Abstract Introduction Congenital central hypoventilation (CCHS) is a rare disorder due to impairment of autonomic nervous system clinically defined by a significantly reduced or abolished ventilatory response to hypercapnia and hypoxemia in the absence of pulmonary, neuromuscular, or cardiac disease. There is limited knowledge on associated respiratory manifestations and sleep-disordered breathing in children with the MECP2 duplication syndrome. Although sleep-disordered breathing and nocturnal hypoventilation are currently not well recognized in these children, we present a case of a patient with MECP2 mutation and congenital hypoventilation syndrome. Report of case(s) 24-week-old male born full-term via c-section presented with recurrent respiratory problems, laryngeal cleft, dysphagia, snoring and apneic episodes. Previous genetic work up showed chromosome 15q11.2 microdeletion. Past medical history was significant for neonatal ICU stay for respiratory distress immediately following birth. Tonsils are 1+ on exam. PSG showed profound central sleep apnea (CAI 300/h) with average apneic episodes lasted for 7 seconds and very significant periodic breathing (88%) and mild obstructive apnea. Mild hypoxemia was also seen with SpO2 in low 90s without any significant hypercapnia. Bradypnea with resp rate 10-20/m was seen. PHOX2B gene testing was negative. Genetic testing with SNP array showed MECP2 duplication syndrome. His development is delayed, currently at the age of 20 months, including cognitive, speech and motor function for which he is on therapy. Tracheostomy was recommended, however family preferred to continue with non-invasive ventilation while awaiting diaphragmatic pacing. Conclusion Respiratory manifestations in MECP2 duplication syndrome patients are common, with important impact and even a possible fatal outcome. Although sleep-disordered breathing and nocturnal hypoventilation is currently not cited as an important symptom in these children, there have been several case reports of CCHS associated with this. PSG should be considered in patients with MCEP2 duplication syndrome for timely diagnosis. Different treatment modalities (ENT surgery, CPAP and NIV) can be applied successfully to treat respiratory conditions associated with MECP2 duplication syndrome. Support (if any)