Small patella syndrome: a bone dysplasia to recognize and differentiate from the nail-patella syndrome.

We report a 5-year, 9-month-old boy with bilateral patellar hypoplasia. The radiographic skeletal survey revealed absent ossification of the ischium and inferior pubic ramus on both sides, characteristic of the newly recognized benign bone dysplasia known as small patella syndrome, or ischiopatellar dysplasia. No nail change, iliac horn, elbow anomaly, or renal disease is associated with this condition.