DNAJC4 is a heat shock protein family member (Hsp40) that functions as a molecular chaperone involved in protein folding and response to cellular stress. As an Hsp40 chaperone protein, DNAJC4 contains the characteristic J domain found in DnaJ proteins and possesses a membrane-spanning region 1, enabling its role in unfolded protein binding and protein folding processes. The protein is expressed across multiple tissues and shows temperature-dependent expression patterns during fever and systemic inflammation 2. DNAJC4 has emerged as a significant risk factor across multiple disease contexts. Genetic fine-mapping studies identified DNAJC4 as a likely causal gene for bipolar disorder susceptibility, with convergent evidence supporting its role in neurotransmission and neurodevelopment 3. Sex-specific genetic variants in DNAJC4 are associated with coronary endothelial dysfunction, suggesting gender-related differences in atherosclerosis development 4. The gene was identified as a hub gene shared between COVID-19 and benign prostatic hyperplasia pathogenesis 5. In reproductive physiology, DNAJC4 expression is substantially reduced following glucocorticoid stress, with implications for male fertility 6. Additionally, DNAJC4 was identified as a key mitochondrial-related gene in osteoporosis-affected bone mesenchymal stem cells, linking it to impaired mitochondrial function and osteogenic differentiation 7. These findings indicate DNAJC4 participates in HSP40-mediated protein quality control across multiple physiological systems.