Nail-patella syndrome
Updates to Article Attributes
Nail-patella syndrome, also known as Fong disease or osteo-onychodysostosis, is a rare autosomal dominant condition which results from symmetrical mesodermal and ectodermal abnormalities.
Clinical presentation
Clinically, the key feature is absent/hypoplastic nails from birth. Individuals may have flexion contractures and recurrent knee dislocations.
Pathology
The underlying genetic defect is caused by loss-of-function mutations in the transcription factor LMX1B on chromosome 9 5,6.
Associations
- renal dysfunction 5
Radiographic features
Plain radiograph
Diagnostic radiographic findings include:
- absent/hypoplastic patellae (with a tendency to recurrent dislocation)
- hypoplasia of the radial head or capitellum (leading to subluxation/dislocation)
- bilateral posterior iliac horns ("Fong prongs")
- 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:
- scoliosis
- genu valgum deformity
- flared iliac crests
- open angle glaucoma 6
- prominent tibial tuberosities
- clinodactyly
- short 5th metacarpal
- renal osteodystrophy
Differential diagnosis
For absent patella(e), consider:
History and etymology
Iliac horns were described by Edward Everett Fong (b. 1912), an American radiologist in 1946 8.
-<p><strong>Nail-patella syndrome</strong>, also known as <strong>Fong disease </strong>or <strong>osteo-onychodysostosis</strong>, is a rare autosomal dominant condition which results from symmetrical mesodermal and ectodermal abnormalities.</p><h4>Clinical presentation</h4><p>Clinically, the key feature is absent/hypoplastic nails from birth. Individuals may have flexion contractures and recurrent knee dislocations.</p><h4>Pathology</h4><p>The underlying genetic defect is caused by loss-of-function mutations in the transcription factor <em>LMX1B</em> on chromosome 9 <sup>5,6</sup>.</p><h5>Associations</h5><ul><li>renal dysfunction <sup>5</sup>- +<p><strong>Nail-patella syndrome</strong>, also known as <strong>Fong disease </strong>or <strong>osteo-onychodysostosis</strong>, is a rare autosomal dominant condition which results from symmetrical mesodermal and ectodermal abnormalities.</p><h4>Clinical presentation</h4><p>Clinically, the key feature is absent/hypoplastic <a title="Nail" href="/articles/nail">nails</a> from birth. Individuals may have flexion contractures and recurrent <a title="Knee dislocation" href="/articles/knee-dislocation">knee dislocations</a>.</p><h4>Pathology</h4><p>The underlying genetic defect is caused by loss-of-function mutations in the transcription factor <em>LMX1B</em> on chromosome 9 <sup>5,6</sup>.</p><h5>Associations</h5><ul><li>renal dysfunction <sup>5</sup>
-</ul><p>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:</p><ul>- +</ul><p>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 <a title="Pathognomonic" href="/articles/pathognomonic">pathognomonic</a> for the syndrome. The horns may be capped by an epiphysis. Other features include:</p><ul>
-</ul><h4>History and etymology</h4><p>Iliac horns were described by <strong>Edward Everett</strong> <strong>Fong </strong>(b. 1912), an American radiologist.</p>- +</ul><h4>History and etymology</h4><p>Iliac horns were described by <strong>Edward Everett</strong> <strong>Fong </strong>(b. 1912), an American radiologist in 1946 <sup>8</sup>.</p>
References changed:
- 8. Fong E. Iliac Horns (Symmetrical Bilateral Central Posterior Iliac Processes). Radiology. 1946;47(5):517. <a href="https://doi.org/10.1148/47.5.517">doi:10.1148/47.5.517</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/20274622">Pubmed</a>
Systems changed:
- Paediatrics
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