FCGR3A Gene

FCGR3A (FCGR3A stands for "Fc Gamma Receptor IIIa") is a protein-coding gene. The gene encodes a receptor for the Fc portion of immunoglobulin G and is involved in the removal of antigen-antibody complexes from the circulation as well as other responses, including antibody-dependent cellular-mediated cytotoxicity and antibody-dependent enhancement of viral infections. Fc gamma receptor IIIa, encoded by this gene, is expressed on NK cells as an integral membrane glycoprotein. It is anchored by a transmembrane peptide.

Mutations in the FCGR3A gene are associated withimmunodeficiency 20. Clinically, this mutation is associated with susceptibilities to recurrent viral infections(herpes zoster), systemic lupus erythematosus of sarcoidosis (Typiak MJ et al. 2014), and alloimmune neonatal neutropenia. An important paralog of this gene is FCGR3B

The FCGR3A gene is very similar to another nearby gene (FCGR3B) on chromosome 1.

Associated signaling pathways include regulation of actin dynamics for phagocytic cup formation and immunoregulatory interactions between a lymphoid and a non-lymphoid cell. Polymorphisms in the FCGR3A gene lead to a better response to tocilizumab and rituximab linked (Jiménez Morales A et al. 2019).

The FCGR3A V158F polymorphism is associated with CBD (chronic berylliosis, J63.2) and alters lung function in this disease CBD (Liu B et al. 2019).

1. de Vries et al.(1996) Identification of an unusual Fc-gamma receptor IIIa (CD16) on natural killer cells in a patient with recurrent infections. Blood 88: 3022-3027.
2. Grier JT et al (2012) Human immunodeficiency-causing mutation defines CD16 in spontaneous NK cell cytotoxicity. J Clin Invest 122: 3769-3780.
3. Jawahar S et al (1996) Natural killer (NK) cell deficiency associated with an epitope-deficient Fc receptor IIIA (CD16-II). Clin Exp Immun 103: 408-413.
4. Jiménez Morales A et al (2019) FCGR2A/FCGR3A Gene Polymorphisms and Clinical Variables as Predictors of Response to Tocilizumab and Rituximab in Patients With Rheumatoid Arthritis. J Clin Pharmacol 59: 517-531.
5. Liu B et al (2019) Polymorphism of FCGR3A gene in chronic beryllium disease. Genes Immun 20: 493-499.