Abnormal ventilatory control in patients with Prader-Willi syndrome when awake and sleeping include abnormal responses to hyperoxia, hypoxia and hypercarbia. Lindgren et al., report similar results regarding response to hypoxia; however, they have demonstrated significant minute ventilation and carbon dioxide responses in their patients treated with growth hormone irrespective of body mass index. It is possible that the explanation for the abnormal respiratory control in this syndrome is located in central rather than peripheral structures. The hypothalamus stands out as the possible location that links their abnormal ventilatory control with the other features. Further investigations to correlate this finding are warranted.