1. ¹Department of Pediatrics, Instituto da Criança, HC, University of São Paulo, Av. Dr. Enéas Carvalho de Aguiar, 647, Cerqueira César, 05403-900 São Paulo, SP, Brazil
2. ²Department of Cardiology, Heart Institute (InCor), São Paulo, Brazil

Correspondence: Débora Romeo Bertola, Department of Pediatrics, Instituto da Criança, HC, University of São Paulo, Av. Dr. Enéas Carvalho de Aguiar, 647, Cerqueira César, 05403-900 São Paulo, SP, Brazil. E-mail: deborarb@icr.hcnet.usp.br

Received 13 November 2006; Accepted 29 March 2007; Published online 28 April 2007.

Abstract

Costello syndrome is an autosomal dominant disorder comprising growth deficiency, mental retardation, curly hair, coarse facial features, nasal papillomata, low-set ears with large lobes, cardiac anomalies, redundant skin in palms and soles with prominent creases, dark skin, and propensity to certain solid tumors. HRAS mutations have been implicated in approximately 85% of the affected cases. The clinical overlap among Costello, Noonan, and cardiofaciocutaneous syndromes is now better understood given their common molecular background, such that all these syndromes constitute a class of disorders caused by deregulated RAS-MAPK signaling. We report on a novel KRAS gene mutation in a patient presenting the clinical features typical of Costello syndrome and the additional findings seen in Noonan syndrome. This description emphasizes that a subset of patients with Costello syndrome could harbor mutations in other genes involved in the RAS-MAPK signaling.