CBL syndrome is a Noonan-like RASopathy with heterogeneous clinical phenotype and predisposition to juvenile myelomonocytic leukemia (JMML). Here we describe two patients with identical germline CBL mutation and clinical and immune-hematological overlapping features with autoimmune lymphoproliferative syndrome (ALPS) and B-cell expansion with NF-κB and T-cell anergy (BENTA) syndrome. Increased immature/transitional B cells can be depicted in CBL syndrome, ALPS, and BENTA. Nonetheless, our patients here described showed peculiar B-cell phenotype due to increased immature/transitional CD34+ B cells. This feature differentiates CBL syndrome from BENTA, pointing toward an abnormal proliferation of B-cell early precursors.
Keywords: ALPS; BENTA; CARD11; CBL; RALD; RASopathies; lymphocytosis; splenomegaly.
Copyright © 2022 Saettini, Coliva, Vendemini, Galbiati, Bugarin, Masetti, Moratto, Chiarini, Guerra, Iascone, Badolato, Cazzaniga, Niemeyer, Flotho and Biondi.