Costello syndrome is characterised by postnatal growth retardation, coarse facies, intellectual deficit, skin anomalies and cardiac abnormalities. The prevalence is unknown, but around 150 cases have been reported in the literature. Dermatological findings include redundant skin on the neck, palms, fingers and soles (with hyperkeratosis of the palms and soles and thickening of the loose skin of the arms and legs), acanthosis nigricans, dark skin, and papillomata. Failure to thrive during the first months of life results in short stature despite normal weight gain in later life. Cardiomyopathy is frequent but other forms of visceral involvement are rare. Mild to moderate intellectual deficit is usual and most patients exhibit a characteristic sociable and friendly personality. Hyperextensiblity of the fingers and foot position defects are frequent. Children are predisposed to the development of tumours, especially rhabdomyosarcomas. The majority of cases are caused by de novo mutations in the ras family oncogene, HRAS (localised to 11p15.5). Diagnosis mainly depends on the clinical picture: papillomata represent the most characteristic manifestation but may arise late in life. The peculiar course of the disease, the typical facies, and the ectodermal involvement with loose and hyperpigmented skin are characteristic enough to allow an early diagnosis. Differential diagnosis should include Noonan syndrome and cardio-facio-cutaneous syndrome. There is no specific treatment for Costello syndrome. Cardiac examinations should be performed to identify heart defects, and physical and occupational therapy are recommended. The prognosis depends on the severity of the cardiomyopathy and on the occurrence of malignant tumours.
Last update: July 2006