Narcolepsy is a sleep disorder that causes daytime sleepiness. Some cases may be linked to genes that influence the levels of a brain hormone called hypocretin.

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Narcolepsy is a neurological disorder where a person may feel groggy or suddenly fall asleep during the day. This disorder makes it difficult to stay alert and perform work, school, or other necessary tasks.

Narcolepsy may also cause muscle weakness and make it hard to get into deep or restful sleep.

While much is still unknown about the cause of narcolepsy, researchers believe there’s a genetic component in some cases.

Keep reading to find out more about the genetics of narcolepsy, what the risk factors are, and how doctors treat this condition.

Here’s more detailed information about narcolepsy.

Experts believe there’s a genetic component to type 1 narcolepsy (NT1), which is narcolepsy with cataplexy, or muscle weakness.

While genes do not directly cause it, most people with NT1 carry the human leukocyte antigen (HLA) gene HLA-DQB1*06:02.

People with NT1 have lower levels of hypocretin in the brain. This protein helps regulate sleep cycles, and low levels lead to NT1.

The HLA gene, which researchers estimate is present in 95% of people with NT1, may increase the possibility of immune system issues, leading to a hypocretin deficiency.

Less is known about the genetics of type 2 narcolepsy (NT2). NT2 is narcolepsy without cataplexy. People with NT2 have typical levels of hypocretin in the brain, but research has uncovered that 30–50% of people with NT2 may also carry the HLA-DQB1*06:02 gene.

That said, some 20% of people who carry the HLA gene do not have narcolepsy.

Genetics may only be one piece of the puzzle, with environmental factors also playing a key role.

The root cause of narcolepsy is largely unknown.

Most of the time, narcolepsy happens at random in people with no family history.

What is known is that people with NT1 have low levels of hypocretin, which may occur from various triggers.

Triggers for narcolepsy may include:

Some studies have found an association between narcolepsy in children and the vaccine Pandemrix for H1N1 (swine flu) in Europe. The chances are very low, however, and the vaccine is no longer used.

Family history may slightly increase a person’s risk of narcolepsy.

Researchers share that 1–2% of first degree relatives of a person with NT1 go on to develop the condition. This means their risk level is 10–40 times higher than those without a family history.

There are no sex differences in who’s affected by narcolepsy. Symptoms often appear when a person is 7–25 years old.

Your risk of developing narcolepsy may also be higher after:

Treatment for narcolepsy depends on the person and their symptoms. Treatments aim to improve symptoms.

Your doctor may suggest lifestyle strategies to improve your sleep hygiene. This may include things like:

  • taking frequent naps
  • avoiding caffeine in the evenings
  • creating a bedtime routine, for example:
    • taking a bath to relax
    • having a strict bedtime every day of the week
    • sleeping in a dark, cool, and calm environment

Certain medications may also help, including:

  • modafinil (Provigil) to stimulate the brain and help with wakefulness
  • sodium oxybate (Xyrem) to address loss of muscle control and help with nighttime sleep
  • pitolisant (Wakix) to help with daytime sleepiness
  • solriamfetol (Sunosi) to help with alertness
  • antidepressants, such as venlafaxine, fluoxetine, and amitriptyline, to address loss of muscle control, hallucinations, and sleep paralysis

There is no cure for narcolepsy, so it can be difficult to live with this chronic condition. However, working closely with your doctor on a treatment plan can help you better manage your sleep and wakefulness during the daytime.

Does a person with narcolepsy sleep most of the day?

No. A person with narcolepsy may sleep the same amount of time as a person who doesn’t have the condition. However, these sleep cycles do not allow for restful sleep.

Can a person with narcolepsy drive a car?

Most people with narcolepsy can drive legally in the United States. They may need to make modifications, like driving shorter trips or ensuring they are well rested before doing so.

Where can I find support?

Organizations that provide education and support for narcolepsy include:

Genetics may influence narcolepsy. But in most people with the condition, it happens randomly with no family history.

If you’re experiencing grogginess during the day and think you may have narcolepsy or some other sleep disorder, make an appointment with a doctor.

A sleep study can help give you an accurate diagnosis, and the appropriate treatment can improve your quality of life.