NCIt definition : Human C4B wild-type allele is located in the vicinity of 6p21.3 and is approximately
21 kb in length. This allele, which encodes complement C4-B protein, plays a role
in both host defense and inflammation. 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.;