Pycnodysostosis presenting as atypical stridor

Pycnodysostosis is a rare genetic disorder caused by a mutation of the cathepsin K gene involved in bone turnover. It is responsible, in particular, for a combination of dwarfism and bone fragility. Upper airway obstruction may be observed, but associated stridor has never been previously described.

Single-centre retrospective study over a period of 15 years with review of the literature.

Three children (aged 2-18 months) were managed for stridor and obstructive sleep apnoea syndrome confirmed by polysomnography. Physical examination of these children revealed stridor with laryngomalacia, characteristic dysmorphic features and failure to thrive. Patient 1 presented typical laryngomalacia treated by surgical section of the aryepiglottic folds. Patient 2 presented upper airway obstruction with a narrow nasopharynx and long soft palate, treated by surgery and noninvasive ventilation. Patient 3 presented moderate laryngomalacia and nasal obstruction, treated by surgery and noninvasive ventilation.

The diagnosis of pycnodysostosis must be considered in the presence of atypical laryngomalacia associated with multifactorial upper airway obstruction, failure to thrive and dysmorphic syndrome. A genetics consultation is essential in these patients.