PTPN11 and myelodysplastic syndrome: Indeed, gain-of-function of the PTPN11 gene with a subsequent increase in the reactivity of innate immune cells has been reported in a BD patient with MDS.22 It might be of interest to investigate whether “subkaryotypic” cytogenetic abnormalities or genetic polymorphisms are present in different clinical subsets of BD disease in the absence of MDS.