The Clinical and Molecular Spectrum of Turkish Patients with Syndromic Craniosynostosis: A Single Center Study

Objective: Syndromic craniosynostosis is caused by pathogenic variants in genes regulating suture development. This study aims to investigate clinical and molecular characteristics in syndromic craniosynostosis. Materials and Methods: This retrospective descriptive study included 53 patients from 40 families with syndromic craniosynostosis. Molecular testing was performed in 22 families. Results: The study included Saethre-Chotzen (n=14), Apert (n=12), Crouzon (n=11), Pfeiffer (n=4), Muenke (n=4), and Carpenter (n=1) syndromes, Crouzon syndrome with acanthosis nigricans (n=2), craniosynostosis with dental anomalies (n=2), craniosynostosis type 4 (n=2), and hypochondroplasia with craniosynostosis (n=1). Genetic etiology was identified in 20 families involving six genes: FGFR1 (Pfeiffer), FGFR2 (Apert, Crouzon, Pfeiffer), FGFR3 (Crouzon with acanthosis nigricans, Muenke), TWIST1 (Saethre-Chotzen), ERF (Craniosynostosis type 4), and IL11RA (Craniosynostosis with dental anomaly). Additionally, a FGFR3 variant causing hypochondroplasia was identified in a patient with multisuture synostosis. Familial inheritance was identified in 25%, but not in Apert syndrome. Brachycephaly (28.3%) was the most common cranial abnormality, followed by plagiocephaly (22.6%). Apert syndrome was characterized by frequent cardiac anomalies, cleft palate, developmental delay, and a higher rate of surgical intervention. In contrast, Crouzon, Pfeiffer, Saethre–Chotzen, and Muenke syndromes showed favorable outcomes, although a fatal course was observed in a patient with Crouzon syndrome with acanthosis nigricans. Rare etiologies included ERF-related craniosynostosis with mild craniofacial findings and IL11RA-related craniosynostosis with intrafamilial phenotypic heterogeneity. Conclusion: This study describes clinical features of well-defined syndromes such as Apert, Crouzon, and Pfeiffer; reports craniosynostosis in hypochondroplasia; and documents rare ERF- and IL11RA-related forms, highlighting the importance of combining clinical and molecular diagnostics.