Myeloproliferative disorder in a patient with RIT1 -associated Noonan syndrome: a case report and literature review

Myeloproliferative disorder (MPD) is a rare complication in individuals with Noonan syndrome (NS) and an RIT1 pathogenic variant; only three cases have previously been reported. However, this condition can be life-threatening. In the present case, a neonate with a massive capillary leak and compromised general condition caused by aggressive MPD, we employed cytoreductive chemotherapy using low-dose cytarabine, which proved to be a valuable therapeutic intervention. For patients presenting with suspected MPD and exhibiting features associated with NS early in life, genetic testing that includes sequencing of RIT1 may confer significant benefits to diagnosis and disease management.