Novel pathogenic variant in the HRAS gene with lethal outcome and a broad phenotypic spectrum among Polish patients with Costello syndrome

Dermatological manifestations in Costello syndrome: A prospective multicentric study of 31 HRAS-positive variant patients

BACKGROUND

Data on dermatological manifestations of Costello syndrome (CS) remain heterogeneous and lack in validated description.

OBJECTIVES

To describe the dermatological manifestations of CS; compare them with the literature findings; assess those discriminating CS from other RASopathies, including cardiofaciocutaneous syndrome (CFCS) and the main types of Noonan syndrome (NS); and test for dermatological phenotype-genotype correlations.

METHODS

We performed a 10-year, large, prospective, multicentric, collaborative dermatological and genetic study.

RESULTS

Thirty-one patients were enrolled. Hair abnormalities were ubiquitous, including wavy or curly hair and excessive eyebrows, respectively in 68% and 56%. Acral excessive skin (AES), papillomas and keratotic papules (PKP), acanthosis nigricans (AN), palmoplantar hyperkeratosis (PPHK) and 'cobblestone' papillomatous papules of the upper lip (CPPUL), were noted respectively in 84%, 61%, 65%, 55% and 32%. Excessive eyebrows, PKP, AN, CCPUL and AES best differentiated CS from CFCS and NS. Multiple melanocytic naevi (>50) may constitute a new marker of attenuated CS associated with intragenic duplication in HRAS. Oral acitretin may be highly beneficial for therapeutic management of PPHK. No significant dermatological phenotype-genotype correlation was determined between patients with and without HRAS c.34G>A (p.G12S).

CONCLUSIONS AND RELEVANCE

This validated phenotypic characterization of a large number of patients with CS will allow future researchers to make a positive diagnosis, and to differentiate CS from CFCS and NS.

Clinical and molecular characterization of Costello syndrome in unrelated Mexican patients

This study intends to describe for the first time a cohort of Mexican patients with Costello syndrome. The five exons of the HRAS gene were amplified in DNA samples from 13 patients with a clinical suspicion of Costello syndrome. PCR products were sequenced using the Ready Reaction Big Dye Terminator v.3.0 Kit and an ABI PRISM 310 sequencer. Only five patients (38%) showed causal variant in codon 12 of the HRAS gene (four with the p.Gly12Ser and one with the p.Gly12Ala variant). Three patients showed silent polymorphic variants (p.His27His and p.Leu159Leu). Clinical features in patients carrying the causal variant were variable. The alternative diagnosis of cardio-facio-cutaneous syndrome was considered in patients who did not have a causative variant in HRAS.