Some aspects of respiratory function in three siblings with Morquio-Brailsford disease.

Morquio-Brailsford disease is a rare genetic disorder of mucopolysaccharide metabolism, and its features include dwarfism and thoracic deformity. A boy aged 15 with this condition developed respiratory failure and later died. This boy and his two affected female siblings were studied and the results are presented. The height of the lungs was less than the anteroposterior diameter on standard chest radiographs. All had small lungs without evidence of airways obstruction. Measurements of dependent airway closure were made in the erect and supine positions. These showed some abnormalities which could cause ventilation-perfusion imbalance. Possible mechanisms leading to the development of respiratory failure in this condition are discussed, including nasopharyngeal obstruction, thoracic deformity, and disturbed ventilation-perfusion relationships. The importance of respiratory failure as a cause of death in Morquio's disease is emphasized.