There is no proof that KLS has any known genetics. There is also no protein or antibodies available for a positive diagnosis for Kleine-Levin Syndrome.

So what causes KLS? It is very difficult to diagnose because there are no positive symptoms. In order to diagnose KLS a doctor must rule out other conditions that mimic the symptoms. Patients are usually treated for a sleeping disorder because of a symptom called hypersomnia.

There are other disorders that mimic KLS symptoms and can be diagnosed by an MRI. MRI’s can also diagnose problems that are caused by lesions, tumors and inflammation. MS or Multiple Sclerosis also has neurological components that mimic KLS.

These patients are also referred to an endocrinologist to check for problems like diabetes and hypothyroidism as well as other metabolic problems, and are often misdiagnosed with psychiatric disorders

The misdiagnosed disorders of KLS seem to come about because of the periods of somnolence, hyperphagia and withdrawal that can mimic sever depression and the brief periods of high energy following these episodes that people experience. Because of the mimicked episodes of KLS, some patients are diagnosed with bipolar disorder.
Narcolepsy and Kluver-Bucy syndrome can mimic primary psychiatric disorders. So before a final diagnosis can be made; all the other possibilities of these symptoms must be excluded and the cluster of symptoms must fit with the commonly observed in KLS patients.