ADAMDEC1 is a unique member of the ADAM family: it contains pro- and catalytic domains but has a truncated disintegrin domain and lacks the typical transmembrane domain and cytoplasmic tail.13 It is believed to be a soluble, secreted protein and has recently been identified in osteoarthritis synovial fluid5 and in the supernatant from un-stimulated ADAMDEC1-transfected HEK293 cells.14 It is predicted that the disintegrin site is non-functional as the ‘disintegrin loop’, reported to be essential for integrin binding,13 is missing. The gene discussed is ADAMDEC1; the disease is osteoarthritis.