Characteristics of breathing abnormality in Leigh and its overlap syndromes.

In this report we describe the respiratory patterns of six patients with Leigh syndrome, including two individual cases with accompanying clinical phenotypes of Alpers disease and mitochondrial encephalopathy with ragged red fibers. In five cases where sleep apnea was monitored, each one showed isolated or post-sigh central apnea, hiccup, apneusis-like breathing and obstructive apnea in various combinations. The remaining patient with Alpers/Leigh overlap syndrome showed an apneusis-like pattern of dyspnea. The sleep structure was examined in three patients. Two patients with brainstem lesions showed a decrease in the deep sleep stages and an absence of REM sleep. Medullary lesions were found in four patients by magnetic resonance imaging or at autopsy and involved predominantly the dorsal respiratory group (DRG) of medullary neurons. The role of DRG lesions in the pathophysiology of respiratory symptoms in Leigh syndrome is discussed.