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Sleep apnea is a common sleep disorder that causes a person to repeatedly stop breathing as they sleep. As a result of these breathing difficulties, people with sleep apnea often snore and may experience daytime tiredness, morning headaches, irritability, and difficulty concentrating.
Sleep apnea increases a person’s risk for other health problems, like heart attack and stroke. Because of its impact, people are often curious about what causes sleep apnea and if genetics play a role.
Is Sleep Apnea Genetic?
Researchers have identified genetic factors that contribute to a person’s likelihood of developing obstructive sleep apnea (OSA), a type of sleep apnea in which lapses in breathing are caused by physical airway blockages. By contrast, central sleep apnea, a disorder that involves lapses in breathing due to brainstem signaling issues, appears to be largely caused by other, non-genetic factors .
Studies show that people face a greater risk of developing OSA when they have a close family member with the disorder. Experts estimate that about 40% of differences in the number of times people stop breathing (Apnea Hypopnea Index or AHI) as they sleep is due to genetics.
Researchers hypothesize that there are multiple ways genetics may predispose a person to OSA:
- Body Fat Amount and Distribution: Genes impact body weight and where fat is located on your body, both of which influence whether or not a person develops OSA. People who are obese are more than 10 times as likely to have OSA.
- Face Anatomy: Genes greatly affect the shape of a person’s face and skull, including skull width, nose width and length, and facial depth. The size and shape of a person’s nose, along with the placement of the jaw and other bones, impact how wide the airway is and how easily it can become blocked.
- Breathing Control: Research on genes and breath control is lacking, but experts suspect genetics could influence the muscles and neural signals involved in breathing. How a person breathes may influence their likelihood of experiencing sleep apnea.
- Sleep and Circadian Rhythm: A person’s genes influence their innate sleep schedule, as well as how well they sleep and whether or not they have other sleep disorders. Researchers have called for future studies to examine how genetics affect sleep patterns as they relate to OSA.
Although researchers have been studying the genetics of sleep apnea for more than 20 years, relatively little is known about the specific genes involved with sleep-disordered breathing. Much more research is needed, but as of now, researchers have found evidence suggesting the following genes may be related to intermittent hypoxia or involved in OSA :
- Angiopoietin-2 gene (ANGPT2)
- −308G/A polymorphism of the tumor necrosis factor-α (TNFα)
- Prostaglandin E2 receptor EP3 subtype (PTGER3)
- Lysophosphatidic acid receptor 1 (LPAR1)
- G-protein receptor gene (GPR83)
- β-arrestin 1 gene (ARRB1)
- Dopamine receptor D1 encoding gene (DRD1)
- Serotonin receptor encoding gene (HTR2A)
More research is needed to confirm, but genetic factors involved in OSA could partially explain why the disorder affects people of different races differently. Genetics could also help explain why OSA is connected to so many other conditions. Related research is in the early stages, but researchers have found overlap in genes associated with both OSA and high triglyceride levels .
Causes of Sleep Apnea
The causes and risk factors for sleep apnea vary depending on the type of sleep apnea and the age at which it develops.
Obstructive Sleep Apnea
Repeated obstructions of the upper airway during sleep cause OSA. Multiple factors increase a person’s risk of developing the disorder:
- Obesity: A 10% increase in body weight makes a person six times as likely to develop moderate to severe OSA. By contrast, losing 10% of your body weight can reduce the number of lapses in breathing per hour by 26%.
- Body Type: Where a person carries weight can increase their risk of OSA. Those with a larger neck or a larger abdomen face a greater risk.
- Face Anatomy: A person’s face shape, as well as the placement of certain bones in the head and jaw, can result in a narrow airway and an increased risk of OSA.
- Sex: Men are more likely to develop OSA throughout young and middle adulthood. Once women experience menopause, however, they are equally as likely to have OSA. Among men and women with a similar body mass index, men tend to experience more severe symptoms.
- Age: OSA becomes more common as people age. For example, research suggests that 10% of men between 30 and 40 have OSA, while 30% of men over 80 have the disorder. This increased risk could be the result of less time spent in deep sleep, which tends to occur naturally with age.
- Race and Ethnicity: Studies have found people of Black, Hispanic, Chinese, and American Indian descent face a slightly higher OSA risk. These differences in risk might be due to differences in the anatomy of the face.
Central Sleep Apnea
Central sleep apnea (CSA) is caused by the brainstem failing to properly regulate breathing during sleep. Although CSA also involves lapses in breathing during sleep, its causes and risk factors are very different from those for OSA:
- Congestive Heart Failure: Experiencing heart failure often leads to physiological changes that make a person more likely to experience CSA. These changes include increased sensitivity in carotid artery receptors, increased pressure in blood vessels found in the lungs, increased sensitivity to changes in blood carbon dioxide levels, and longer blood circulation times.
- High Altitudes: Even healthy people with no history of CSA face an increased risk when they travel to high altitudes measuring 3,000 meters or more above sea level. Particularly sensitive people might experience symptoms at altitudes lower than that, especially if they stay there for an extended period of time.
- Opioid Use: Over half of chronic opioid users experience CSA symptoms as they sleep, and the severity of symptoms corresponds to the dose of opioids taken. This high rate is likely due to the effect opioids have on the central nervous system.
- OSA Treatment: Some people experience treatment emergent or complex sleep apnea, in which CSA symptoms arise during continuous positive airway pressure (CPAP) treatment for OSA. This type of CSA is controversial, with experts disagreeing about what causes it and how to treat it. Some say people with complex sleep apnea should continue using CPAP therapy and CSA symptoms will stop with time. Others argue that CPAP should be discontinued in favor of other treatment modalities.
Less commonly, CSA is associated with kidney failure or has no known cause, in which case it is called idiopathic central sleep apnea . Experts continue to research and try to understand how CSA develops in idiopathic cases.
Child Sleep Apnea
Like adults, children can experience both obstructive sleep apnea and central sleep apnea. Several factors increase a child’s risk of developing OSA :
- Enlarged tonsils or adenoids
- Excessive nasal congestion
- Skull or face abnormalities
- Sedatives or opioid medications
- Certain congenital disorders, like Down syndrome, cerebral palsy, and Prader-Willi syndrome
Obesity is currently the most common risk factor for childhood OSA. As many as 60% of obese children have OSA, and the rate of OSA in children can be expected to grow as obesity rates increase.
CSA is very rare in children and has not been widely studied. Existing research shows that CSA in children is associated with various neurological disorders, including:
- Arnold-Chiari malformation
- Prader-Willi syndrome
- Down syndrome
- Other genetic diseases
Sleep apnea is more common in infants under 1 year of age — particularly those born prematurely or those with other risk factors — due to their still-developing sleep-wake cycle, respiratory drive, and physical airway structure. In some cases, the condition that causes sleep apnea in an infant may be inherited .
When to Talk to Your Doctor
If you or your child show signs of sleep apnea, make an appointment with your doctor. Symptoms of sleep apnea include snoring, daytime tiredness, morning headaches, trouble concentrating, and irritability. A bed partner may observe gasping, choking, and noticeable lapses in breathing. Children show similar symptoms, but may also experience night sweats, wetting the bed, mouth breathing, and hyperactivity.
Your doctor can ask questions to determine if sleep apnea might be the disorder you are facing and, if so, refer you to a sleep specialist for further testing. By diagnosing and treating sleep apnea, people can improve their symptoms and reduce their risk of other associated disorders.