FOXI3 encodes a forkhead family transcription factor essential for pharyngeal arch development and craniofacial morphogenesis 1. The protein functions as a pioneer transcription factor regulating multiple developmental processes including otic placode formation, hair follicle stem cell specification, and pharyngeal pouch development 23. FOXI3 is required for pre-placodal ectoderm to respond to inductive signals and form the inner ear, with loss-of-function resulting in absence of otic placodes and associated structures 2. In hair development, FOXI3 controls stem cell specification and activation, with deficiency leading to impaired follicle downgrowth and progressive hair loss 3. The protein genetically interacts with TBX1 in pharyngeal pouch endoderm development, regulating thymus and parathyroid gland formation 4. Pathogenic FOXI3 variants cause craniofacial microsomia and oculo-auriculo-vertebral spectrum disorders, characterized by ear dysplasia, microtia, mandibular hypoplasia, and facial asymmetry 156. These conditions show autosomal dominant inheritance with reduced penetrance or autosomal recessive patterns 1. FOXI3 variants represent the second most frequent genetic cause of craniofacial microsomia, accounting for approximately 1% of all cases and 13% of familial cases 5.