Is Narcolepsy Hereditary?
Is narcolepsy hereditary? This is one question that researchers are trying to answer, since the day narcolepsy surfaced. Narcolepsy, in laymen's terms, is sudden sleep attacks at inappropriate times and places, like while eating, driving or in the middle of a conversation. This is often triggered by intense emotions like sadness, surprise, fear, and happiness. Narcolepsy is defined as a neurological condition most characterized by excessive daytime sleepiness or EDS. The patient of this disease, most likely, experiences disturbed nocturnal sleep, baffled with insomnia, and disorder of rapid eye movement sleep (REM).
One of the symptoms of narcolepsy is inordinate daytime sleepiness, so excessive that one time the person suffering for narcolepsy is talking to somebody and another second he is slumped on the table snoring. Other distinct symptoms of this disorder are cataplexy (sudden loss of muscle tone), hypnagogic hallucinations (vivid dreaming), sleep paralysis and automatic behavior.
What causes Narcolepsy is still a mystery shrouded behind clouds. The scientists have discovered conditions that may increase an individual's risk of having the disorder. Specifically, there appears to be a strong link between narcoleptic people and certain genetic conditions.
One of the factors that may predispose an individual to narcolepsy involves an area of chromosome termed as chromosome 6, also known as the HLA complex. The human leukocyte antigen (HLA) system is the name of the human major histocompatibility complex. This group of genes resides on chromosome 6 and encodes cell surface antigen, presenting proteins and many other genes.
HLA complex variations increase the risk of an auto-immune response to protein producing neurons in the brain. The protein produced, termed hypocretin or orexin is responsible for controlling the appetite and sleep patterns. Individuals with narcolepsy often have reduced numbers of these protein producing neurons in the brain. Narcoleptic people have little or very few levels and sometimes absence of hypocretin neurons and neurotransmitters.
Several studies have shown that genetics may have something to do with the development of this disorder. The defective gene could be transmitted through heredity in an autosomal dominant fashion.
It means a person has higher risk of developing narcolepsy if a close relative is affected with the disorder. But experts are hitting into another angle, which is autoimmune response where the body's defense system attacks its own cells. In this scenario, the defense system, mistakenly takes hypocretin cells as a foreign body and destroy it. Now, still it is quite possible that this problem of autoimmunity is itself hereditary, thus making narcolepsy hereditary as well.
Other contributing factors that can damage the hypocretin are viral infections like mumps and measles, brain injury, stress and changes in hormone. The last factor also explains why most initial narcolepsy attacks happen during puberty.
Finally, answering the question, is Narcolepsy hereditary, still remain an enigma. While studies have confirmed that 5% to 10% of people suffering from Narcolepsy have hereditary condition, but still the topic is open to be debated with proper documents of research.