Energy Balance and Mitochondrial Function in Human Genetic Models of Mitochondrial Stress-mediated Obesity Resistance

Background: Pre-clinical models of mitochondrial stress are resistant to diet-induced obesity. Likewise, humans with primary mitochondrial diseases present a high prevalence of underweight (42%) as compared to a very low prevalence of obesity (2%). In this direction, recent data show a lower BMI across 17 cohorts of patients with mitochondrial diseases compared to national averages, suggesting mitochondrial stress-induced increments in resting energy expenditure as the primary driver of the lean phenotype. In recent years, the study of humans with genetic mutations has shown enormous potential to establish the mechanistic link between two physiological variables; indeed, if the mutation has a functional impact on one of those variables, then the direction of causality can be readily ascribed. Taken together, studies integrating assessments of energy balance with mitochondrial phenotyping in patients with rare mitochondrial disorders hold the potential to uncover putative mechanisms conferring protection from obesity in humans.