Definition:

CBL is a ubiquitously expressed E3 ubiquitin ligase that negatively regulates intracellular signalling downstream of receptor tyrosine kinases. Missense CBL mutations cause impaired growth, developmental delay, and cryptorchidism resembling Noonan syndrome. In addition, patients have distinctive facial features, cardiovascular malformation, cerebellar vermis hypoplasia, and predisposition to juvenile myelomonocytic leukaemia.