PET Study of Microglial Activation in Kleine-Levin Syndrome.

OBJECTIVES: Kleine-Levin syndrome (KLS) is a rare recurrent hypersomnolence disorder associated with cognitive and behavioral disturbances, of unknown origin, but inflammatory mechanisms could be involved. We aimed to explore in vivo microglia activation using [18F]DPA-714 PET imaging in patients with KLS compared with controls, and during symptomatic vs asymptomatic periods. METHODS: Patients with KLS and controls underwent a standardized clinical evaluation and PET imaging, using a radiolabeled ligand specific to the 18 kDa translocator protein. Images were processed on the PMOD (peripheral module) interface using a standard uptake value (SUV). Five regions of interest (ROIs) were analyzed: hypothalamus, thalamus, frontal area, cerebellum, and whole brain. SUV ratios (SUVr) were calculated by normalizing SUV with cerebellum uptake. RESULTS: Images of 17 consecutive patients with KLS (7 during episodes, 10 out of episodes) and 14 controls were analyzed. We found no SUV/SUVr difference between KLS and controls, between patients in and out episodes in all ROIs, and no correlation between SUVr and episode duration at the time of PET scan. No association was found between SUVr and sex, disease duration, or orexin levels. DISCUSSION: Our findings do not support the presence of neuroinflammation in KLS. Further research is needed to identify relevant biomarkers in KLS.

Improvement in non-24-h sleep-wake rhythm disorder in a sighted individual treated with a melatonin receptor agonist.

Non-24-hour sleep-wake rhythm disorder (N24SWD) typically presents in patients with visual impairments that disrupt the ability to entrain to the 24 hour solar cycle. We discuss a 43 year old sighted man who presented with periodic daytime hypersomnia and nighttime insomnia, occasionally leading to <3 hours of sleep per day. Previous polysomnography showed an apnea hypopnea index of 6.2 events per hour. A sleep log of 3 months showed irregular time of sleep onset, and an average of 3 hours of sleep per day. Wrist actigraphy confirmed N24SWD. A trial of tasimelteon 20 mg/day resulting in improved daytime hypersomnia (pre-Epworth Sleepiness Scale (ESS) = 21/24, post-ESS = 5/24; a score of > 10/24 is considered sleepy). Follow-up actigraphy showed marked resolution of phase delay with an average of five hours of sleep. The case demonstrates that tasimelteon is a possible treatment for N24SWD in sighted individuals.

Apparent resolution of hypersomnia episodes in two patients with Kleine-Levin syndrome following treatment with the melatonin receptor agonist ramelteon.

Kleine-Levin syndrome (KLS) is a rare disorder characterized by episodic bouts of severe hypersomnia associated with cognitive and behavioral abnormalities and normal alertness and functioning in between episodes. The pathophysiology is unclear but may involve neurotransmitter abnormalities, hypothalamic/thalamic dysfunction, viral/autoimmune etiology, or circadian abnormalities. No single treatment has been shown to be reliably efficacious; lithium has demonstrated the most consistent efficacy, although many do not respond and its use is limited by side effects. Due to the evidence of circadian involvement, we hypothesized that strengthening circadian signals may ameliorate symptoms. Ramelteon is a potent melatonin receptor agonist. In this report, two patients with KLS are described with apparent resolution of hypersomnia episodes following ramelteon initiation. CITATION: Dominguez D, Rudock R, Tomko S, Pathak S, Mignot E, Licis A. Apparent resolution of hypersomnia episodes in two patients with Kleine-Levin syndrome following treatment with the melatonin receptor agonist ramelteon. J Clin Sleep Med. 2024;20(4):657-662.

Idiopathic Hypersomnia and Kleine-Levin Syndrome: Primary Disorders of Hypersomnolence Beyond Narcolepsy.

Daytime sleepiness is common amongst children and adolescents. Inadequate sleep duration, inappropriate school start times, and the delay in sleep phase of adolescence may all contribute. Nocturnal sleep disruption due to sleep disorders such as obstructive sleep apnea or restless legs syndrome/periodic limb movement disorder may also lead to daytime sleepiness. Profound sleepiness however, when occurring in the setting of adequate sleep duration, is rare amongst children and adolescents and may prompt consideration of a central disorder of hypersomnolence (CDH). Narcolepsy is the archetypal and most studied form of CDH and a detailed review of the presentation, evaluation, treatment of narcolepsy is included separately in this edition of Seminars in Pediatric Neurology. In addition to narcolepsy, 2 other forms of primary CDH exist, idiopathic hypersomnia (IH) and Kleine-Levin syndrome (KLS). Onset of IH and KLS occurs most frequently during the pediatric age range and presentation may include signs of encephalopathy in addition to hypersomnolence. As such, they are of particular relevance to pediatric neurology and associated fields. Unfortunately, when compared to narcolepsy little is known about IH and KLS, at both the physiologic and clinical level. This review will focus on the presentation, evaluation, and management of idiopathic hypersomnia and Kleine-Levin syndrome in the pediatric population.

