Background: Saethre-Chotzen syndrome (SCS) and Muenke-type mutation (MTM) are complex syndromes with craniosynostosis and skeletal anomalies including syndactyly, carpal and tarsal fusions, and cervical spine abnormalities.
Objective: In this study, we analysed radiographs of the cervical spine, hands and feet of a large patient population with genetically proven SCS and MTM. The aim was to describe the pattern of skeletal anomalies and to determine whether specific features are present that could help differentiate between the two entities.
Materials and methods: Radiographs of 43 patients (23 males, 20 females) with SCS (n=35) or MTM (n=8) were evaluated. The median age was 8 years (range 1 month-36 years). All radiographs were reviewed by two radiologists.
Results: In the hands and feet, a variety of anomalies such as brachyphalangy, clinodactyly, partial syndactyly, partial carpal or tarsal fusion, and cone-shaped epiphyses were noted. Duplicated distal phalanx of the hallux (n=12/35) and triangular deformity of the epiphysis of the distal phalanx of the hallux (n=10/35) were detected in SCS only; calcaneo-cuboid fusion (n=2/35) was detected in MTM only. In the cervical spine, fusion of vertebral bodies and/or the posterior elements occurred only in patients with SCS.
Conclusions: Pathognomonic signs for SCS are the triangular shape of the epiphysis and duplicated distal phalanx of the hallux. Calcaneo-cuboid fusion was detected in MTM only. These signs may be helpful in the differentiation of SCS from MTM.