The role of FAT family cadherins in craniofacial development: A scoping review.

To map the existing evidence on the role of FAT family cadherins in craniofacial development, identify knowledge gaps, and inform future research directions in this field. Electronic searches were conducted in PubMed, Embase, Scopus, Web of Science Core Collection, and ProQuest Dissertations & Theses Global from their inception to January 2026, complemented by manual searches. Studies investigating FAT family cadherins in craniofacial development were included without restrictions on language or publication year. Search strategy and eligibility criteria were pre-determined based on the population, concept and context framework of the Joanna Briggs Institute. Eligible studies included case reports and original studies encompassing bioinformatics analyses, in vitro experiments, animal studies, and human genetic studies. Twenty-one studies were included, encompassing craniofacial bone formation, cranial suture development, upper lip and palate formation, and tooth development. Among the FAT family members, FAT4 was the most frequently studied (n = 12), followed by FAT1 (n = 7). None of the included studies investigated the role of FAT2 in craniofacial development. These cadherins exhibit prominent, stage-specific expression patterns during craniofacial morphogenesis, including the mesenchyme of the medial nasal processes, zygomatic-maxillary suture, and alveolar bone. Six case reports described four congenital syndromes that present with craniofacial abnormalities. The available evidence indicates that FAT family cadherins are substantially involved in craniofacial morphogenesis. However, important research gaps remain, particularly regarding their cooperative functions and precise spatiotemporal roles during craniofacial development, critical for understanding craniofacial anomalies. This review was registered at the Open Science Framework database (https://osf.io/wcxrj).