HLA-DQ9

HLA-DQ9 (DQ9) is an HLA-DQ split antigens also recognized by DQ3, and is specific to the HLA-DQB1*0303 gene product.

=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 DBB1*group 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.

=Alleles= DQB1*0303 (DQ9) is assoicated with nasal polyps, gestational diabetes, microscopic polyangiitis (Japanese). Primary linkage is with DRB1*0901-DQB1*0303

=Haplotypes=

DQ9.2
DQA1*0201:DQB1*0303 is associated with type I psoriasis (vulgaris),

DQ9.3
DQA1*0301:DQB1*0303 maybe associated with juvenile diabetes in the orient. (Chinese) Primary linkage of vitiligo is with DQA1*03-DQB1*0303

=References=