THBS4 and X-linked hypophosphatemic rickets: Since we have previously identified Thbs4 as a marker of articular cartilage [15], our main interest was an in-depth skeletal phenotyping of Thbs4-deficient mice, thereby also addressing the question, whether its increased expression in bones from Hyp mice is relevant for the pathogenesis of X-linked hypophosphatemic rickets [24].