Table 1.

Primary immunodeficiencies: antibody deficiencies

Disorder	Gene (if known)	IgG replacement indicated?
Agammaglobulinemia
X-linked agammaglobulinemia	Btk	Yes
μ heavy chain deficiency	IGHM	Yes
Igα deficiency	CD79A	Yes
Igβ deficiency	CD79B	Yes
B-cell linker protein	BLNK	Yes
Common variable immune deficiency
Immune co-stimulator protein	ICOS	Yes
CD19 deficiency	CD19	Yes
CD20 deficiency	CD20	Yes
TACI deficiency	TNFRSF13B	Yes
BAFF receptor deficiency	TNFRSF13C	Yes
CVID	Unknown	Yes
Other antibody deficiencies
Selective IgA deficiency	Unknown	No
IgG subclass deficiency	Unknown	If recurrent infections
Specific antibody deficiency	Unknown
Transient hypogammaglobulinemia of infancy	Unknown
Other PIDD with antibody deficiency
HyperIgM syndrome X-linked	CD40L	Yes
Autosomal recessive	AID, UNG	Yes
Severe combined immune deficiency	Various	Yes
Wiskott–Aldrich syndrome	WASP	Yes
Ataxia-telangiectasia syndrome	ATM	Yes
Reticular dysgenesis	AK2	Yes
DiGeorge syndrome	22q11.2/10p13 deletion	Only for patients with low IgG

Note: Data based on IUIS classification of primary immune deficiencies.¹

Abbreviations: IgG, immunoglobulin G; Btk, Bruton’s tyrosine kinase; TACI, transmembrane activator and calcium-modulating cyclophilin ligand interactor; TNFRSF, tumor necrosis factor receptor super family; BAFF, B-cell activating factor; CVID, common variable immune deficiency; CD40L, CD40 ligand; AID, activating inducing cytidine deaminase; UNG, uracil DNA glycosylase; WASP, Wiskott–Aldrich syndrome protein; ATM, ataxia-telangiectasia mutated; AK2, adenylate kinase 2.