Congenital central alveolar hypoventilation  usually manifests at birth with shallow,
erratic, or absent breathing. This disorder can also manifest during infancy, childhood,
and adulthood because of va riable penetrance of the PHOX2B  mutation. Children with
congenital central alveolar hypo ventilation are more likely to have disorders of the auto-
nomic nervous system, Hirschsprung’s disease, neural crest tumors, and characteristic box-
shaped face (i.e., the face is short relative to its width).
Risk and Prognostic Factors
Environmental. Ventilatory drive can be reduced in  individuals using central nervous
system depressants, including benzod iazepines, opiates, and alcohol. 
Genetic and physiological. Idiopathic sleep-related hypoventilation is associated with
reduced ventilatory drive due to a blunted chemoresponsiveness to CO2 (reduced respi-
ratory drive; i.e., “won’t brea the”), reflecting underlying neurological deficits in centers
governing the control of ventilation. More co mmonly, sleep-related hypoventilation is co-
morbid with another medical condition, su ch as a pulmonary diso rder, a neuromuscular
or chest wall disorder, or hypothyroidism, or with use of medications (e.g., benzodiaze-
pines, opiates). In these conditions, the hy poventilation may be a consequence of in-
creased work of breathing and/or impairment of respiratory muscle function (i.e., “can’t
breathe”) or reduced respiratory drive (i.e., “won’t breathe”).
Neuromuscular disorders influence breathin g through impairment of respiratory mo-
tor innervation or respiratory muscle function. They include conditions such as amyo-