What Is Central Hypoventilation Syndrome? Causes, Types, Treatment

Medically Reviewed by Dr. Sony Sherpa, (MBBS) - October 23, 2026

Fact Checked and Edited by Dr. Rae Osborn, Ph.D. - October 23, 2026

Introduction

Central Hypoventilation Syndrome is a rare and potentially life-threatening disorder in which automatic control of breathing, especially during sleep, is impaired or fails entirely.

CHS is extremely rare. One in 148,000 to 200,000 live births is the estimated incidence of the congenital form, known as Congenital Central Hypoventilation Syndrome or CCHS. Several public figures have supported efforts to raise awareness of congenital central hypoventilation syndrome. According to the CCHS Foundation's 2020 Annual Report, celebrities including Jonah Hill, Henry Winkler, Charlize Theron, Ariel Winter, and Leighton Meester used their voices and social media platforms to support International CCHS Day. These efforts have helped raise awareness of CCHS and support individuals and families affected by the condition.

Since some cases remain undiagnosed, the true prevalence of CHS is likely higher, though exact numbers remain unknown. Historically, only a few hundred cases were documented globally in the early 2000s. As awareness, genetic testing, and ventilatory support have improved, more cases, including milder or late-onset variants, have been identified, but CHS remains a rare disease.

What Is Central Hypoventilation Syndrome?

Normally, breathing is regulated automatically by the brainstem without conscious thought. In CHS, the signals that tell the respiratory muscles to breathe regularly are inadequate or absent. As a result, people may breathe too shallowly, too slowly, or stop breathing altogether, particularly while sleeping. In severe cases, symptoms may also occur while awake. The lack of adequate ventilation causes insufficient oxygen intake and buildup of carbon dioxide, threatening vital organ function.

Because CHS affects involuntary control of breathing, many normal functions such as heart rate regulation, response to low oxygen or high carbon dioxide, blood pressure, and body temperature may all be disrupted. This makes CHS not just a sleep breathing disorder, but a disorder of the autonomic nervous system.

To fully understand CHS, it helps to understand how normal breathing works and how CHS affects this process.

How Breathing Works

Breathing is ordinarily an automatic process. This involuntary control is mediated by the autonomic nervous system and certain centers in the brainstem. Respiratory muscles, especially the diaphragm and intercostal muscles, contract and relax rhythmically to draw air in and push air out, maintaining exchange of oxygen and carbon dioxide between the lungs and bloodstream.

This automatic drive ensures that even during sleep, breathing continues seamlessly, maintaining oxygen levels, eliminating carbon dioxide, regulating blood pH, and supporting vital organ function.

Role of the Brainstem and Autonomic Nervous System

The brainstem, particularly the medulla, controls breathing rhythms automatically. Specialized neuronal circuits monitor blood gas levels and adjust the rate and depth of breathing. The autonomic nervous system handles involuntary functions such as breathing, heart rate, blood pressure, body temperature, and digestion.

Thus, even when a person is asleep, anesthetized, or unconscious, breathing continues because of this automatic control.

Chemoreceptors and CO₂/O₂ Monitoring

Chemoreceptors in the brainstem and peripheral tissues detect changes in carbon dioxide and oxygen in the blood. When CO₂ rises or oxygen drops, chemoreceptors signal the body to increase breathing rate and depth. This feedback prevents carbon dioxide accumulation and maintains oxygen levels. In healthy people, a small rise in CO₂ or drop in oxygen triggers an immediate increase in ventilation, even during sleep.

What Goes Wrong in CHS?

In CHS, the brainstem’s ability to sense changes in CO₂ and oxygen, or to send appropriate signals to breathing muscles, is impaired. As a result:

• The chemoreceptors fail to detect high CO₂ or low oxygen, or the detection does not lead to an adequate drive to breathe.
• Automatic respiratory drive is blunted or lost, particularly during sleep.
• Ventilatory response to high CO₂ or low oxygen is diminished or absent.
• In severe cases, breathing may stop when asleep, unconscious, or under sedation unless supported mechanically.