Idiopathic hypersomnia and Kleine-Levin syndrome.

Idiopathic hypersomnia (IH) and Kleine-Levin syndrome (KLS) are rare disorders of central hypersomnolence of unknown cause, affecting young people. However, increased sleep time and excessive daytime sleepiness (EDS) occur daily for years in IH, whereas they occur as relapsing/remitting episodes associated with cognitive and behavioural disturbances in KLS. Idiopathic hypersomnia is characterized by EDS, prolonged, unrefreshing sleep at night and during naps, and frequent morning sleep inertia, but rare sleep attacks, no cataplexy and sleep onset in REM periods as in narcolepsy. The diagnosis requires: (i) ruling out common causes of hypersomnolence, including mostly sleep apnea, insufficient sleep syndrome, psychiatric hypersomnia and narcolepsy; and (ii) obtaining objective EDS measures (mean latency at the multiple sleep latency test≤8min) or increased sleep time (sleep time>11h during a 18-24h bed rest). Treatment is similar to narcolepsy (except for preventive naps), including adapted work schedules, and off label use (after agreement from reference/competence centres) of modafinil, sodium oxybate, pitolisant, methylphenidate and solriamfetol. The diagnosis of KLS requires: (i) a reliable history of distinct episodes of one to several weeks; (ii) episodes contain severe hypersomnia (sleep>15h/d) associated with cognitive impairment (mental confusion and slowness, amnesia), derealisation, major apathy or disinhibited behaviour (hypersexuality, megaphagia, rudeness); and (iii) return to baseline sleep, cognition, behaviour and mood after episodes. EEG may contain slow rhythms during episodes, and rules out epilepsy. Functional brain imaging indicates hypoactivity of posterior associative cortex and hippocampus during symptomatic and asymptomatic periods. KLS attenuates with time when starting during teenage, including less frequent and less severe episodes. Adequate sleep habits, avoidance of alcohol and infections, as well as lithium and sometimes valproate (off label, after agreement from reference centres) help reducing the frequency and severity of episodes, and IV methylprednisolone helps reducing long (>30d) episode duration.

Sleep Disorder Kleine-Levin Syndrome (KLS) Joins the List of Polygenic Brain Disorders Associated with Obstetric Complications.

Kleine-Levin Syndrome is a rare neurological disorder with onset typically during adolescence that is characterized by recurrent episodes of hypersomnia, behavioral changes, and cognitive abnormalities, in the absence of structural changes in neuroimaging. As for many functional brain disorders, the exact disease mechanism in Kleine-Levin Syndrome is presently unknown, preventing the development of specific treatment approaches or protective measures. Here we review the pathophysiology and genetics of this functional brain disorder and then present a specific working hypothesis. A neurodevelopmental mechanism has been suspected based on associations with obstetric complications. Recent studies have focused on genetic factors whereby the first genome-wide association study (GWAS) in Kleine-Levin Syndrome has defined a linkage at the TRANK1 locus. A Gene x Environment interaction model involving obstetric complications was proposed based on concepts developed for other functional brain disorders. To stimulate future research, we here performed annotations of the genes under consideration for Kleine-Levin Syndrome in relation to factors expected to be associated with obstetric complications. Annotations used data-mining of gene/protein lists related to for hypoxia, ischemia, and vascular factors and targeted literature searches. Tentative links for TRANK1, four additional genes in the TRANK1 locus, and LMOD3-LMO2 are described. Protein interaction data for TRANK1 indicate links to CBX2, CBX4, and KDM3A, that in turn can be tied to hypoxia. Taken together, the neurological sleep disorder, Kleine-Levin Syndrome, shows genetic and mechanistic overlap with well analyzed brain disorders such as schizophrenia, autism spectrum disorder and ADHD in which polygenic predisposition interacts with external events during brain development, including obstetric complications.

Can Quantitative Electroencephalography and Functional Near-Infrared Spectroscopy be a Good Guide in Kleine-Levin Syndrome?

