A rare case of bone dysplasia with moderate modelling anomalies of the long bones, joint dislocation, osteolysis, a congenital calvarial defect, a patent ductus arteriosus, a mild degree of hypospadias and hypertensive renal cystic dysplasia is presented. In spite of many similarities with the Hajdu - Cheney Syndrome (HCS), important dissimilarities indicate that this case may be either an extreme variant of HCS, or a closely related, separate entity for which the term Arthro-Osteo-Renal Dysplasia is proposed.