NCIt definition : Human C4B_2 wild-type allele is located in the vicinity of the 6p21.3 alternate reference
locus and is approximately 21 kb in length. This allele, which encodes complement
C4-B protein, plays a role in complement-dependent immune processes. The expression
of this gene is associated with the expression of Chido blood group antigens. Mutation
of the gene is associated with complement component C4B deficiency. Copy number variation
and polymorphisms are associated with increased risk for systemic lupus erythematosus.;