IL12B Gene

The IL12B gene (IL12B stands for interleukin-12B) is a protein-coding gene located on chromosome 5q33.3. The IL12B gene encodes a subunit of interleukin 12, a cytokine that acts on T cells and natural killer cells and induces a wide range of biological activities.

Interleukin-12 is a disulfide-linked heterodimer composed of the 40 kD cytokine receptor-like subunit encoded by this gene and a 35 kD subunit encoded by IL12A. Interleukin-12 is expressed by activated macrophages, which serve as an essential trigger for Th1 cell development. This cytokine has been shown to be important for maintaining sufficient numbers of memory/effector Th1 cells to mediate long-term protection against an intracellular pathogen.

Diseases associated with IL12B include:

• Immunodeficiency 29
• Takayasu arteritis

Overexpression of this gene has been observed in the central nervous system of patients with multiple sclerosis (MS), suggesting a role for this cytokine in the pathogenesis of the disease (Huang J et al. 2016). Polymorphisms of this gene have been associated with alopecia areata. (Tabatabaei-Panah PS et al 2020).

The promoter polymorphism of this gene has been associated with the severity of atopic and non-atopic asthma in children.

1. Al-Muhsen S et al (2008) The genetic heterogeneity of mendelian susceptibility to mycobacterial diseases. J Allergy Clin Immun 122: 1043-1051.
2. Altare F et al (1998) Inherited interleukin 12 deficiency in a child with bacille Calmette-Guerin and Salmonella enteritidis disseminated infection. J Clin Invest 102: 2035-2040.
3. Huang J et al (2016) Meta-analysis of the IL23R and IL12B polymorphisms in multiple sclerosis. Int J Neurosci 126:205-212.
4. Picard C et al (2002) Inherited interleukin-12 deficiency: IL12B genotype and clinical phenotype of 13 patients from six kindreds. Am J Hum Genet 70: 336-348.
5. Randolph AG et al (2004) The IL12B gene is associated with asthma. Am J Hum Genet 75:709-715.
6. Tabatabaei-Panah PS et al (2020) IL12B and IL23R polymorphisms are associated with alopecia areata. Genes Immun 21:203-210.