Pyknodysostosis

Changed by Rohit Sharma, 7 Mar 2018
Back to revision history

Updates to Article Attributes

Body was changed:

Pyknodysostosis, also known as osteopetrosis acro-osteolytica or Toulouse-Lautrec syndrome, is a rare autosomal recessive bone dysplasia, characterised by osteosclerosis and short stature. 

Pathology

Pyknodysostosis is a lysosomal disorder due to genetic deficiency in Cathepsin K which has been mapped to chromosome 1q21. Cathepsin K is essential for normal osteoclast function.

Clinical presentation

Patients present in early childhood with:

  • short stature, particularly limbs
  • delayed closure of cranial sutures
  • frontal and and occipital bossing
  • short broad hands and hypoplasia of nails
  • multiple long bone fractures following minimal trauma

Pathology

Pyknodysostosis is a lysosomal disorder due to genetic deficiency in cathepsin K which has been mapped to chromosome 1q21. Cathepsin K is essential for normal osteoclast function.

Radiographic features

Osteosclerosis with narrowed medullary cavities is the main generalised imaging finding. Long bone fractures are common. Obtuse angle of the mandible. Lack/abnormal teeth. 

Plain radiograph / CT
Hands
  • short, stubby fingers
  • partial agenesis/aplasia of terminal phalanges, simulating acro-osteolysis
  • delayed bone age 
Cranial and maxillofacial
  • marked delay in sutural closure
  • frontoparietal bossing
  • calvarial thickening
  • Wormian bones (lambdoidal region)
  • relative proptosis
  • nasal beaking
  • obtuse mandibular gonial angle often with relative prognathism
  • persistence of primary teeth
Other

History and etymology

Derived from the greek terms "pucnos" (dense), "dys" (defective) and "ostosis"(bone condition). 

The condition is also known as Toulouse-Lautrec syndrome, named after the famous French artist Henri Marie Raymond de Toulouse-Lautrec-Monfa (1864-1901) who was thought to be afflicted with the disease.

Differential diagnosis

General imaging differential considerations include:

  • -<p><strong>Pyknodysostosis</strong>, also known as <strong>osteopetrosis acro-osteolytica </strong>or <strong>Toulouse-Lautrec syndrome</strong>, is a rare autosomal recessive bone dysplasia, characterised by osteosclerosis and short stature. </p><h4>Pathology</h4><p>Pyknodysostosis is a lysosomal disorder due to genetic deficiency in Cathepsin K which has been mapped to chromosome 1q21. Cathepsin K is essential for normal osteoclast function.</p><h4>Clinical presentation</h4><p>Patients present in early childhood with:</p><ul>
  • +<p><strong>Pyknodysostosis</strong>, also known as <strong>osteopetrosis acro-osteolytica </strong>or <strong>Toulouse-Lautrec syndrome</strong>, is a rare autosomal recessive bone dysplasia, characterised by osteosclerosis and short stature. </p><h4>Clinical presentation</h4><p>Patients present in early childhood with:</p><ul>
  • -<a href="/articles/frontal-bossing">frontal</a> and occipital bossing</li>
  • +<a href="/articles/frontal-bossing">frontal</a> and occipital bossing</li>
  • -</ul><h4>Radiographic features</h4><p><a href="/articles/osteosclerosis">Osteosclerosis</a> with narrowed medullary cavities is the main generalised imaging finding. Long bone fractures are common. Obtuse angle of the mandible. Lack/abnormal teeth. </p><h5>Plain radiograph / CT</h5><h6>Hands</h6><ul>
  • +</ul><h4>Pathology</h4><p>Pyknodysostosis is a lysosomal disorder due to genetic deficiency in cathepsin K which has been mapped to chromosome 1q21. Cathepsin K is essential for normal osteoclast function.</p><h4>Radiographic features</h4><p><a href="/articles/osteosclerosis">Osteosclerosis</a> with narrowed medullary cavities is the main generalised imaging finding. Long bone fractures are common. Obtuse angle of the mandible. Lack/abnormal teeth. </p><h5>Plain radiograph / CT</h5><h6>Hands</h6><ul>
  • -</ul><h4>History and etymology</h4><p>Derived from the greek terms "pucnos" (dense), "dys" (defective) and "ostosis"(bone condition). </p><p>The condition is also known as <strong>Toulouse-Lautrec </strong>syndrome, named after the famous French artist who was thought to be afflicted with the disease.</p><h4>Differential diagnosis</h4><p>General imaging differential considerations include:</p><ul>
  • +</ul><h4>History and etymology</h4><p>Derived from the greek terms "pucnos" (dense), "dys" (defective) and "ostosis"(bone condition). </p><p>The condition is also known as <strong>Toulouse-Lautrec </strong>syndrome, named after the famous French artist <strong>Henri Marie Raymond de Toulouse-Lautrec-Monfa</strong> (1864-1901) who was thought to be afflicted with the disease.</p><h4>Differential diagnosis</h4><p>General imaging differential considerations include:</p><ul>

Sections changed:

ADVERTISEMENT: Supporters see fewer/no ads