Pycnodysostosis presenting as atypical stridor.

Area of Science:

• Genetics
• Pediatrics
• Otolaryngology

Background:

• Pycnodysostosis (OMIM 201775) is a rare autosomal recessive disorder caused by mutations in the cathepsin K gene (CTSK).
• It is characterized by skeletal abnormalities including osteopetrosis, short stature, bone fragility, and characteristic facial features.
• While upper airway obstruction is a known complication, stridor has not been previously reported.

Observation:

• This study reports on three infants (2-18 months) diagnosed with pycnodysostosis who presented with stridor and obstructive sleep apnea syndrome.
• Clinical findings included laryngomalacia, dysmorphic features, and failure to thrive.
• All patients required multidisciplinary management for their airway issues.

Findings:

• Patient 1: Laryngomalacia treated with surgical section of aryepiglottic folds.
• Patient 2: Severe upper airway obstruction (narrow nasopharynx, long soft palate) managed with surgery and non-invasive ventilation.
• Patient 3: Moderate laryngomalacia and nasal obstruction treated with surgery and non-invasive ventilation.

Implications:

• Atypical laryngomalacia associated with multifactorial upper airway obstruction, failure to thrive, and dysmorphic features should prompt consideration of pycnodysostosis.
• Genetic counseling and testing are essential for early diagnosis and management.
• This highlights a novel association that expands the clinical spectrum of pycnodysostosis.