Patients lacking diagnostic criteria for myelodysplastic syndrome, but who show an unexplained persistent cytopaenia are classified as patients suffering from idiopathic cytopaenia of undetermined significance (ICUS). A fraction of these patients carry somatic mutations in genes which are also mutated in myeloid neoplasms. The significance of these mutations in ICUS patients is not well known and only few research papers have tried to correlate them with clinical outcome. ICUS patients carrying somatic mutations seem to have a higher progression rate to myeloid malignancies compared to unmutated patients. Some mutation profiles also show lower overall survival, similar to patients with (low-risk) myelodysplastic syndrome. Therefore, it seems useful to screen for somatic mutations in cytopaenic patients. The goal of this paper is to review recent literature regarding the significance of somatic mutations in cytopaenic patients and propose a screening protocol by evaluating a test protocol at the AZ Sint-Jan hospital Brugge-Oostende.

(BELG J HEMATOL 2019;10(6):231–40)