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Anti-NMDAR encephalitis has a psychotic presentation that is difficult to distinguish from primary psychosis. An atypical psychosis that is similar to schizophrenia, mood disorder, and epilepsy is unique, and the original diagnostic criteria exist only in Japan. The clinical symptoms and courses of anti-NMDAR encephalitis and atypical psychosis are very similar. We investigated whether the diagnostic criteria of atypical psychosis are useful to increase the detection rate of anti-NMDAR encephalitis with psychiatric symptoms. The presence of anti-NR1/NR2B IgG antibodies in the cerebrospinal fluid of 218 newly admitted inpatients initially diagnosed with schizophrenia (n = 151), mood disorder (n = 47), or epilepsy with psychiatric symptoms (n = 20) was assessed by cell-based assay. Of 218 patients, 123 (36.3 years ± SD 17.2, 69.9 % females) fulfilled the diagnostic criteria of category B for atypical psychosis. All 12 patients (9.8 %, 12/123) with anti-NR1/NR2B IgG antibodies fulfilled category B of atypical psychosis statistically better than the patients without anti-NR1/NR2B IgG antibodies (P = 0.0009). Of the 12 patients with anti-NMDAR antibodies, two did not fulfill either criteria of catatonia (DSM-5) or Graus' diagnostic criteria of anti-NMDAR encephalitis during the time course, and 11 patients showed good prognosis with early immunotherapies. In ROC analysis, abnormal electroencephalogram findings showed the highest sensitivity (0.833) for detection of anti-NR1/NR2B IgG antibodies, and 31.3 % of patients with category B atypical psychosis and abnormal electroencephalogram findings had anti-NMDAR antibodies. Lumbar puncture and detection of anti-NMDAR antibodies should be considered for patients who fulfill atypical psychosis diagnosis criteria with an abnormal electroencephalogram.

Research on mental health in working populations has predominantly focussed on negative outcomes, while studies on the positive aspects of life remain very limited, especially in Japan. Although morningness has recently been considered a factor for being happy, the role of sleep characteristics as it relates to the association between morningness and happiness has not been substantiated. The aim of this study is to investigate the associations between diurnal preference and level of subjective happiness in healthy, full-time, daytime workers in Japan. We also tested the moderation effect of sleep parameters on the relationship between diurnal preference and subjective happiness. This is an exploratory analysis from the cross-sectional data of the SLeep Epidemiology Project at the University of Tsukuba (SLEPT Study). Subjective happiness was evaluated using a single-item question. Diurnal preference was assessed using the Morningness-Eveningness Questionnaire (MEQ), in which higher scores indicate greater tendency to have morning preference. The participants underwent assessment of sleep parameters for 7 consecutive days using a waist-worn actigraphy device and kept a sleep diary. Sleep parameters investigated were subjective sleep quality, sleep disturbance, daytime sleepiness, weekend oversleep, total sleep time, sleep onset time, wake time, and sleep efficiency. A total of 205 males (average 42.6 ± 10.4 years) and 272 females (41.1 ± 9.8 years) were eligible for analysis. Hierarchical liner regression analysis was used to show the relationships of subjective happiness with MEQ score, and the sleep parameters. Further, moderation analysis was conducted by adding the interaction between MEQ score and the sleep parameters. After adjusting for age, psychological distress, self-rated health, and occupational stress, we found that subjective happiness was significantly associated with higher MEQ score and sleep efficiency but only in female. The moderating role of sleep parameters was not found. We discussed the implications of the obtained results and a possible strategy to maintain and improve subjective happiness of female workers who have evening preference.

Idiopathic hypersomnia (IH) is a rare sleep disorder characterized by excessive daytime sleepiness, great difficulty upon awakening, and prolonged sleep time. In contrast to narcolepsy type 1, which is a well-recognized hypersomnia, the etiology of IH remains poorly understood. No susceptibility loci for IH have been identified, although familial aggregations have been observed among patients with IH. Narcolepsy type 1 is strongly associated with human leukocyte antigen (HLA)-DQB1*06:02; however, no significant associations between IH and HLA alleles have been reported. To identify genetic variants that affect susceptibility to IH, we performed a genome-wide association study (GWAS) and two replication studies involving a total of 414 Japanese patients with IH and 6587 healthy Japanese individuals. A meta-analysis of the three studies found no single-nucleotide polymorphisms (SNPs) that reached the genome-wide significance level. However, we identified several candidate SNPs for IH. For instance, a common genetic variant (rs2250870) within an intron of PDE9A was suggestively associated with IH. rs2250870 was significantly associated with expression levels of PDE9A in not only whole blood but also brain tissues. The leading SNP in the PDE9A region was the same in associations with both IH and PDE9A expression. PDE9A is a potential target in the treatment of several brain diseases, such as depression, schizophrenia, and Alzheimer’s disease. It will be necessary to examine whether PDE9A inhibitors that have demonstrated effects on neurophysiologic and cognitive function can contribute to the development of new treatments for IH, as higher expression levels of PDE9A were observed with regard to the risk allele of rs2250870. The present study constitutes the first GWAS of genetic variants associated with IH. A larger replication study will be required to confirm these associations.

