Phenotypic heterogeneity in Crouzon syndrome: A case of severe intracranial hypertension from isolated temporal squamosal suture synostosis with a de novo FGFR2 p.Cys342Tyr mutation

Crouzon syndrome is generally considered to be hereditary. However, a significant proportion of cases involve de novo mutations. It is characterized by premature closure of the cranial sutures, which leads to craniofacial deformities and/or ocular abnormalities. This report details the case of an 8-month-old female patient who was admitted to our hospital with bilateral exophthalmos. Physical examination indicated Crouzon syndrome. A CT scan of the head revealed bilateral closure of the temporal-parietal sutures, as well as multiple indentations on the medial plates of the temporal and occipital bones. Next-generation sequencing (NGS) detected a novel FGFR2 gene mutation (p.Cys342Tyr), which confirmed the diagnosis. Following a comprehensive evaluation, the patient underwent successful cranial suture reconstruction surgery. Postoperatively, the infant was extubated and transferred to the paediatric intensive care unit (PICU). This report emphasizes the importance of Next-generation sequencing (NGS) in the differential diagnosis of Crouzon syndrome by presenting a unique case involving only temporal-parietal suture closure. Furthermore, it highlights the importance of genetic testing for patients with subtle manifestations of Crouzon syndrome, providing clinical answers and guiding management.