What causes Noonan syndrome?

Noonan syndrome is part of a group of related conditions known as RASopathies. Changes in one of several autosomal-dominant genes cause the syndrome. Around half of all cases are caused by mutations in the PTPN11 gene, with a further 10-15% of cases caused by SOS1 gene mutations. Mutations in the RAF1 and RIT1 genes are accounting for around 5% of cases And a further 15-20% of cases present with cause unknown. The PTPN11, SOS1, RAF1, and RIT1 genes are responsible for providing the instructions for making proteins needed for cell division and growth. Mutations in the genes associated with Noonan syndrome cause this protein to be active longer than normal rather than switching on and off in response to cell signals. This then disrupts cell growth regulation and leads to characteristic clinical features of Noonan syndrome. Understand more here, https://fdna.health/syndromes/noonan-syndrome/