NCIt definition : Human C4A wild-type allele is located in the vicinity of 6p21.3 and is approximately
21 kb in length. This allele, which encodes complement C4-A protein, is involved in
the innate immune response. The expression of this gene is associated with the expression
of Rodgers blood group antigens. Mutation of the gene is associated with complement
component C4A deficiency. Copy number variation and polymorphisms are associated with
increased risk for systemic lupus erythematosus.;