Purpose Multiple sleep latency test (MSLT) is performed as objective assessment of sleepiness, on the following day after polysomnography (PSG). In most clinics, patients are required to stay for 2 days. However, if patients have chronic sleep debt before the examination, even if they get adequate nocturnal sleep during the initial PSG, their sleep debt would not be fully resolved, affecting MSLT results. This may lead to improper administration of psycho‐stimulant medication. To clarify the sleep debt for the patients who showed short sleep latencies, we compared the mean sleep latencies of MSLTs. Methods Twelve hypersomnolent males, who underwent MSLTs (1st MSLT with 1 night and 2nd MSLT with more than 3 nights), were enrolled. We selected these cases based on the longer total sleep time on PSG night compared to the mean total sleep time on pre‐examination sleep logs and shortened sleep latencies on PSG. To evaluate the effect of the sleep debt for the patients who showed short sleep latencies, we extended their hospitalization or re‐hospitalized them. Results The mean sleep latency of 1st MSLT was 5.8 minutes and that of 2nd was 13.9 minutes (P, (a) Mean sleep latency following the nights in the hospital: the plots show mean sleep latencies of multiple sleep latency test (MSLT) in each patient following nights in the hospital. The number of patients was 12, and MSLT was conducted twice per patient. (b) Comparison of mean sleep latency obtained from MSLT between 1st MSLTs and 2nd MSLTs: The longer the hospitalized period, the patients showed longer mean sleep latencies.

The phenotypes of patients with disease-associated variants in DNMT1 have been classified into two syndromes: hereditary sensory and autonomic neuropathy type 1E (HSAN1E, MIM614116, https://www.omim.org/ ) and autosomal dominant cerebellar ataxia, deafness, and narcolepsy (ADCA-DN, MIM604121). The amino acid codon 511 is a hotspot, and p.Y511C is the most frequently observed disease-associated variant among those in HSAN1E patients, whereas there have been only a few reports on patients with p.Y511H. In this study, we report on the cases of a kindred carrying the DNMT1 variant NM_001130823.2:c.1531 T > C (p.Y511H) presenting with the ADCA-DN phenotype. The review of the literature further revealed that later ages at onset and the presence of cerebellar ataxia are the main characteristics of patients carrying the DNMT1 p.Y511H as compared with those carrying DNMT1 p.Y511C. Although HSAN1E and ADCA-DN are proposed to be called DNMT1-complex disorders owing to their overlapping symptoms, this finding suggests a distinct genotype–phenotype correlation regarding the DNMT1 p.Y511H and p.Y511C variants.

Cataplexy is a sudden drop of antigravity-muscle tone triggered most often by positive emotional factors, which is one of the major symptoms of narcolepsy. Cataplexy has been treated pharmacologically, most often with tricyclic antidepressants. Even though tricyclic antidepressants are effective in reducing sleep paralysis and hypnagogic hallucinations, they even enhance daytime sleepiness, dizziness, and orthostatic hypotension. We assessed the anticataplectic effect of milnacipran, an SNRI, on human and canine narcolepsy. We also assessed the effect of milnacipran on REM sleep suppression in nocturnal sleep. Ten human patients with narcolepsy–cataplexy who changed medication from clomipramine to milnacipran due to side effects were enrolled. The change in the frequency of cataplexy and side effects before and after drug replacement was investigated. To assess milnacipran’s depressant effect on REM sleep, we performed nocturnal polysomnography examinations twice on each eight healthy adult subjects who were administered with milnacipran or placebo. In the study on canine narcolepsy, four genetically narcoleptic Doberman pinschers were enrolled. The food-elicited cataplexy test was used to assess the anticataplectic effect of milnacipran. Milnacipran significantly reduced cataplexy from 9.3 to 5.5 episodes per month in human patients without much side effects. The percentage of REM sleep significantly decreased (p = 0.042) in the subjects with milnacipran (17.5 ± 1.7%) compared to subjects with placebo (21.5 ± 2.3%). Milnacipran also significantly reduced cataplexy dose-dependently in the study on canine narcolepsy. Milnacipran reduced cataplexy in human patients and REM sleep in healthy human subjects. Our study contributes further to previously reported role of adrenergic uptake inhibition in cataplexy. This compound had less side effect than those of tricyclic antidepressant, clomipramine.

