Surveillance registry, defined as a post-authorisation observational registry, called the Eu-IGFD {European Increlex® (Mecasermin [rDNA Origin] Injection) Growth Forum Database} which is intended primarily to monitor the safety of Increlex® replacement therapy in children with growth failure and secondly to follow the effectiveness of this treatment. Patients who have already started Increlex® therapy before entering this observational registry may be included in this registry and data will be collected retrospectively.