title: Congenital central hypoventilation syndrome and carbon dioxide sensitivity.
abstract: Congenital central hypoventilation syndrome (CCHS) is characterised by hypoventilation most marked during sleep and is often associated with abnormalities of the autonomic nervous system. We report an infant with severe CCHS and Hirschsprung disease in whom, while awaiting genotyping, the diagnosis was facilitated by the results of a carbon dioxide (CO2) sensitivity study in the neonatal period and was confirmed by paired-like homeobox 2B (PHOX2B) mutational analysis. The infant had no ventilatory response to increased inspired carbon dioxide levels when either awake or asleep suggesting he had a severe form for CCHS; indeed, he subsequently demonstrated to have the 20/31 genotype. This is the first case report of a genotype-confirmed CCHS disease in a neonate with Hirschsprung disease further characterised by a ventilatory challenge.
  
  
  CONCLUSIONS
  CO2 sensitivity status may assist in determining the severity of the CCHS.
authors.affiliation: Division of Asthma, Allergy and Lung Biology, MRC Centre for Allergic Mechanisms in Asthma, King's College London, London, UK, thomas.rossor@kcl.ac.uk.
authors.forename: Thomas
authors.initials: T
authors.lastname: Rossor
authors.forename: Aung
authors.initials: A
authors.lastname: Soe
authors.forename: Ravindra
authors.initials: R
authors.lastname: Bhat
authors.forename: Anne
authors.initials: A
authors.lastname: Greenough
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism*; D004247:DNA / Q000235:genetics*; D004252:DNA Mutational Analysis; D020022:Genetic Predisposition to Disease; D005838:Genotype; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D006935:Hypercapnia / Q000151:congenital* / Q000235:genetics / Q000378:metabolism; D007040:Hypoventilation / Q000151:congenital* / Q000235:genetics / Q000378:metabolism; D007231:Infant, Newborn; D008297:Male; D009419:Nerve Tissue Proteins; D020182:Sleep Apnea, Central / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D018398:Homeodomain Proteins; C109220:NBPhox protein; D009419:Nerve Tissue Proteins; D014157:Transcription Factors; D002245:Carbon Dioxide; D004247:DNA