We examined whether symptoms of dementia are improved by olfactory nerve stimulation in Alzheimer type dementia patients. First, a stick‐type olfactory identification ability test was performed in patients with Alzheimer type dementia, to select patients without olfactory dysfunctions. Then, these patients were randomly assigned into the intervention (n = 19) and the control groups (n = 17). To evaluate the effects of olfactory nerve stimulation, we exposed the intervention group to a disinfecting ethanol with added aroma extracts from ceder and the control group to the ethanol without the added aroma extracts. Each group underwent the intervention for 8 weeks, cognitive and behavioral functions were evaluated before and after treatments using the Neuropsychiatric Inventory (NPI), the Japanese version of Zarit Caregiver Burden interview (J‐ZBI), and the Alzheimer's Disease Assessment Scale‐cognitive subscale (ADAS‐cog). A significant improvement was observed in the NPI score and J‐ZBI in the intervention group compared to the control group at 4 and 8 weeks. On the other hand, there was no significant difference in the score of ADAS‐cog. Exposure to cedar fragrance improved behavioral and psychological symptoms of dementia (BPSD) in Alzheimer type dementia and may reduce the burden of nursing care. In addition to its effectiveness, the procedure is simple and minimally invasive and would be a valuable non‐pharmaceutical treatment.

Background Recently, many studies have investigated the association between orexin A and Alzheimer's disease (AD). However, it remains to be determined whether the observed changes in orexin A levels are associated with pathological changes underlying AD, or cognitive function. In particular, a direct association between cerebrospinal fluid (CSF) orexin A levels and cognitive function has not been reported to date. Objective The aim of this study was to identify whether there is a direct association between the orexinergic system and cognitive function in AD. Methods For this study, we included 22 patients with AD and 25 control subjects who underwent general physical, neurological, and psychiatric examinations, neuroimaging, and CSF collection by lumbar puncture were enrolled. Correlations between CSF orexin A levels and CSF AD biomarker levels (i.e., levels of phosphorylated tau [p-tau], Aβ42, and Aβ42/Aβ40) were assessed to confirm the results of previous studies. Moreover, the correlation between CSF orexin A levels and Mini-Mental State Examination (MMSE) and Japanese version of the Montreal Cognitive Assessment (MoCA-J) scores were analyzed. Results There was a significant positive correlation between CSF orexin-A levels and cognitive function (MMSE scores: r = 0.591, p = 0.04, MoCA score: r = 0.571, p = 0.006) in AD patients. Conclusion This is the first study to our knowledge demonstrating an association between cognitive function and CSF orexin A levels in AD. Our results suggest the possibility that orexinergic system overexpression is not always a negative factor for cognitive function In AD.

Despite extensive evidence on the organ protective effects of sevoflurane, its effect on disturbed sleep remains unclear. We hypothesised that sevoflurane preconditioning positively impacts disturbed sleep caused by systemic inflammation. A prospective, randomised laboratory investigation was conducted in C57BL/6J mice. A mouse model of lipopolysaccharide (LPS)-induced systemic inflammation was employed to investigate the effects of sevoflurane on sleep recovery. Symptom recovery was evaluated through electroencephalography/electromyography (EEG/EMG) and histological studies. The mice were exposed to 2% sevoflurane before and after peritoneal injection of LPS. The EEG and EMG were recorded for 24 h after the procedure. Brain tissue was harvested after the sevoflurane/LPS procedure and was immunostained using individual antibodies against choline acetyltransferase (ChAT) and Fos. The ChAT-positive and ChAT/Fos double-positive cells were analysed quantitatively in the pedunculopontine tegmental nucleus and laterodorsal tegmental nucleus (PPTg/LDTg). Compared with control mice, mice preconditioned with sevoflurane but not post-conditioned showed a significant increase in rapid eye movement (REM) sleep during EEG recording following the LPS challenge. They also demonstrated a shorter REM latency, indicating an early recovery from LPS-altered sleep. The bouts of REM episodes were retained with sevoflurane preconditioning. More ChAT/Fos double-positive cells were observed in the PPTg/LDTg in the sevoflurane preconditioning plus LPS group than in the LPS-only group. Sevoflurane preconditioning promotes recovery from altered sleep induced by systemic inflammation. Activation of PPTg/LDTg is considered a mechanism underlying sleep reintegration. The recovery phenomenon shows potential for clinical application in cases of sleep disturbances induced by systemic inflammation.

