This clinical trial focuses on children with Prader-Willi Syndrome (PWS), a genetic condition that affects growth, metabolism, and development. The study involves a treatment using a nasal spray solution called Otwillo, which contains the active substance oxytocin. Oxytocin is a hormone that plays a role in social bonding and behavior. The purpose of the study is to confirm the long-term safety of this treatment in children who have previously participated in the OTBB3 study.

The study will follow children with Prader-Willi Syndrome up to the age of four. It will compare those who have been treated with Otwillo in the previous OTBB3 study to those who have not received this treatment. The study will monitor the occurrence of any adverse events, which are unwanted effects that may happen during the study, as well as any serious adverse events. It will also track the development of other health conditions that often occur alongside Prader-Willi Syndrome, known as comorbidities.

Throughout the study, information will be collected on any medications, surgeries, or rehabilitation therapies the children may undergo. This will include details such as the type of treatment, the age at which it started and stopped, and how often it was given. The study aims to provide valuable insights into the long-term effects and safety of using oxytocin nasal spray in managing Prader-Willi Syndrome in young children.