Idiopathic Hypersomnia in a Patient Suffering from MELAS (Mitochondrial Myopathy, Encephalopathy, Lactic Acidosis, and Stroke-Like Episodes): a New Mitochondrial Feature?

Hypersomnia is a rare neurologic disorder characterized by an excessive daytime sleepiness with long naps, despite an undisturbed nocturnal sleep. The impaired daytime alertness and sleep inertia are different from general fatigue. This disorder is often classified as idiopathic. Here, we report the case of a young patient presenting both a mitochondrial disease and a hypersomnia. We discuss the links between the two pathologies and propose to systematically investigate personal and familial mitochondrial features in case of hypersomnia, to offer suitable genetic tests. Conversely, fatigue could be one of the complaints reported by patients with a confirmed mitochondrial disease, which is multifactorial. Sleep quality and somnolence should be examined in these patients as specific treatments exist for this debilitating disorder.