Nail-patella syndrome

Last revised by Dr Ian Bickle on 02 Aug 2021

Nail-patella syndrome (also known as Fong disease, osteo-onychodysostosis, Österreicher-Turner syndrome 10, Turner-Kieser syndrome, and Trauner-Rieger syndrome) is a rare autosomal dominant condition which results from symmetrical mesodermal and ectodermal abnormalities.

Clinically, the key feature is absent or hypoplastic nails from birth. Individuals may have flexion contractures and recurrent knee dislocations.

The underlying genetic defect is caused by loss-of-function mutations in the transcription factor LMX1B on chromosome 9 5,6.

  • renal dysfunction 5

Diagnostic radiographic findings include:

  • fragmented/absent/hypoplastic patellae with a tendency for recurrent patellar dislocation
  • hypoplasia of the radial head and/or capitellum leading to subluxation or dislocation dorsally
  • bilateral posterior iliac horns ("Fong prongs")
  • flared iliac crests with protuberant anterior iliac spines

The bilateral posterior iliac horns, 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. The horns may be capped by an epiphysis. Other features include:

For absent patella(e), consider:

  • popliteal pterygium syndrome
  • surgical removal of the patella
  • small patella syndrome (ischiopatellar dysplasia)
  • Meier-Gorlin syndrome

Iliac horns were described by Edward Everett Fong (b. 1912- fl. 1964 9), an American radiologist in 1946 8.

Multidisciplinary teams are required to treat patients with Nail-patella syndrome, these include orthopedics, pediatricians and other complications of the conditions: nephrologists, ophthalmologists, general practitioners, dieticians, and physiotherapists to name a few 12.

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Cases and figures

  • Case 1: close up
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  • Case 2
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  • Case 3
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  • Case 4
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  • Case 5
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  • Case 7: large tibial tuberosities
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  • Case 8: absent ossificastion center of the patella
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  • Case 9: knee
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  • Case 9: pelvis
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  • Case 9: pelvis CT
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  • Case 9: elbow
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  • Case 10: iliac horns
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