Government leadership in tobacco control: Brazil's experience.

Congenital central hypoventilation syndrome (CCHS) is a rare condition for which segregation analyses have suggested genetic factors. The respiratory phenotype of Rnx knock-out mice together with the Rnx expression at the brainstem level prompted us to consider the RNX gene as a candidate for CCHS in human. The screening of the RNX gene in a series of 25 patients with CCHS did not reveal any significant nucleotide variation. We therefore conclude that RNX is not a major gene for CCHS in human.