Onychodysplasia occurs in 80-90% of patients. Over 90% of NPS patients exhibit abnormalities of the knee – hypoplastic or absent patella. Common elbow changes are dysplasia of the radial head, hypoplasia of the lateral epicondyle, prominence of the medial epicondile, antecubital pterygia witch may result in dislocation of the radial head, limitation of extension, pronation and supination of the forearm. Iliac horns observed in about 80% of the patients are pathognomonic for NPS [8,9]. Other bone involvement may consist of cervical rib, hypoplasia of the lateral femural condyle and the humeral condyles (capitellum), small head of the fibula, scoliosis [10]. Renal involvement occurs in less than half of the NPS patients. Symptoms in- clude microscopic hematuria and mild proteinuria, which typically appear in adolescence or young adulthood. Occasionally patients develop nephrotic syndrome (NS), hypertension, renal failure [11].
249Other systemic involvements include ophthalmic problems (cataract, glaucoma) [12], sensorineural hearing loss and, occasionally, mental retardation.