Final answer:
Genetic factors are observed in up to 100% of patients with narcolepsy, often involving a human leukocyte antigen subtype. Cataplexy is a common symptom, and while psychomotor stimulant drugs are used for treatment, new therapies are envisaged that target the hypocretin system.
Step-by-step explanation:
Narcolepsy and Its Genetic Link
In 90 to 100% of patients with narcolepsy, a condition marked by an uncontrollable urge to sleep at inappropriate times, genetic factors are observed. The primary genetic feature associated with narcolepsy is a particular human leukocyte antigen (HLA) subtype. A strong genetic association is found with the HLA subtype DQB1*0602, which is present in most individuals with narcolepsy. The condition often involves cataplexy, or sudden muscle weakness triggered by emotions such as laughter or surprise, mimicking muscle paralysis during REM sleep. Treatments for narcolepsy often include psychomotor stimulant drugs such as amphetamines, which increase neural activity. However, these do not target the deficiency of the signaling molecule hypocretin, which is believed to be responsible for the symptoms. Advances in treatment are expected to focus on targeting the hypocretin system to improve symptom management. Despite narcolepsy's substantial impact on a person's daily life and safety, available treatments can vary in effect. Case studies, like McCarty's 2010 report, highlight unique presentations of the disease and the mixed success of treatment regimens, emphasizing the importance of individualized approaches to managing symptoms.