Before and after - Nutritional transformation of dysmorphism in a case of Costello syndrome

Costello syndrome is a type of RASopathy mapped to HRAS gene in chromosome 11, characterized by prenatal overgrowth, postnatal failure to thrive, classic facial gestalt and multisystem involvement including cardiomyopathy and intellectual disability. We present a 7 months old child with severe failure to thrive whose “subtle” facial dysmorphism at the time eluded clinical recognition of the syndrome. It was only with optimization of his nutritional status that dysmorphic features became more apparent, which affirmed the molecular diagnosis of Costello syndrome from exome sequencing. The case illustrated how drastic failure to thrive can be in Costello syndrome, and how nutritional status can transform dysmorphic features in a child. It also highlights the importance of serial dysmorphic evaluation in difficult cases.