In simple terms, the body’s automatic control of breathing is disrupted.

Types, Causes, and Risk Factors for Central Hypoventilation Syndrome

CHS can be broadly categorized into congenital and acquired forms, each with distinct causes, onset patterns, and associated risk factors. Understanding these differences is essential for diagnosis, management, and genetic counseling.

Congenital Central Hypoventilation Syndrome (CCHS)

Other names

Congenital CHS has been referred to by several terms in medical literature, reflecting its rarity and historical context. Common names include:

• Ondine’s Curse – A historical term inspired by a mythological story, though it is largely symbolic rather than scientifically descriptive.
• Congenital Central Alveolar Hypoventilation Syndrome – Emphasizes the primary issue of hypoventilation at the alveolar level.
• Haddad Syndrome – Used when CCHS co-occurs with Hirschsprung disease.

Genetic cause: PARMs and NPARMs

CCHS is primarily caused by mutations in the PHOX2B gene, which plays a crucial role in the development of the autonomic nervous system. The types of mutations are:

• PARMs (Polyalanine Repeat Mutations) – The most common mutation type, characterized by abnormal expansion of alanine repeats in the PHOX2B gene. The number of repeats correlates with severity; larger expansions often lead to more pronounced hypoventilation and associated disorders.
• NPARMs (Non-Polyalanine Repeat Mutations) – These are less common and include missense, nonsense, or frameshift mutations that disrupt normal gene function. NPARMs are often associated with more complex or syndromic CCHS phenotypes, but clinical severity varies depending on the specific variant and its location.

PHOX2B mutations affect neural crest-derived cells and disrupt the automatic control of breathing, particularly during sleep. This defect reduces the responsiveness to elevated CO₂ or low O₂ levels, leading to hypoventilation.

Onset of symptoms

• Classic CCHS – Symptoms typically appear at birth or in the neonatal period. Infants may exhibit apnea, cyanosis, poor feeding (in some cases), and hypoventilation during sleep.
• Late-onset CCHS – Some people may not show signs until childhood or even adulthood, usually with milder hypoventilation or autonomic symptoms. Late-onset forms may be triggered by respiratory illness, anesthesia, or sedative medications.

Associated disorders

Due to the impact of PHOX2B mutations on neural crest-derived tissues, CCHS can co-occur with other conditions:

• Hirschsprung Disease (Haddad Syndrome) – Intestinal motility disorder caused by absence of enteric ganglion cells; occurs in a subset of patients with CCHS.
• Autonomic Nervous System Dysregulation (ANSD) – Can manifest as heart rate variability reduction, abnormal blood pressure responses, temperature dysregulation, impaired pupillary reflex, and gastrointestinal motility issues.
• Risk of Neural Crest-Derived Tumors – Increased susceptibility to neuroblastomas, ganglioneuromas, and other tumors.
• Additional features – Neurodevelopmental delays, impaired pain perception, and eye abnormalities may also be observed.

Acquired Central Hypoventilation Syndrome (ACHS)

Unlike congenital forms, ACHS can develop later in life due to damage to the brainstem or autonomic pathways controlling breathing. It may be sudden or progressive, depending on the underlying cause.

Causes

• Brainstem stroke – Infarction in the medulla or pons can impair central respiratory control.
• Tumors – Space-occupying lesions in the brainstem or nearby regions may compress respiratory centers or autonomic pathways.
• Trauma or surgery – Head or neck injuries, neurosurgical procedures (to remove brain tumors), or spinal cord trauma can affect brainstem or phrenic nerve function.
• Neurodegenerative conditions – Disorders such as multiple system atrophy may gradually impair automatic breathing.
• Severe infections and inflammation – Encephalitis or meningitis can damage neural circuits controlling ventilation.

Risk Factors

• History of cerebrovascular disease or brain injury
• Prior neurosurgery or trauma involving the brainstem
• Neurodegenerative disease affecting autonomic control
• Severe CNS infections
• Brainstem tumors

In ACHS, unlike CCHS, genetic testing is typically not diagnostic, and imaging is crucial to identify structural or acquired causes.

