Growth hormone replacement therapy in Costello syndrome

• In patients with CS linear growth is slow and results in short stature.
• Growth hormone deficiency has been reported in up to 40% of cases.
• Given the risk of malignancy and myocardiopathy in children with CS, growth hormone replacement treatment is controversial.
• The index patient is a paradigm of successful and safe long-term treatment with growth hormone.

Costello syndrome (CS) is considered an overgrowth disorder given the macrosomia that is present at birth. However, shortly after birth the weight drops dramatically and the patients are usually referred for failure to thrive. Subsequently, affected patients develop the distinctive coarse facial appearance and are at risk for cardiac anomalies and solid tumor malignancies. Various endocrine disorders, although not very often, have been reported in patients with CS, including growth hormone deficiency, hypoglycemia, ACTH deficiency, cryptorchidism and hypothyroidism. We report a case of Costello syndrome with hypothyroidism, cryptorchidism and growth hormone deficiency and we evaluate the long-term safety and efficacy of growth hormone replacement therapy. The index patient is a paradigm of successful and safe treatment with growth hormone for almost 7 years. Since patients with CS are at increased risk for cardiac myopathy and tumor development they deserve close monitoring during treatment.