Nail-patella syndrome (synonyms: Fong’s disease, Trauner-Rieger syndrome) is a rare autosomal dominant condition.

Clinically the key feature is absent/hypoplastic nails from birth.

Diagnostic radiographic findings include the following:
– absent/Hypoplastic patellae (with a tendency to recurrent dislocation)
– Hypoplasia of the radial head or capitellum (leading to subluxation/dislocation)
– Bilateral posterior iliac horns.

The bilateral posterior iliac horns are due to exostoses arising from the posterior aspect of the iliac bones are present in as many as 80% of patients; this finding is considered pathognomonic for the syndrome.

References:
1. Carty et al, Imaging Children p441-2
2. Anna Choczaj-Kukula, Nail-Patella Syndrome EMedicine
3. Dähnert W. Radiology Review Manual 5th edition. Lippincott, Williams & Wilkins 2003

Credit: Dr Ian Bickle, Dr Smitha Vandiyil