Growth Hormone Treatment for Achondroplasia.

Achondroplasia (ACH) is the most common form of skeletal dysplasia causing rhizomelic, short-limb short stature. Short- and long-term clinical trials have been conducted with rhGH, with similar results across these studies. At supraphysiological dose of GH, height gain of 1-1.5 SDS on the population curve was observed during the first 1-3 years, which was then followed by a smaller increase in growth rate persisting for 5-6 years. These studies led to the approval of rhGH for ACH in Japan where rhGH has been used for 20 years at 0.05 mg/kg/day. Although the available data are still limited, compared to untreated controls, total gain in adult height has been greater in males than in females, reported at 3.5-8.0 cm and 2.8-4.2 cm, respectively. Serious adverse events have been rare although some were potentially life-threatening and need careful monitoring. These results should serve as a comparator for novel emerging treatments for ACH.