SNCA and obstructive sleep apnea syndrome: The hypothesis surrounding OSA is PD related loss of functioning neurons in myofibers and their subsequent atrophy, degeneration of the peripheral nerves innervating the oropharyngeal muscles, alpha-synuclein deposition in the fibers of the vagus nerve, supplying the laryngeal and pharyngeal muscles, and the episodic upper airway movement disorders caused by nocturnal dyskinesia may play a pivotal role in the development of obstructive sleep apnea.