The nail-patella syndrome (onycho-osteodysplasia) is a well-known hereditary disorder characterized by four typical abnormalities including dysplasia of the fingernails, hypoplasia of the patella and lateral femoral condyle, dysplasia of the radial head and lateral condyle of humerus with posteriorly radial head dislocation, and anormalous bony projections from the ilia, known as iliac horns. It is transmitted as an autosomal dominant trait and linked on the chromosome with the ABO blood group gene. Its incidence was relatively rare and only few cases were reported in our country. Authors report one affected family case in this paper.