What is Prader-Willi syndrome, which triggers insatiable hunger?

Prader-Willi syndrome is a rare genetic condition affecting a child's metabolism, which triggers insatiable hunger. This can lead to severe obesity if excessive eating isn’t controlled. The symptoms include behavioural challenges, such as emotional outbursts and physical aggression, lack of sexual development & learning difficulties. The multisystem disorder affects one in 10,000 to 30,000 people.