Beta-defensin 109B (DEFB109B)

Beta-defensin 109B (DEFB109B) is annotated as a member of the human β-defensin family, a group of small, evolutionarily ancient, cationic antimicrobial peptides known for broad-spectrum activity against bacteria, fungi, and viruses, and important roles in innate immunity[1][2][3]. However, DEFB109B is currently classified as a **pseudogene**, not producing a functional protein product in humans[7]. The gene is predicted based on genomic sequence similarity to other β-defensins but is not known to encode an active protein; it is listed as "defensin beta 109 pseudogene 1B" and has previous aliases and annotations reflecting this nonfunctional status[7]. As a pseudogene, DEFB109B is not a therapeutic target, does not have known biological or disease roles, and is not a biomarker or drug-interacting molecule. **Key distinction:** Although β-defensins generally are antimicrobial peptides classified under the "defensin" family and participate in immune defense—including cell chemotaxis and epithelial barrier functions—DEFB109B itself is not a functional gene but a predicted pseudogene[7]. Classically, functional β-defensins interact with microbial membranes to disrupt pathogens and can signal via chemokine receptors such as CCR6; these properties do not apply to DEFB109B due to the absence of protein product[2][3][7]. **Conclusion:** DEFB109B is a non-functional pseudogene with no current evidence for protein coding or biological activity and should not be considered a molecular therapeutic target[7].

Other names

Beta-defensin 109BDEFB109BDEFB109P1BDEFB-109HBD9Defensin beta 109BDEF109P1Bbeta-defensin 109Bdefensin beta 109 pseudogene 1Bdefensin, beta 9 pseudogeneputative beta-defensin 109B