Noonan syndrome and autoimmune hepatitis: patient report and literature review

Abstract Objectives: Noonan syndrome (NS) is a genetic disease characterized by dysregulation in the RAS/MAPK pathway. Affected individuals present peculiar physical features, short stature, and congenital cardiovascular defects. Autoimmune hepatitis is a chronic immunoinflammatory liver disease. Case presentation: A 17-year-old boy with NS due to PTPN11 gene variation and type 1 autoimmune hepatitis (AIH-1; biopsy proven) is described. A literature search on the association between NS and AIH1 showed additional two cases. Conclusions: This report highlights the importance of monitoring patients with NS for signs of autoimmune diseases, mainly liver dysfunction. Precise mechanisms linking NS and AIH-1 remain unclear. Anyway, the dysregulation of the RAS/MAPK pathway may be involved. Periodic monitoring of transaminases and prompt evaluation with liver biopsy should be done to optimize diagnosis and treatment of people with NS.