RATIONALE Adequate immunotherapies for anti-NMDAR encephalitis during pregnancy produce a relatively good clinical outcome for pregnant mothers and their infants, but there are no reports about the future growth of their babies. The damage of anti-NMDAR antibodies to early neuronal development is still unknown. OBJECTIVES Serum or cerebrospinal fluid from one patient with anti-NMDAR encephalitis (the index patient) and one patient with schizophrenia (the control patient) was administered to primary cultures of dissociated rat cortical neurons, and dendritic outgrowth, centrosome elimination, and branching of dendrites were investigated. For rescue experiments, serum of the index patient was replaced with normal culture media after 3 days' administration of the index patient. RESULTS Serum and cerebrospinal fluid of the index patient statistically significantly impaired dendritic outgrowth of cultured rat cortical primary neurons. Serum of the index patient also statistically significantly delayed centrosome elimination. Impaired dendritic outgrowth and delayed centrosome elimination were not perfectly rescued by changing to normal culture media. Serum of the index patient also statistically significantly reduced the branching of dendrites. CONCLUSIONS This is the first demonstration of the damage by anti-NMDAR antibodies on early dendritic development in vitro. As a strategy to protect embryonic neurons, our findings may support the efficacy of early immunotherapy for anti-NMDAR encephalitis in pregnancy.

Introduction Anesthesia and sleep partially share neural circuits, yet little is known regarding the effect of anesthetics on sleep. Anesthetic agents exhibit a variety of biological effects concomitant with anesthesia. Sevoflurane, one of the wildly used volatile anesthetics, is known to increase the survival of sepsis model mice. Systemic inflammation like sepsis increases the inflammatory mediators in the brain affecting sleep dynamics with increase in NREM and decrease in REM. We hypothesized that sevoflurane preconditioning positively impacts disturbed sleep caused by systemic inflammation. Methods We conducted a prospective, randomized laboratory investigation in C57BL/6J mice. A mouse model of lipopolysaccharide (LPS)-induced systemic inflammation was employed to investigate the effects of sevoflurane on sleep recovery. We evaluated symptoms recovery through electroencephalography/electromyography (EEG/EMG) and histological studies. The mice were exposed to 2% sevoflurane before and after peritoneal injection of LPS. The EEG and EMG were recorded for 24 h after the procedure. Brain tissue was harvested after the sevoflurane/LPS procedure and was immunostained using individual antibodies against choline acetyltransferase (ChAT) and Fos.[YI1] We quantitatively analyzed the ChAT-positive and ChAT/Fos double-positive cells in the pedunculopontine tegmental nucleus and laterodorsal tegmental nucleus (PPTg/LDTg). Results Compared to control mice, mice preconditioned with sevoflurane but not post-conditioned showed a significant recuperation in rapid eye movement (REM) sleep and waking time during EEG recording following the LPS challenge. They also demonstrated shorter REM latency and restored theta power, indicating an early recovery from LPS-altered sleep. The bouts of REM episodes were retained with sevoflurane preconditioning. The number of ChAT/Fos double-positive cells in the PPTg/LDTg decreased by LPS challenge. However, group with sevoflurane preconditioning followed by LPS challenge showed higher number of activated neurons, restoring physiological degree of activation. Conclusion Compared to control mice, mice preconditioned with sevoflurane but not post-conditioned showed a significant recuperation in rapid eye movement (REM) sleep and waking time during EEG recording following the LPS challenge. They also demonstrated shorter REM latency and restored theta power, indicating an early recovery from LPS-altered sleep. The bouts of REM episodes were retained with sevoflurane preconditioning. The number of ChAT/Fos double-positive cells in the PPTg/LDTg decreased by LPS challenge. However, group with sevoflurane preconditioning followed by LPS challenge showed higher number of activated neurons, restoring physiological degree of activation. Support (If Any)

