The cause of this disease is unknown. Current research is looking at how the brain of these patients may be less responsive to carbon dioxide.

The condition is usually worse during sleep, and periods of apnea (where the breathing stops) are usually present. Patients with this disease are extremely sensitive to even small doses of sedatives or narcotics, which can make their inadequate breathing much worse. The disease primarily affects men 20 to 50 years old. It can also be present in male children.

This condition is commonly seen in those with obesity hypoventilation syndrome.

• lethargy
• fatigue
• morning headache
• daytime somnolence
• swelling of the ankles
• bluish coloration of the skin caused by lack of oxygen
• awakening from sleep unrested
• awakening many times at night

• pulmonary function tests
• blood gases
• chest X-ray to rule out other diseases
• overnight oximetry (a test to measure oxygen levels during the night)
• Sleep study (polysomnography)

This disease may also alter the results of the following tests:

• serum bicarbonate
• hematocrit