Congenital Central Hypoventilation Syndrome

Lifelong breathing disorder

Congenital central hypoventilation syndrome (CCHS) (formerly known as the Ondine curse, after the mythical story) is a disorder of the automatic control of breathing. In CCHS, the body "forgets" to breathe, especially during sleep. Researchers have identified a particular gene defect (PHOX2B) associated with congenital central hypoventilation syndrome, but how the mutation causes the syndrome is not yet known. It is also not known how frequently CCHS occurs, but it is estimated to be a rare disorder.

Symptoms
Infants born with CCHS may have symptoms ranging from mild to severe, including:

• Poor breathing or complete lack of spontaneous breathing, especially during sleep
• Abnormal pupils (70% of individuals)
• Feeding difficulty due to acid reflux and decreased intestinal motility
• An intestinal disorder called Hirschsprung disease (20% of individuals), in which part of the large intestine has no nerves.

Diagnosis
In order to be diagnosed with congenital central hypoventilation syndrome, an individual must have the following:

• Persistent evidence of poor breathing during sleep
• Symptoms begin during the first year of life
• There are no other respiratory or muscular conditions that could account for the breathing difficulty
• There is no evidence of heart disease.

Some infants with CCHS may be mistakenly thought to have heart defects, or to have another type of breathing problem. Unfortunately, some infants with unrecognized CCHS may die and be thought to have had SIDS (Sudden Infant Death Syndrome).

Treatment
If an infant is suspected to have congenital central hypoventilation syndrome, a sleep study is performed to determine how severe the breathing difficulty is. Other special tests of respiratory function can be done as well. Complete cardiac and neurological examinations are done to rule out any other type of disorder. Early diagnosis and treatment are important to prevent serious complications caused by periods of low or no oxygen.

Treatment focuses on providing breathing support, usually through the use of a respirator (ventilator). Some children with CCHS will need a ventilator 24 hours per day; others may only need breathing help when sleeping. In some individuals, a surgical implant in the diaphragm muscle can allow electrical stimulation of the muscle to control breathing.

Children with CCHS are able to lead active lives. They do, however, need close supervision while swimming or playing in pools, since their bodies may "forget" to breathe while underwater. CCHS is a lifelong condition, but with proper treatment it does not alter life expectancy.

Information for this article was taken from:
- Gozal, D. (2002). Ondine curse. eMedicine, accessed at http://www.emedicine.com/ped/topic1645.htm
- J Amiel, B Laudier, T Attié-Bitach, H Trang, L de Pontual, B Gener, D Trochet, H Etchevers, P Ray, M Simonneau, M Vekemans, A Munnich, C Gaultier & S Lyonnet. (March 17, 2003). Polyalanine expansion and frameshift mutations of the paired-like homeobox gene PHOX2B in congenital central hypoventilation syndrome. Nature Genetics, online.