Anti-NMDAR encephalitis is increasingly recognized as one etiology of psychiatric symptoms, but there is not enough evidence on patients with mood disorder. We assayed anti-NR1/NR2B IgG antibodies in serum and/or cerebrospinal fluid of 62 patients initially diagnosed with mood disorder by a cell-based assay. We also investigated the specific patient characteristics and psychotic symptoms. At first admission, the patients showed only psychiatric symptoms without typical neurological signs or abnormal examination findings. Four of the 62 patients had anti-NR1/NR2B IgG antibodies. The anti-NR1/NR2B IgG antibody-positive patients showed more super- or abnormal sensitivity (P = 0.00088), catatonia (P = 0.049), and more conceptual disorganization (P 0.0001), hostility (P = 0.0010), suspiciousness (P 0.0001), and less emotional withdrawal (P 0.0001) and motor retardation (P 0.0001) on the Brief Psychiatric Rating Scale than the antibody-negative patients. During the clinical course, anti-NR1/NR2B IgG antibody-positive patients showed more catatonia (P = 0.0042) and met Graus's criteria for diagnosis of anti-NMDAR encephalitis, but negative patients did not. Immunotherapy was effective for anti-NR1/NR2B IgG antibody-positive patients, and there was the weak relationship (R² = 0.318) between the anti-NR1/NR2B IgG antibody titer in the cerebrospinal fluid and the Brief Psychiatric Rating Scale score.

Objective The objective of this study was to investigate the relationship between the serum concentration of clozapine (C-CLZ), Ndesmethylclozapine (N-CLZ) and the daily dose of CLZ (D-CLZ), and the relationships among CLZ and electroencephalogram (EEG) abnormalities. Methods Twenty-eight patients were recruited to this study, but 8 patients were excluded because clozapine was discontinued before the post-treatment measurement of EEG or C-CLZ. Ultimately, 20 patients (6 men, 14 women) with an average age of 36 years were enrolled. The subjects were divided into EEG normal and abnormal groups. C-CLZ and N-CLZ were measured at 4, 12, 26, and 52 weeks after initiating CLZ administration. Results All patients had normal baseline EEG signals, and 8 patients showed EEG abnormalities later. There were significant correlations between C-CLZ and D-CLZ, and between N-CLZ and D-CLZ. The C-CLZ/D-CLZ, N-CLZ/D-CLZ, and C-CLZ/N-CLZ ratio were not significantly different between the EEG normal and EEG abnormal groups. The EEG abnormal group had significant higher proportion of patients with high intra-individual variability in their C-CLZ/D-CLZ ratio. Conclusion There is no relationship between C-CLZ and EEG abnormalities. However, patients with high intra-individual variability in their C-CLZ/D-CLZ ratio had greater possibility of exhibiting EEG abnormalities.

Kleine-Levin syndrome (KLS) is a rare disorder characterized by severe episodic hypersomnia, with cognitive impairment accompanied by apathy or disinhibition. Pathophysiology is unknown, although imaging studies indicate decreased activity in hypothalamic/thalamic areas during episodes. Familial occurrence is increased, and risk is associated with reports of a difficult birth. We conducted a worldwide case−control genome-wide association study in 673 KLS cases collected over 14 y, and ethnically matched 15,341 control individuals. We found a strong genome-wide significant association (rs71947865, Odds Ratio [OR] = 1.48, P = 8.6 × 10(−9)) within the 3′region of TRANK1 gene locus, previously associated with bipolar disorder and schizophrenia. Strikingly, KLS cases with rs71947865 variant had significantly increased reports of a difficult birth. As perinatal outcomes have dramatically improved over the last 40 y, we further stratified our sample by birth years and found that recent cases had a significantly reduced rs71947865 association. While the rs71947865 association did not replicate in the entire follow-up sample of 171 KLS cases, rs71947865 was significantly associated with KLS in the subset follow-up sample of 59 KLS cases who reported birth difficulties (OR = 1.54, P = 0.01). Genetic liability of KLS as explained by polygenic risk scores was increased (pseudo R(2) = 0.15; P < 2.0 × 10(−22) at P = 0.5 threshold) in the follow-up sample. Pathway analysis of genetic associations identified enrichment of circadian regulation pathway genes in KLS cases. Our results suggest links between KLS, circadian regulation, and bipolar disorder, and indicate that the TRANK1 polymorphisms in conjunction with reported birth difficulties may predispose to KLS.

