Agammaglobulinemia

A primary immunodeficiency disorder - low/absent serum antibodies and low/absent circulating B cells.

Most congenital cases are X-linked form (XLA). Other patients have autosomal recessive form (ARA).

Some cases due to hypomorph mutation that hampers but not completely abolish B cell development and function.

XLA = defect in Btk, involved in downstream signalling of pre-BCR or BCR

ARA = defect in BCR or downstream signalling molecules (BLNK, an adaptor protein)

Treatment
Ig injections, either monthly intravenous (IVIG) or weekly subcutaneous (SCIg). IVIG contains polyclonal IgG from pooled human plasma donations.