The DR locus of the class II HLA region is unique. Compared to the other classical class II HLA molecules, HLA-DQ and HLA-DP, each of which has a single, polymorphic locus encoding for the alpha and beta chains, the HLA-DR molecule is comprised of an essentially monomorphic alpha chain, and multiple, polymorphic loci that encode for the beta chain. Additionally, there is variability in the number of loci encoding for the beta chains, with either one or two HLA-DRB loci per chromosome. This genetic complexity can lead to challenges in typing HLA-DR for clinical purposes.

In this webinar Dr. Nicholas Brown will discuss the genetic structure of HLA-DR, and discuss how the complexity can be managed.

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