NPY and obesity due to melanocortin 4 receptor deficiency: In contrast, neuropeptide Y (NPY) contributes to obesity-related OSAS through its involvement in appetite stimulation, fat accumulation via hypothalamic pathways [3, 9] and amplification of hypoxic stress via peptidylglycine α-amidating monooxygenase (PAM)–mediated upregulation during intermittent hypoxia [10].