Multisuture Craniosynostosis and Papilledema in Pycnodysostosis: A Paradox?
Gregory P L Thomas1, Shailendra A Magdum1, Nad R Saeed2
1Oxford Craniofacial Unit.
Insights
Pycnodysostosis (PYCD) is a rare skeletal disorder. A unique case highlights multisuture craniosynostosis, successfully treated with frontofacial monobloc distraction advancement.
Area of Science:
- Genetics
- Skeletal Biology
- Pediatric Surgery
Background:
- Pycnodysostosis (PYCD) is a rare autosomal-recessive skeletal disorder characterized by osteosclerosis and osteolysis.
- It results from loss-of-function mutations in the CTSK gene, affecting osteoclast function.
- Craniosynostosis is an uncommon manifestation of PYCD.
Observation:
- A 6-year-old girl with PYCD presented with multisuture craniosynostosis (coronal and sagittal sutures).
- She also exhibited severe obstructive sleep apnea and papilledema due to raised intracranial pressure.
- This presentation is paradoxical given typical PYCD bone remodeling patterns.
Findings:
- The patient underwent frontofacial monobloc distraction advancement.
- This surgical intervention successfully corrected both the papilledema and obstructive sleep apnea.
Implications:
- This case demonstrates the successful surgical management of craniosynostosis in PYCD.
- It highlights the potential for significant improvement in associated respiratory and neurological symptoms.
- Understanding the genetic and cellular basis of PYCD may inform future treatment strategies for complex skeletal disorders.
Abstract:
Pycnodysostosis (PYCD) is a rare autosomal-recessive skeletal disorder that typically presents with osteosclerosis of the majority of the postcranial skeleton and osteolysis of the calvarium, manifesting as persistent open cranial fontanelles and widely spaced cranial sutures. Craniosynsostosis in PYCD is a somewhat paradoxical feature, and has only been rarely reported. The authors present a unique case of a 6-year-old girl with PYCD, multisuture craniosynostosis involving the coronal and sagittal sutures, severe obstructive sleep apnoea, and raised intracranial pressure presenting as papilledema. She underwent a frontofacial monobloc distraction advancement which successfully corrected her papilledema and obstructive sleep apnoea.Pycnodysostosis is caused by a loss of function mutation in the CTSK gene that codes for the lysosomal cysteine protease, cathepsin K (CTSK). Loss of CTSK impairs the ability of osteoclasts to degrade bone extracellular matrix. Differences in osteoclast phenotype and extracellular matrix composition between membranous and cartilaginous bone may explain the clinical features of PYCD. Animal model studies suggest that craniosynostosis may arise due to variations in patient genetic background.
