Abnormal Ventilatory Chemosensitivity and Congenital Myopathy

Abstract

Abnormal ventilatory function is common in patients with neuromuscular disorders. This report describes depressed ventilatory response to both hypoxia and hypercapnia, as well as arterial oxygen desaturation during sleep in a family with congenital myopathy. The index patient also had an abnormal ventilatory response to metabolic acid loading. There was clinical evidence of proximal muscle weakness, and a muscle biopsy specimen was consistent with myopathy. The reduction in ventilatory drive, however, could not be explained solely by ventilatory muscle weakness. This report describes a distinct familial syndrome of congenital myopathy and abnormal ventilatory response to hypercapnia and hypoxia. All affected family members had unique facial features, proximal muscle weakness, and impaired ventilatory responses. The combination of impaired ventilatory drive and reduced ventilatory muscle strength leaves patients particularly vulnerable, and heightened awareness of this association is important in the treatment of these patients.