Based on limited published evidence, DEFB129 encodes a beta-defensin with antibacterial activity and protein-binding capacity. DEFB129 was identified as upregulated in the caput epididymidis of fertile men compared to infertile men with nonobstructive azoospermia 1, suggesting a role in male reproductive function. Additionally, DEFB129 gene amplification in the 20p13 chr20 region was detected in tongue cancer recurrence tissue from young adults 2, though its functional significance in cancer pathogenesis remains unclear.