Furthermore, the severity of CM in children was correlated with the inhibition of ADAMTS13 and thus with an increase of abnormal circulating ultra large von Willebrand factor (ULVWF) multimers that cross-link platelets, induce thrombocytopaenia [5] and enhance obstruction of the brain microvasculature [15, 16]. The gene discussed is ADAMTS13; the disease is cutaneous mastocytosis.