PTPN11 and Noonan syndrome: For example, PTPN11, the variations in PTPN11 are the primary cause of Noonan syndrome with multiple lentigines and Noonan syndrome, which have common skin and facial symptoms, cardiac abnormalities and growth retardation, and hearing loss is considered to be a rare feature in these patients (Qiu et al., 1998; Niemeyer, 2014).