There is scarce literature on functional neuroimaging data in Kleine-Levin syndrome. The current case report presents the electrical and metabolic status of cortical activity utilizing functional near-infrared spectroscopy (fNIRS) and quantitative electroencephalography (qEEG) before and after treatment of symptomatic phase of illness with modafinil.

Proteomic biomarkers of Kleine-Levin syndrome.

STUDY OBJECTIVES: Kleine-Levin syndrome (KLS) is characterized by relapsing-remitting episodes of hypersomnia, cognitive impairment, and behavioral disturbances. We quantified cerebrospinal fluid (CSF) and serum proteins in KLS cases and controls. METHODS: SomaScan was used to profile 1133 CSF proteins in 30 KLS cases and 134 controls, while 1109 serum proteins were profiled in serum from 26 cases and 65 controls. CSF and serum proteins were both measured in seven cases. Univariate and multivariate analyses were used to find differentially expressed proteins (DEPs). Pathway and tissue enrichment analyses (TEAs) were performed on DEPs. RESULTS: Univariate analyses found 28 and 141 proteins differentially expressed in CSF and serum, respectively (false discovery rate <0.1%). Upregulated CSF proteins included IL-34, IL-27, TGF-b, IGF-1, and osteonectin, while DKK4 and vWF were downregulated. Pathway analyses revealed microglial alterations and disrupted blood-brain barrier permeability. Serum profiles show upregulation of Src-family kinases (SFKs), proteins implicated in cellular growth, motility, and activation. TEA analysis of up- and downregulated proteins revealed changes in brain proteins (p < 6 × 10-5), notably from the pons, medulla, and midbrain. A multivariate machine-learning classifier performed robustly, achieving a receiver operating curve area under the curve of 0.90 (95% confidence interval [CI] = 0.78-1.0, p = 0.0006) in CSF and 1.0 (95% CI = 1.0-1.0, p = 0.0002) in serum in validation cohorts, with some commonality across tissues, as the model trained on serum sample also discriminated CSF samples of controls versus KLS cases. CONCLUSIONS: Our study identifies proteomic KLS biomarkers with diagnostic potential and provides insight into biological mechanisms that will guide future research in KLS.

Kleine-Levin syndrome: report of a case with marked dysautonomic features.

Kleine-Levin syndrome is a rare neurologic disorder of unknown etiopathogenesis, characterized by abrupt onset and remission of attacks of hypersomnia and cognitive dysfunctions. Psychiatric symptoms are frequently present, ranging from disinhibited sexual behavior and eating disorders to hallucinations, anxiety, mood alterations, and derealization. A vast range of attack-related dysautonomic signs and symptoms are reported but remain poorly described. We describe a patient with Kleine-Levin syndrome with sleep attacks dominated by marked dysautonomic features. We briefly review similar clinical cases and suggest that the hypothalamus may play a central role in the genesis of autonomic dysfunction in Kleine-Levin syndrome. CITATION: Fiamingo G, Esposto R, Dal Fabbro B, Terzaghi M. Kleine-Levin syndrome: report of a case with marked dysautonomic features. J Clin Sleep Med. 2022;18(9):2313-2316.

General Anesthetic Management of a Patient With Kleine-Levin Syndrome.

Kleine-Levin syndrome (KLS) is a rare sleep disorder characterized by periodic hypersomnia and behavioral or cognitive disturbances. Although prolonged emergence from general anesthesia and postoperative hypersomnia may occur in a patient with KLS, there is little information about the safe anesthetic management of these patients. We describe the case of a 22-year-old female previously diagnosed with KLS who was scheduled to have her third molars extracted under general anesthesia. Because the patient had symptoms of periodic hypersomnia and hyperphagia, the surgery was scheduled during a KLS crisis interval. General anesthesia was induced with propofol, remifentanil, and rocuronium, and maintained with desflurane and remifentanil. To prevent overuse of anesthetic agents, an electroencephalogram (EEG)-based depth of anesthesia monitor (SedLine; Masimo Corporation) was used intraoperatively. A neuromuscular monitor was also used to carefully titrate use of a neuromuscular blocking agent. After surgery, sugammadex was administered, and the patient quickly emerged within 10 minutes, as also confirmed by the EEG monitor. She had no KLS recurrence postoperatively. When anesthetizing patients with KLS, an EEG-based depth of anesthesia monitor and neuromuscular monitor may be warranted to ensure complete emergence from general anesthesia. In addition, elective surgery should be planned during crises intervals.

