Phenotype and CLCN7 mutations of autosomal dominant osteopetrosis type II (ADO II) patients. (a) Localization of the different CLCN7 mutations presented by the patients (adapted from Dutzler et al67). The patients presented six different CLCN7 mutations variously positioned on the CLC7 protein, with three of them localized in the intracellular C-terminal region, and the others in the transmembrane region. The most common mutation, p.G215R, was present in five of our osteopetrotic patients. (b) The levels for serum bone markers such as bone alkaline phosphatase (BAP), tartrate-resistant acid phosphatase (TRAP), serum type 1 collagen C-terminal telopeptide (CTx), the CTx/TRAP ratio, and serum total type I procollagen N-terminal propeptide (P1NP), and the femoral BMD Z-score of 14 out of 15 osteopetrotic patients are shown here. The gray zone corresponds to the normal range. (c and d) Typical X-ray features of osteopetrotic patients. (c) Dense bands of sclerosis parallel to the vertebral endplates (‘sandwich vertebrae’, arrowheads) and (d) concentric arcs of sclerosis within the iliac wings (‘bone within bone’).