PTPN11 and Noonan syndrome with multiple lentigines: While the majority of reported patients with pathogenic variants in PTPN11 gene are associated with Noonan and multiple lentigines syndromes, which have gain-of-function as a mechanism of molecular pathogenesis [27, 28], only 17 cases were linked MC to LoF variants in the PTPN11 gene [25, 26].