Kleine-Levin syndrome (KLS) is a rare disorder characterized by severe episodic hypersomnia, with cognitive impairment accompanied by apathy or disinhibition. Pathophysiology is unknown, although imaging studies indicate decreased activity in hypothalamic/thalamic areas during episodes. Familial occurrence is increased, and risk is associated with reports of a difficult birth. We conducted a worldwide case.control genome-wide association study in 673 KLS cases collected over 14 y, and ethnically matched 15,341 control individuals. We found a strong genome-wide significant association (rs71947865, Odds Ratio [OR] = 1.48, P = 8.6 × 10-9) within the 3'region of TRANK1 gene locus, previously associated with bipolar disorder and schizophrenia. Strikingly, KLS cases with rs71947865 variant had significantly increased reports of a difficult birth. As perinatal outcomes have dramatically improved over the last 40 y, we further stratified our sample by birth years and found that recent cases had a significantly reduced rs71947865 association. While the rs71947865 association did not replicate in the entire follow-up sample of 171 KLS cases, rs71947865 was significantly associated with KLS in the subset follow-up sample of 59 KLS cases who reported birth difficulties (OR = 1.54, P = 0.01). Genetic liability of KLS as explained by polygenic risk scores was increased (pseudo R2= 0.15; P < 2.0 ∼ 10-22at P = 0.5 threshold) in the follow-up sample. Pathway analysis of genetic associations identified enrichment of circadian regulation pathway genes in KLS cases. Our results suggest links between KLS, circadian regulation, and bipolar disorder, and indicate that the TRANK1 polymorphisms in conjunction with reported birth difficulties may predispose to KLS.

Objectives Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is an increasingly recognized etiology of psychiatric symptoms. Because patients with anti-NMDAR encephalitis frequently show aggression, mania, hallucination, depression, or delusion, they are initially diagnosed with schizophrenia or mood disorders. There is only 1 case report of an initially diagnosed dissociative disorder. Methods We obtained consent for the presentation and have not identified individuals for ethical reasons. Results We first report an adolescent female patient with anti-NMDAR encephalitis who was initially suspected of having dissociative disorder but was responsive to immunotherapies including rituximab. In this case, her symptoms and electroencephalogram findings were proportional to the antibody titer in the cerebrospinal fluid. Conclusions It is important to consider the possibility of autoimmune encephalitis and immunotherapy including rituximab in cases of not only acute psychosis but also dissociation.

Kleine-Levin Syndrome (KLS) is a rare disorder characterized by severe episodic hypersomnia, with cognitive impairment accompanied by apathy or disinhibition. Pathophysiology is unknown, although imaging studies indicate decreased activity in hypothalamic/thalamic areas during episodes. Familial occurrence is increased, and risk is associated with reports of a difficult birth. We conducted a worldwide case-control genome wide association study in 673 KLS cases collected over 14 years, and ethnically matched 15,341 control individuals. We found a strong genome-wide significant association (OR=1.48,rs71947865,p=8.6×10−9) with 20 single nucleotide polymorphisms encompassing a 35kb region located in the 3’ region ofTRANK1gene, previously associated with bipolar disorder and schizophrenia. Strikingly, KLS cases withTRANK1rs71947865 variant had significantly increased reports of a difficult birth. As perinatal outcomes have dramatically improved over the last 40 years, we further stratified our sample by birth years and found that recent cases had a significantly reducedTRANK1rs71947865 association. While theTRANK1rs71947865 association did not replicate in the entire follow-up sample of 171 KLS cases, the TRANK1 rs71947865 was significantly associated with KLS in the subset follow-up sample of 59 KLS cases who reported birth difficulties (OR=1.54;p=0.01). Genetic liability of KLS as explained by polygenic risk scores was increased (pseudo r2=0.15;p−22at p=0.5 threshold) in the follow-up sample. Pathway analysis of genetic associations identified enrichment of circadian regulation pathway genes in KLS cases. Our results suggest links between KLS, behavioral rhythmicity, and bipolar disorder, and indicates that theTRANK1polymorphisms in conjunction with reported birth difficulties may predispose to KLS.Significance StatementGenetic markers inTRANK1gene and its vicinity have been weakly associated with bipolar disorder and schizophrenia (10% increased risk). We found that the same polymorphisms are associated with Kleine-Levin Syndrome (50% increased risk), a rare sleep disorder characterized by recurrent episodes of severe hypersomnia and cognitive abnormalities. Response to lithium treatment are suggestive of a pathophysiological overlap between KLS and bipolar disorder. The study also shows that variants in theTRANK1gene region may predispose to KLS when patients have had a difficult birth, suggesting thatTRANK1gene region modulate newborns’ response to brain injury, with consequences for mental and neurological health in adulthood. Another possibility may be that the polymorphism impact birth and KLS.

