Central congenital hypoventilation syndrome: changing face of a less mysterious but more complex genetic disorder.

Central congenital hypoventilation syndrome (CCHS) is a disorder in which affected individuals fail to breathe during sleep despite progressive hypercapnia and hypoxia. Discovery of the genetic link between PHOX2B gene mutations and CCHS represents a breakthrough in the diagnosis of CCHS, identification of patients with late-onset central hyperventilation syndrome (LO-CHS), association of mutated alleles with disease severity, and clues to the pathophysiology responsible for the disorder. CCHS is a neurocristopathy, and affected individuals are more likely to have disorders of the autonomic nervous system, Hirschsprung disease, and neural crest tumors. Most CCHS patients harbor sporadic mutations, but identification of an affected individual should trigger evaluation of family members because inherited mutations are transmitted in an autosomal dominant fashion. Management of CCHS and LO-CHS is primarily directed at optimizing respiratory status, most often with nighttime mechanical ventilatory support and monitoring with polysomnography. Multidisciplinary care is also necessary to promote better outcomes and long-term survival.