• respiratory failure [ Time Frame: cross sectional observation ] [ Designated as safety issue: No ]
  

Background: Congenital central hypoventilation syndrome (CCHS) is characterized by compromised chemo-reflexes that results in hypoventilation during sleep. Recently, a heterozygous PHOX2B gene mutation was identified in CCHS. This report was made to increase physicians' awareness of this rare disease.

Methods: A Chinese family of CCHS with presentations from newborn to adulthood and genetic analysis confirming the PHOX2B mutation was analyzed. After identifying central hypoventilation in an adult male (index case), clinical evaluation was performed on the complete family, which consisted of the parents, five siblings, and five offsprings. In addition, pulmonary function test, overnight polysomnography, arterial blood gas, and hypercapnia ventilatory response, and genetic screening for PHOX2B gene mutations were performed on living family members.

Results: The index patient and four offsprings demonstrated features of central hypoventilation. The index patients had hypoxia and hypercapnia while awake and breathing room air, nocturnal hypoventilation with nadir SpO2 of 50%, and polycythemia with hematocrit 70%. The first and fourth children had frequent cyanotic spells after birth and died of respiratory failure. The second and third children remained asymptomatic till adulthood but had decreased hypercapnic ventilatory response. The third child had nocturnal hypoventilation with nadir SpO2 of 59%. PHOX2B gene five alanine expansions were detected in all affected living subjects, including the index patient and two (second and third) children.

Conclusions: Our study confirms that the transmission of late-onset CCHS is autosomal-dominant and genetic screening of family members for CCHS probands allows for early diagnosis and treatment.