LMOD3 gene variant in familial periodic hypersomnolence.

INTRODUCTION: Kleine-Levin syndrome (KLS) is a rare and debilitating disorder presenting with periodic hypersomnolence, cognitive, psychiatric and behavioral disturbances. In the absence of biomarkers it can be difficult to diagnose. Rare LMOD3 variants in a family and in seven sporadic cases with KLS have been described. Here we report a patient and her family with an unclassified, familial, periodic central disorder of hypersomnolence (CDH) in whom the presence of a LMOD3 gene variant was assessed. CASE DESCRIPTION: The female patient presented since early adulthood with recurrent episodes of hypersomnolence. Over more than 20 years of follow-up the diagnoses of idiopathic hypersomnia, KLS and hypersomnia associated with a psychiatric condition were made. The family history is positive for periodic hypersomnolence and psychiatric conditions. The patient, her symptomatic mother and her asymptomatic sister carried a Proline for Histidine substitution at codon 552 of the LMOD3-gene. This variant was previously reported in two sporadic KLS patients and its frequency in the general population is below 0.02%. DISCUSSION: We report the association of periodic hypersomnia with a polymorphism of the LMOD3-gene in a patient with atypical KLS and a positive family history. Further research is needed to assess the pathological and predictive value of LMOD3 variants in KLS.

Increase in the Number and Duration of Sleep Episodes During Class After Reopening of Schools Following Closure due to COVID-19.

Sleep is important for the well-being of school-aged children. Almost all schools in Hyogo prefecture in Japan were closed from April 7 to May 31, 2020, owing to the coronavirus disease 2019 pandemic. The pandemic restrictions resulted in the disruption of the sleep routines of children. The number of children who experienced sleepiness in class after school closure increased. The number of children who visited our hospital 1 year before and after the closure was 208 (11.73 ± 3.24 years of age) and 155 (11.45 ± 3.30 years), respectively. The number of chief complaints of sleep-related symptoms at the first visits showed no significant difference between the two time periods. The percentage of patients who slept during class increased (but not significantly) after the school closure. However, the mean number and duration of sleep episodes during class significantly increased from 0.31 ± 0.76 to 1.04 ± 1.14 episodes/day and from 15.8 ± 38.6 to 45.7 ± 46.9 min/day (each P < 0.001) before and after school closure, respectively. The total number of patients in our hospital with the primary central disorders of hypersomnolence, i.e., narcolepsy, idiopathic hypersomnia, and Kleine-Levin syndrome, and the number of patients with insufficient sleep syndrome after the school closure significantly increased compared with those before closure (P = 0.034 and 0.048, respectively). School closure was associated with an increased incidence of sleeping during class; therefore, maintaining a stable daily routine for children with sleep disorders could have an alleviating effect.

Self-representation in Kleine-Levin syndrome: a single case fMRI study.

Kleine-Levin syndrome (KLS) is characterized by recurrent episodes of hypersomnia, compulsive hyperphagia, disinhibition, hypersexuality and self modifications. To investigate the Self, we used afunctional magnetic resonance imaging paradigm evaluating Self-reference processing (SRP) and Self-reference effect (SRE) in a17-year-old male adolescent at the end of an episode. We observed enhanced activations in right hemisphere and posterior areas- associated with physical Self representations- during the SRP condition, while during the SRE condition, enhanced activations in bilateral but prevailing left frontal areas- associated with the conceptual Self. These results suggest amodified Self during aKLS episode being more physically grounded.

Kleine-Levin syndrome related to pregnancy: a case report.

Kleine-Levin syndrome (KLS) is a rare disorder of recurrent hypersomnolence. The pathophysiology continues to be poorly understood. Autoimmunity, genetic polymorphisms, dysfunction of the hypothalamic axis, and abnormalities in functional imaging have been proposed. Several triggers have been described, including infection, toxins, head trauma, sleep deprivation, lactation, and menses. We present the first case report in the medical literature of KLS triggered by pregnancy and the first case of KLS from Armenia. Our patient has a pattern of mostly pregnancy-related episodes of several day sleepiness occurring monthly. This case adds to the published literature as we present a new association and explore the pathophysiology of KLS. CITATION: Khachatryan SG, Lastra AC, Vardanyan LV, Khachatryan LG, Attarian HP. Kleine-Levin syndrome related to pregnancy: a case report. J Clin Sleep Med. 2021;17(11):2325-2327.