Biochemically, TRAP activity was undetectable in the patient, while both parents exhibited markedly decreased TRAP levels (mother 1.5 U/l [<4.3 U/l]; father 2.2 U/l [<5.4 U/l]) confirming the diagnosis of SPENCD. This evidence concerns the gene CD40LG and Spondyloenchondrodysplasia with immune dysregulation.