Familial occurrence of systemic and cutaneous mastocytosis in an adult multicentre series

Mastocytosis represents a group of clonal disorders characterized by abnormal proliferation and infiltration of mast cells in various tissues, particularly skin and haematopoietic organs, ranging from skin-limited diseases to systemic and more aggressive variants.1 Its clonal nature relies on somatic, gain-of-function mutations in exon 17, causing constitutive activation of the c-KIT proto-oncogene and detected in most patients.2 More than 80% of adult patients with a systemic disease carry a somatic aspartate-to-valine substitution in codon 816 (D816V) of the KIT gene.1 Although it is a putative, non-hereditary disease, familial cases have been reported in paediatric series, with an estimated frequency of 11–13%.3, 4 However, data about the familial occurrence in adults are still lacking.