Hereditary Osteo-onychodysplasia Disease

Hereditary osteo-onychodysplasia disease (HOOD), also known as Nail Patella Disease or Iliac Horn Syndrome is a genetic disorder due to an autosomal dominant mutation in the LMX1B gene. A pathognomonic finding is the presence of "iliac horns" projecting posterolaterally from the bilateral iliac bones. Other associated findings are absence or hypoplasia of the patella and radial head. Nail deformities are also common.  The joint deformities can lead to osteoarthritis. About 40% of patients may also develop renal disease ranging from proteinuria to nephrotic syndrome.

Above, the lateral radiograph of the knee is from a patient who presented to the emergency room after a fall. A hypoplastic patella was incidentally noted. A review of prior imaging demonstrated bilateral iliac horns best seen on the scout image.


REFERENCES
Scott JE and Taor WS. The small patella syndrome. J Bone Joint Surg [Br] 1979;61-B:172-5.
Thompson EA, Walker T, Weens HS. Iliac horns. An osseous manifestation of hereditary arthrodysplasia associated with dystrophy of the fingernails. Radiology 1949;53:88-92.
Tuncbilek N, Karakas HM, Okten OO. Imaging of nail-patella syndrome. Hong Kong Med J 2005;11(2):116-8.