Endocrine Complications of Noonan Syndrome beyond Short Stature

Noonan syndrome (NS) is a diagnosis that is made clinically based on features including typical facies, congenital heart defects, short stature and developmental delay. Approximately 50% of the patients have identified mutations in the PTPN11 gene, and a smaller percentage of mutations have been reported in other genes such as SOS1, RAF1 and RIT1 Despite normal birth length, patients typically reach adult height below normal. Other than growth, endocrine complications of NS are not as commonly reported. These include possible pathology in thyroid function, pubertal development and bone metabolism. Some investigators have looked to see if genetic mutations in these patients could pose a risk for future endocrinopathies. This chapter reviews reports on endocrine dysfunction other than growth in patients with NS. The information is meant to enhance awareness in those providers who care for these patients to the possibility of other existing endocrinopathies. Most importantly, it supports and highlights the endocrinologist's role in the care of patients with NS.