Diagrams summarizing the mutations identified in CD70 and LYN. Mutations affecting the CD70 gene were often protein truncating or located at the donor splice site of the exon 2 (A). Mutations in LYN were most often located in the kinase domain of the protein, thus potentially affecting signal transduction through this molecule (B). Wild-type and mutant LYN constructs were transfected into U2OS cells and protein expression detected by immunoblotting. Mutations tested affected LYN’s expression to variable levels (C). neg, negative control (without transfection).