ALX4 is a homeodomain transcription factor essential for craniofacial, skeletal, and ectodermal development. As a Paired-like protein, ALX4 achieves DNA binding specificity through formation of asymmetric dimers on TAAT-NNN-ATTA motifs, with cooperativity between the two proteins required for transcriptional activation 1. ALX4 functions within a regulatory network alongside MSX2, FGFR genes, and other factors to control osteogenic proliferation and bone differentiation in the skull vault 2. The protein negatively regulates the Wnt/β-catenin pathway, influencing ectodermal development 3. Loss-of-function ALX4 variants cause recessive craniosynostosis, frontonasal dysplasia, and parietal foramina, while gain-of-function variants cause dominant frontonasal dysplasia with ectodermal defects 3, 4. Specific variants like p.G369E impair transcriptional activity and associate with genitourinary defects including bladder exstrophy-epispadias complex 5. Beyond development, ALX4 participates in SHH pathway signaling in medulloblastoma pathogenesis 6 and promotes epithelial-mesenchymal transition and invasion in ovarian cancer via SLUG induction 7. These diverse roles reflect ALX4's broad involvement in transcriptional regulation across developmental and oncogenic contexts.