Abstract: Objective To analyze the clinical, laboratory examination and pathogenic genes of a case of congenital central hypopnea syndrome (CCHS). Methods The clinical manifestations, laboratory examination, echocardiography, treatment and follow-up of a child with CCHS with unexplained pulmonary hypertension were collected.The genes of the child and his parents were detected by targeted capture second generation sequencing technique. The reported pathogenic genes of CCHS were verified by Sanger method, and the clinical characteristics, pathogenic mechanism and gene mutation of CCHS were summarized and discussed in combination with domestic and foreign literature. Results The main manifestations of 11 -monthold girls were edema, oliguria, hypotension, lethargy, cyanosis,convulsions; increased intracranial pressure, MRI suggested right frontal lobe hemorrhage; brain natriuretic peptide (BNP), glutamic pyruvic transaminase increased and prothrombin time prolonged;echocardiography showed moderate and severe pulmonary hypertension. No possible pathogenic genes were found in the second generation of targeted capture sequencing.After non-invasive ventilation,the breathing of the children was slow and weak during sleep, accompanied by a decrease in blood oxygen, and blood gas analysis showed carbon dioxide retention. The polyalanine repeat expansion mutation in exon 3 of PHOX 2 B was confirmed by Sanger method. Then the patients were treated with nocturnal non-invasive ventilation and antihypertensive drugs. The pulmonary artery pressure decreased significantly and the vital signs were stable.During the follow-up to 24 months old, only non-invasive ventilation with low pressure level was needed at night, and the growth and development was normal. Conclusion For children with unexplained pulmonary hypertension with difficulty in weaning, patients with suspected CCHS, should carry out the second generation of targeted capture sequencing of CCHS-related genes and Sanger verification of PHOX 2 B gene as soon as possible, which can avoid missed diagnosis of CCHS; and early non-invasive ventilation can improve the prognosis.

Key words: congenital central hypopnea syndrome; pulmonary hypertension; PHOX 2 B gene; child