PTPN11 and Noonan syndrome: Paternal bias, the mutation detected in patients was more likely to be found in the paternal chromosome, has been reported in several monogenetic disorders such as Apert syndrome (caused by FGFR2 gene variants), Noonan syndrome (caused by PTPN11 gene variants), and achondroplasia (caused by FGFR3 gene variants) [10, 11].