Mitochondrial respiratory chain defects and developmental diaphragmatic dysfunction in the neonatal period.

Mitochondrial respiratory chain disorders are increasingly recognized as common causes of neurological disease and can present at any time from birth through to later in adult life. Although presentation in the neonatal period is rare and few syndromes are described, an association between mitochondrial dysfunction and diaphragmatic problems presenting in the neonatal period has not previously been reported in the literature. Here we report a case series of three newborns that were ventilator-dependent with abnormal diaphragms and became acidotic when required to perform the work of breathing. All were later confirmed to have a mitochondrial respiratory chain disorder following biochemical investigations of muscle tissue, raising the possibility of a link between mitochondrial dysfunction and diaphragmatic involvement.