Symptoms

Symptoms of CHS stem mainly from failure of automatic respiratory control and may include broader autonomic dysfunction. Severity varies depending on subtype, mutation, or underlying insult.

Primary Symptoms

Core respiratory symptoms include:

• Shallow or slow breathing, especially during sleep
• Episodes of apnea, where breathing may pause for seconds or longer
• Cyanosis, a bluish discoloration of skin, lips, or extremities
• Morning headaches due to nighttime hypoventilation and CO₂ build-up
• Excessive daytime sleepiness and fatigue

Additional symptoms may include changes in heart rate, blood pressure instability, temperature dysregulation, gastrointestinal dysfunction, and eye abnormalities.

In Children

Infants and young children may present with:

• Poor feeding due to inefficient breathing and gastrointestinal issues
• Weak cry from insufficient respiratory drive
• Cyanosis during sleep or apnea episodes
• Autonomic and developmental issues such as abnormal pupillary reflex, temperature regulation problems, impaired gut motility, and heart rate irregularities
• Developmental delays, if hypoxia is prolonged

Infants often require careful monitoring, ventilatory support, and multiple specialist involvement.

In Adults

Late-onset or milder CHS may present with:

• Fatigue and daytime sleepiness
• Cognitive impairment
• Non-restorative sleep
• Exercise-related intolerance with minimal activity
• Chronic autonomic symptoms, including heart rate variability

Milder or late-onset CHS may be misdiagnosed as sleep apnea or other conditions.

Complications

If untreated, CHS can lead to:

• Chronic respiratory failure due to persistent inadequate ventilation
• Heart problems and pulmonary hypertension from low oxygen and high CO₂
• Organ damage from hypoxia may affect the brain, kidneys, liver, and heart
• Arrhythmias due to autonomic dysfunction
• Sudden death, especially during sleep. There is speculation that some cases of sudden infant death syndrome (SIDS) may be due to CCHS.
• Complications from associated disorders, such as bowel obstruction or tumors

CHS can be life-threatening without proper management.

Mortality and Survival Rates

Advances in ventilatory support have significantly improved survival for individuals with CCHS, although early mortality remains a key risk. A 2026 European registry study of children and young adults with genetically confirmed CCHS reported an overall mortality rate of 14%, with young children accounting for the majority of the deaths. Consequently, while the 25-year survival probability for patients with isolated CCHS was 89%, those with co-occurring Hirschsprung disease had only a 26% survival probability. These outcomes highlight how co-occurring conditions and severe autonomic dysfunction influence long-term prognosis.

Diagnosis

Accurate and timely diagnosis of Central Hypoventilation Syndrome, particularly Congenital Central Hypoventilation Syndrome, is essential for preventing life-threatening complications and guiding treatment. Diagnosis combines clinical evaluation, specialized tests, and genetic confirmation.

Diagnostic Criteria for CCHS

CCHS is primarily diagnosed based on:

• Clinical features – Persistent hypoventilation during sleep, blunted response to elevated CO₂ or low O₂, and autonomic nervous system dysfunction.
• Genetic confirmation – Identification of a pathogenic PHOX2B mutation (PARMs or NPARMs) through molecular testing.
• Exclusion of acquired causes – Ruling out structural, traumatic, infectious, or neurodegenerative conditions that may cause similar hypoventilation.

A definitive diagnosis usually requires a combination of clinical observation and genetic testing.

Clinical Evaluation

• Symptoms and history

  • Detailed assessment of breathing patterns, cyanosis, fatigue, daytime sleepiness, feeding difficulties (in infants), and developmental delays.
  • Family history may reveal similar breathing or autonomic issues.
  • Review of sleep patterns, observed apnea episodes, and response to sedatives or anesthetics.

• Sleep pattern observation

  • Continuous monitoring of breathing during sleep (polysomnography) to detect hypoventilation, pauses, or shallow breathing.
  • Observations are especially important in newborns and infants to detect nocturnal hypoventilation.

