KRT34 (keratin 34) is a type II intermediate filament protein involved in epithelial differentiation and structural organization. As a component of the keratin cytoskeleton, KRT34 contributes to hair and skin development as part of the broader keratin family 1. In hair follicles, KRT34 is expressed specifically in the cortex region during fiber development 1. The gene is regulated by Wnt signaling; Frizzled6-mediated Wnt signaling controls KRT34 transcription during nail/claw differentiation, with KRT34 among keratin genes significantly downregulated when Fzd6 is absent 2. KRT34 expression is responsive to cytoskeletal perturbations—F-actin depolymerization triggers rapid upregulation of KRT34 alongside other chromosome 17.2 keratin genes in mesenchymal stem cells, contributing to lineage commitment 3. Reduced KRT34 expression correlates with decreased sperm motility in asthenozoospermic males, suggesting a novel role in sperm function 4. Clinically, KRT34 is overexpressed in premalignant skin keratinocytes with tumorigenic potential 5 and shows differential expression in disease contexts, including COPD-affected bronchial epithelial cells 6 and in intraventricular hemorrhage 7. Population studies indicate KRT34 expression varies between ancestral groups, potentially contributing to differences in bone properties 8.