WNT4 is a signaling ligand that activates both canonical and non-canonical Wnt pathways, playing crucial roles in embryonic development and adult tissue homeostasis. In development, WNT4 is essential for nephron formation, where it drives the mesenchyme-to-epithelium transition during kidney development 1. It serves as a critical regulator of female reproductive development, controlling ovarian differentiation and Müllerian duct formation while antagonizing testosterone production 2. Beyond development, WNT4 maintains diverse physiological functions in adults. Non-canonical WNT4 signaling drives metabolic maturation of pancreatic β-cells, enabling glucose-stimulated insulin secretion 3. The protein promotes osteogenic differentiation of bone marrow mesenchymal stem cells through activation of the β-catenin pathway 4. However, WNT4 also contributes to pathological processes, including cardiac fibrosis following myocardial infarction through β-catenin/NF-κB signaling activation 5. Clinical significance is evident in reproductive health, where WNT4 mutations cause Müllerian aplasia with hyperandrogenism 2, and altered expression associates with endometrial cancer 6. Large-scale genetic studies confirm WNT4's importance across multiple female reproductive health conditions 7, highlighting its therapeutic potential for developmental disorders, metabolic diseases, and reproductive health conditions.