Orexins/hypocretins are hypothalamic neuropeptides that promote and stabilize wakefulness by binding to the orexin receptor type-1 (OX1R) and type-2 (OX2R). Disruption of orexinergic signaling results in the sleep disorder narcolepsy in mice, rats, dogs, and humans. The orexin receptor antagonist suvorexant promotes sleep by blocking both OX1R and OX2R. Whereas suvorexant has been clinically approved for the treatment of insomnia because it is well tolerated in experimental animals as well as in human patients, a logical question remains as to why orexin receptor antagonists do not induce overt narcolepsy-like symptoms. Here we show that acute and chronic suvorexant promotes both rapid eye movement (REM) and non-rapid eye movement (NREM) sleep without inducing cataplexy in mice. Interestingly, chronic suvorexant increases OX2R mRNA and decreases orexin mRNA and peptide levels, which remain low long after termination of suvorexant administration. When mice are chronically treated with suvorexant and then re-challenged with the antagonist after a 1-week washout, however, cataplexy and sleep-onset REM (SOREM) are observed, which are exacerbated by chocolate administration. Heterozygous orexin knockout mice, with lower brain orexin levels, show cataplexy and SOREM after acute suvorexant administration. Furthermore, we find that acute suvorexant can induce cataplexy and SOREM in wild-type mice when co-administered with chocolate under stress-free (temporally anesthetized) conditions. Taken together, these results suggest that suvorexant can inhibit orexin synthesis resulting in susceptibility to narcolepsy-like symptoms in mice under certain conditions.

Study objectives Niemann-Pick type C (NPC) is an autosomal recessive and congenital neurological disorder characterized by the accumulation of cholesterol and glycosphingolipids. Symptoms include hepatosplenomegaly, vertical supranuclear saccadic palsy, ataxia, dystonia, and dementia. Some cases frequently display narcolepsy-like symptoms, including cataplexy which was reported in 26% of all NPC patients and was more often recorded among late-infantile onset (50%) and juvenile onset (38%) patients. In this current study, we examined CSF orexin levels in the 10 patients of NPC with and without cataplexy, which supports previous findings. Methods Ten patients with NPC were included in the study (5 males and 5 females). NPC diagnosis was biochemically confirmed in all 10 patients, from which 8 patients with NPC1 gene were identified. We compared CSF orexin levels among NPC, narcoleptic and idiopathic hypersomnia patients. Results Six NPC patients with cataplexy had low or intermediate orexin levels. In 4 cases without cataplexy, their orexin levels were normal. In 5 cases with Miglustat treatment, their symptoms stabilized or improved. For cases without Miglustat treatment, their conditions worsened generally. The CSF orexin levels of NPC patients were significantly higher than those of patients with narcolepsy-cataplexy and lower than those of patients with idiopathic hypersomnia, which was considered as the control group with normal CSF orexin levels. Discussion Our study indicates that orexin level measurements can be an early alert of potential NPC. Low or intermediate orexin levels could further decrease due to reduction in the neuronal function in the orexin system, accelerating the patients’ NPC pathophysiology. However with Miglustat treatment, the orexin levels stabilized or improved, along with other general symptoms. Although the circuitry is unclear, this supports that orexin system is indeed involved in narcolepsy-cataplexy in NPC patients. Conclusion The NPC patients with cataplexy had low or intermediate orexin levels. In the cases without cataplexy, their orexin levels were normal. Our study suggests that orexin measurements can serve as an early alert for potential NPC; furthermore, they could be a marker of therapy monitoring during a treatment.

The phenotypes of patients with disease-associated variants in DNMT1 have been classified into two syndromes: hereditary sensory and autonomic neuropathy type 1E (HSAN1E, MIM614116, https://www.omim.org/ ) and autosomal dominant cerebellar ataxia, deafness, and narcolepsy (ADCA-DN, MIM604121). The amino acid codon 511 is a hotspot, and p.Y511C is the most frequently observed disease-associated variant among those in HSAN1E patients, whereas there have been only a few reports on patients with p.Y511H. In this study, we report on the cases of a kindred carrying the DNMT1 variant NM_001130823.2:c.1531 T C (p.Y511H) presenting with the ADCA-DN phenotype. The review of the literature further revealed that later ages at onset and the presence of cerebellar ataxia are the main characteristics of patients carrying the DNMT1 p.Y511H as compared with those carrying DNMT1 p.Y511C. Although HSAN1E and ADCA-DN are proposed to be called DNMT1-complex disorders owing to their overlapping symptoms, this finding suggests a distinct genotype-phenotype correlation regarding the DNMT1 p.Y511H and p.Y511C variants.

