Suspected SCALP syndrome (sebaceous nevus, CNS malformations, aplasia cutis congenita, limbal dermoid, and pigmented nevus) and the spectrum of mosaic RASopathies: ophthalmic and systemic manifestations in a paediatric cohort

PURPOSE: To describe the clinical spectrum of the ophthalmic and systemic manifestations in children suspected as having SCALP (Sebaceous Nevus, CNS Malformations, Aplasia Cutis Congenita, Limbal Dermoid, and Pigmented Nevus) syndrome. METHODS: We reviewed the medical records of 13 children suspected to have SCALP syndrome between 1 January 2016 and 31 March 2025. Their demographic details and clinical findings were analyzed. RESULTS: Median age at presentation was 1.2 years (range: 5 days to 10 years). Of the 13 patients, 6 (46.2%) were aged ≤ 1 year. The cohort comprised 9 males and 4 females. One patient was born to consanguineous parents. Ocular involvement was bilateral in 6 patients and unilateral in 7. Among the cohort, two children had the complete SCALP phenotype, three presented with partial features, and eight had features of probable mosaic RASopathy. The most consistent clinical findings were limbal dermoids, which were present in all cases except one. Twelve children had scalp findings, with four having aplasia cutis and eight having nevus psiloliparus. Additional ocular features included dermolipomas, upper eyelid coloboma, ptosis, and limbal stem cell deficiency. Systemic manifestations observed included sebaceous nevi, developmental delay, epilepsy with cortical dysplasia. CONCLUSION: SCALP syndrome is a rare neurocutaneous disorder with consistent oculocutaneous features and variable neurological involvement. Early recognition and multidisciplinary care are essential. Developing structured diagnostic criteria and exploring genotypic-phenotypic links would be critical to improving outcomes. SCALP syndrome is best regarded as lying within the spectrum of mosaic RASopathies; in the absence of lesional molecular testing, the diagnosis in individual cases should be considered provisional, with aplasia cutis congenita serving as the key clinical discriminator.