In the other 56 patients in whom we identified a COMP, MATN3 or type IX collagen gene mutation, the majority had been referred to ESDN with a diagnosis of MED (Table 3), which would indicate that the “classical” forms of MED (i.e., those patients in whom we identified a mutation) are also relatively easy to diagnose. This evidence concerns the gene COMP and multiple epiphyseal dysplasia.