HLA-DQ9 (DQ9) 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 A serotype or serovar is a distinct variation within a species of bacteria or virus or among immune cells of different individuals. These microorganisms, viruses, or cells are classified together based on their surface antigens, allowing the epi ...

within the

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. DQ9 is a

split antigen Split(s) or The Split may refer to: Places * Split, Croatia, the largest coastal city in Croatia * Split Island, Canada, an island in the Hudson Bay * Split Island, Falkland Islands * Split Island, Fiji, better known as Hạfliua Arts, enterta ...

of the DQ3 broad antigen. DQ9 is determined by the antibody recognition of β⁹ and this generally detects the gene product of DQB1 *0303.

Serology

The serotyping efficiency of DQ9 is poor. The recognition of DQB1*0303 by DQ9 and or DQ3 is poorest, DQ2 which recognizes a different DQB1 subgroup recognizes DQB1*0303 as efficiently as DQ3. For this reason DQ9 serotyping is a poor method of typing for transplantation or disease association prediction or study.

DQB1*0303

(DQ9) is associated with nasal polyps,

gestational diabetes Gestational diabetes is a condition in which a woman without diabetes develops high blood sugar levels during pregnancy. Gestational diabetes generally results in few symptoms; however, it increases the risk of pre-eclampsia, depression, and of ...

, microscopic polyangiitis (Japanese). Primary linkage is with DRB1*0901-DQB1*0303

Haplotypes and disease

DQ9.2

DQA1*0201:DQB1*0303 is associated with type I

psoriasis Psoriasis is a long-lasting, noncontagious autoimmune disease characterized by raised areas of abnormal skin. These areas are red, pink, or purple, dry, itchy, and scaly. Psoriasis varies in severity from small, localized patches to complete ...

(vulgaris),

DQ9.3

DQA1*0302:DQB1*0303 maybe associated with juvenile diabetes in the orient. (Chinese) Primary linkage of

vitiligo Vitiligo is a disorder that causes the skin to lose its color. Specific causes are unknown but studies suggest a link to immune system changes. Signs and symptoms The only sign of vitiligo is the presence of pale patchy areas of depigmen ...

is with DQA1*03-DQB1*0303.

References

{{DQ serotypes 9 9