinjiang Uygur | 3.8 |
| | Algeria1 | 3.5 |
| | Russia Northwest Slavic | 3.5 |
| | England Caucasoid | 3.1 |
| | German Essen | 2.6 |
| | Czech Republic | 2.4 |
| | Greece | 2.0 |
| | India Delhi | 1.8 |
| | Nauru | 1.5 |
| | Finland | 1.4 |
| | Gambia | 0.7 |

### 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.
HLA DQB1*0609 frequencies :
| | | freq |
| ref. | Population | (%) |
| | Rwanda Kigali Hutu & Tutsi | 5.7 |
| | Kenya | 5.3 |
| | Uganda Muganda Baganda | 5.3 |
| | Congo Kinshasa Bantu | 4.4 |
| | Gambia | 4.4 |
| | Mongolia Tsaatan | 4.2 |
| | South Korea (3) | 3.7 |
| | Cameroon Saa | 3.5 |
| | Slovenia | 3.0 |
| | Tunisia | 3.0 |
| | Zimbabwe Harare Shona | 2.2 |
| | Vietnam Hanoi Kinh | 2.0 |
| | Netherlands | 1.7 |
| | Saudi Arabia Guraiat & Hail | 1.6 |
| | Algeria Oran | 1.5 |
| | Greece (2) | 1.2 |
| | Thailand (2) | 1.2 |
| | Tunisia Matmata Berber | 1.2 |
| | Italy Rome | 1.0 |
| | Spain Granada | 0.7 |
| | Italy Bergamo | 0.6 |
| | Ireland South | 0.2 |
| | China Ürümqi Uygur | 0.0 |
| | USA Alaska Yupik Natives | 0.0 |

### 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.

### 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, juvenile diabetes, Vogt-Koyanagi-Harada (VKH) syndrome, pemphigus vulgaris, multiple sclerosis, myasthenia gravis.

### DQ6.2

DQ6.2 (DQA1*0102 : DQB1*0602) is commonly linked to DR15 and as such is part of the HLA B7-DR15-DQ6 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*0102 increases risk cervical cancer. In multiple sclerosis DQA1*0102 was the most frequent allele and DQB1*0602 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 juvenile diabetes. DQ6.2 is also protective against infantile spasms in mestizos.

### DQ6.3

DQ6.3 (DQA1*0103 : DQB1*0603) 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*0102 : DQB1*0604) might be associated with thymoma-induced myasthenia gravis.