Costello Syndrome Associated With Somatic Mosaicism of Rare p.Gly13Asp HRAS Variant: Expanding the Phenotypic Spectrum
Costello syndrome (CS) is a rare RASopathy, mostly caused by de novo heterozygous pathogenic variants in the HRAS gene. Over 80% of cases involve the germline p.Gly12Ser variant, resulting in a fairly uniform phenotype of neuro‐cardio‐facio‐cutaneous involvement with an increased risk of malignancy. Consequences of oth...