Tests

Several specialized investigations are used to confirm the diagnosis and assess severity:

• Polysomnography (sleep study) – Measures oxygen saturation, CO₂ levels, airflow, and respiratory effort during sleep. It identifies hypoventilation and apnea episodes.
• Arterial Blood Gases – Evaluate oxygen (PaO₂) and carbon dioxide (PaCO₂) levels, providing direct evidence of hypoventilation. PaCO₂ is the main blood-gas measurement for showing hypoventilation, while PaO₂ provides information about oxygenation.
• End-Tidal CO₂ Monitoring – Non-invasive measurement of CO₂ at the end of exhalation, useful for continuous monitoring at home or in the hospital.
• Genetic Testing for PHOX2B – Confirms CCHS by identifying PARMs or NPARMs mutations. This is the gold standard for diagnosis, in addition to clinical symptoms.
• Imaging (MRI/CT) – Essential in Acquired Central Hypoventilation Syndrome (ACHS) to detect brainstem lesions, tumors, infarcts, or structural abnormalities.

Central Hypoventilation Syndrome: Differential Diagnosis

CHS shares overlapping features with several other conditions, so careful differentiation is necessary. Some conditions may occur concurrently with CHS and should be considered as associated disorders.

Key conditions to differentiate include:

• Central Hypoventilation Syndrome vs. Obstructive Sleep Apnea (OSA) vs. Obesity Hypoventilation Syndrome (OHS)

  • CHS – Impaired central control of breathing; hypoventilation occurs primarily during sleep; blunted response to CO₂; autonomic dysfunction often present.
  • OSA – Obstruction of the upper airway during sleep; respiratory drive intact; repeated arousals; commonly associated with obesity.
  • OHS – Hypoventilation secondary to obesity; respiratory drive may be partially reduced; chronic CO₂ retention; occurs in adults with BMI ≥30.

• ROHHAD syndrome

Rapid-onset obesity with hypothalamic, autonomic, and respiratory dysregulation. Shares features of autonomic dysfunction and sleep-related hypoventilation, but onset is typically after infancy.

• Prader-Willi Syndrome (PWS)

Genetic disorder with hypotonia, hyperphagia, obesity, and central or obstructive sleep apnea. Hypoventilation may be present but usually with additional endocrinologic and metabolic features.

• Chiari Malformation

Structural brain abnormality with downward herniation of cerebellar tonsils through the foramen magnum into the upper spinal canal, which may disrupt brainstem respiratory centers.

• Achondroplasia

Skeletal dysplasia that can contribute to sleep-related breathing disorders due to craniofacial and airway anatomy, though central hypoventilation is uncommon.

• Mitochondrial Disorders

Rare genetic conditions affecting cellular energy metabolism; may cause multisystem involvement and may affect central respiratory control

• Familial Dysautonomia

Inherited disorder affecting the autonomic nervous system, potentially causing irregular breathing, blood pressure fluctuations, and impaired response to hypoxia or hypercapnia.

Treatment Options

There is no cure; management focuses on supporting ventilation, monitoring, treating associated conditions, and preventing complications. Multidisciplinary care is essential.

Ventilatory Support

• Positive pressure ventilation via ventilator, often through tracheostomy in infants and young children
• Non-invasive ventilation using mask-based devices for older children or adults
• Diaphragm pacing with phrenic nerve stimulation to rhythmically contract the diaphragm and reduce dependence on mechanical ventilation

Monitoring

• Home oxygen and CO₂ monitoring
• Regular sleep studies
• Continuous care by a multidisciplinary team
• Regular screening for neural crest-derived tumors

Other Supportive Treatments

• Gastrointestinal management for motility issues
• Cardiac care for arrhythmias or autonomic instability
• Ophthalmologic care for pupillary abnormalities
• Neurodevelopmental and cognitive support
• Psychosocial support for lifestyle adaptations

Treatment aims to manage symptoms, support breathing, prevent complications, and maximize quality of life.

