This class II molecule is a heterodimer consisting of an alpha (DQA) and a beta chain (DQB), both anchored in the membrane.

It plays a central role in the immune system by presenting peptides derived from extracellular proteins.

[5][6] A four-loci genotype study showed that A*01-B*07-DRB1*0701- DQB1*0602 (P = 0.001, OR 41.9) and the A*31-B*51-DRB1*0103- DQB1*0302 (P = 0.012, OR 4.8) are positively associated with autism among Saudi patients.

Celiac1 is a genetic name for DQB1, the HLA DQB1*0201, *0202, and *0302 encode genes that mediate the autoimmune coeliac disease.

Homozygotes of DQB1*0201 have a higher risk of developing the celiac disease, relative to any other genetic locus.