This case report involves a 10-yr-old boy diagnosed with spinal muscular atrophy type 2 who underwent nighttime mechanical ventilation with bilevel positive airway pressure. The oral examination revealed restricted mouth opening, lip interposition, dental crowding, and maxillary compression. After maxillary expansion, the upper airway volume increased 18.6%; 13 episodes of airway infections (20 days of hospitalization) were recorded in the 2 yrs before the maxillary expansion and only 4 episodes (no hospital admissions) in the 2 subsequent years. In conclusion, maxillary expansion in children with systemic disease that involves respiratory impairment may, in some cases, provide functional and clinical improvements, increase upper airway airflows, and possibly decrease the number of respiratory infections.