Living With CHS

Prognosis and Life Expectancy

Advances in ventilatory support and multidisciplinary care have improved outcomes. Many people with CCHS can grow into adulthood, attend school, work, and lead active lives. Prognosis depends on severity of respiratory impairment, presence of associated conditions, and timeliness of treatment. With proper management, many patients can achieve prolonged survival and a near-normal lifespan.

Lifestyle and Supportive Care

• Vaccinations to reduce respiratory infection risk, since such infections can be important in children with CCHS
• Maintain healthy sleep hygiene and follow the prescribed nighttime ventilatory support and monitoring
• Maintain prescribed ventilatory support during acute illness and after sedation or anesthesia
• Transitioning from pediatric to adult care with a multidisciplinary team and transfer of all records
• Travel precautions with needed technological aids (portable ventilators, alarms)
• Avoid respiratory depressants such as strong prescription pain relievers and sedatives
• Regular follow-up with healthcare providers
• Education, psychological, and social support

With proper care, patients with CHS can live active, fulfilling lives despite the chronic nature of the condition.

Frequently Asked Questions

• Can someone have central hypoventilation syndrome without having symptoms during the day?

Yes. A person with congenital central hypoventilation syndrome can have no obvious daytime breathing difficulties because hypoventilation is typically more severe during sleep. However, some patients can also experience hypoventilation while awake.

• Is central hypoventilation syndrome hereditary?

Congenital central hypoventilation syndrome can be inherited through an autosomal dominant genetic pattern involving the PHOX2B gene. This means that if a parent carries the disease-causing variant, each child has a 50% chance of inheriting it. However, more than 90% of cases result from new (de novo) genetic variants rather than inheritance from a parent.

In contrast, acquired central hypoventilation develops following an underlying neurological injury or condition, such as brainstem trauma, stroke, or inflammation, rather than being inherited.

• If a child has CCHS, can a parent also have the PHOX2B mutation?

Yes. A parent of a child with CCHS can also carry the disease-causing PHOX2B variant, even without noticeable symptoms. This may occur when the variant is present in all cells (constitutive variant) but has reduced penetrance, meaning the parent may not develop typical CCHS symptoms. Alternatively, the variant may be present in only some of the parent's cells (somatic mosaicism) or in their reproductive cells (germline mosaicism), even when it is not detected in their blood.

• Can a person with CCHS have children?

Yes. A person with CCHS can have children. However, pregnancy requires careful medical planning because breathing and ventilation may change. Genetic counseling can help prospective parents understand the risk of passing on the PHOX2B gene variant to their children.

• Can central hypoventilation syndrome be detected before birth?

Yes. Congenital central hypoventilation syndrome can be detected before birth through prenatal genetic testing when the disease-causing PHOX2B variant is known in the family.

• Why are carbon dioxide levels monitored in central hypoventilation syndrome, not just oxygen levels?

In central hypoventilation syndrome, carbon dioxide levels are monitored because oxygen levels alone cannot show whether breathing is adequate. Carbon dioxide can build up even when oxygen levels appear normal, and people with the condition may not recognize this change.

• Why can someone with central hypoventilation syndrome have low oxygen without feeling short of breath? 

People with central hypoventilation syndrome may have low oxygen levels without feeling short of breath because the brain’s automatic breathing response to rising carbon dioxide is impaired. Research also shows that breathlessness can be mild or absent in some people with CCHS, although responses vary between individuals.

• When is noninvasive ventilation used for central hypoventilation syndrome?

Noninvasive ventilation may be used in central hypoventilation syndrome for breathing through a mask, particularly in patients who need support only during sleep. It may also be an option for selected patients transitioning from a tracheostomy depending on age, airway anatomy, and ventilation needs.

• Does central hypoventilation syndrome require lifelong treatment?

Central hypoventilation syndrome may require long-term or lifelong ventilatory support, depending on its cause. Congenital central hypoventilation syndrome generally requires lifelong support, whereas the acquired form may improve if the underlying cause is reversible. However, lifelong support may be necessary if impaired breathing control persists.

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