Narcolepsy is characterized by excessive sleepiness, hypnagogic hallucinations, and sleep paralysis, and can occur with or without cataplexy. Here, we report two children with narcolepsy presenting with cataplexy mimicking epileptic seizures as determined by long-term video-electroencephalography (EEG) and electromyography (EMG) monitoring. Case 1 was a 15-year-old girl presenting with recurrent episodes of “convulsions” and loss of consciousness, who was referred to our hospital with a diagnosis of epilepsy showing “convulsions” and “complex partial seizures”. The long-term video-polygraph showed a clonic attack lasting for 15 s, which corresponded to 1–2 Hz with interruption of mentalis EMG discharges lasting for 70–300 ms without any EEG changes. Narcolepsy was suspected due to the attack induced by hearty laughs and the presence of sleep attacks, and confirmed by low orexin levels in cerebrospinal fluid (CSF). Case 2 was an 11-year-old girl presenting with recurrent episodes of myoclonic attacks simultaneously with dropping objects immediately after hearty laughs, in addition to sleep attacks, hypnagogic hallucinations, and sleep paralysis. The long-term video-polygraph showed a subtle attack, characterized by dropping chopsticks from her hand, which corresponded to an interruption of ongoing deltoid EMG discharges lasting 140 ms without any EEG changes. A diagnosis of narcolepsy was confirmed by the low orexin levels in CSF. These cases demonstrate that children with narcolepsy may have attacks of cataplexy that resemble clonic or myoclonic seizures.

Symptomatic narcolepsy is characterized as low orexin (hypocretin) levels (≤ 110 pg/ml) due to neurological diseases. However, we have experienced the cases that show symptoms similar to narcolepsy, complaining of pathological sleepiness even in cases with intermediate orexin levels (110–200 pg/ml). Therefore, we reevaluated the previously reported cases to make the concept of disease to the group in which the orexin concentration is intermediate. Although orexin-deficient symptomatic narcolepsy has been reported worldwide, facilities that are capable of measuring orexin are still limited. Currently, our laboratory handles with almost all the CSF samples from Asian countries for determining orexin levels. We measured over 2500 cases including 182 cases suspected of symptomatic narcolepsy/hypersomnolence. Therefore, we subdivided these cases into three groups according to CSF orexin levels, low orexin group (≤ 110 pg/ml), intermediate orexin group (110–200 pg/ml), and normal orexin group (> 200 pg/ml). We defined “symptomatic hypersomnia” for hypersomnolence cases with intermediate CSF orexin levels. MSLT was recommended but not necessary. Short sleep latency (

Essential hypersomnia (EHS) is a lifelong disorder characterized by excessive daytime sleepiness without cataplexy. EHS is associated with human leukocyte antigen (HLA)-DQB1*06:02, similar to narcolepsy with cataplexy (narcolepsy). Previous studies suggest that DQB1*06:02-positive and -negative EHS are different in terms of their clinical features and follow different pathological pathways. DQB1*06:02-positive EHS and narcolepsy share the same susceptibility genes. In the present study, we report a genome-wide association study with replication for DQB1*06:02-negative EHS (408 patients and 2247 healthy controls, all Japanese). One single-nucleotide polymorphism, rs10988217, which is located 15-kb upstream of carnitine O-acetyltransferase (CRAT), was significantly associated with DQB1*06:02-negative EHS (P = 7.5 × 10−9, odds ratio = 2.63). The risk allele of the disease-associated SNP was correlated with higher expression levels of CRAT in various tissues and cell types, including brain tissue. In addition, the risk allele was associated with levels of succinylcarnitine (P = 1.4 × 10−18) in human blood. The leading SNP in this region was the same in associations with both DQB1*06:02-negative EHS and succinylcarnitine levels. The results suggest that DQB1*06:02-negative EHS may be associated with an underlying dysfunction in energy metabolic pathways.

Narcolepsy-cataplexy is a chronic neurological disorder caused by loss of orexin (hypocretin)-producing neurons, associated with excessive daytime sleepiness, sleep attacks, cataplexy, sleep paralysis, hypnagogic hallucinations, and fragmentation of nighttime sleep. Currently, human narcolepsy is treated by providing symptomatic therapies, which can be associated with an array of side effects. Although peripherally administered orexin does not efficiently penetrate the blood-brain barrier, centrally delivered orexin can effectively alleviate narcoleptic symptoms in animal models. Chronic intrathecal drug infusion through an implantable pump is a clinically available strategy to treat a number of neurological diseases. Here we demonstrate that the narcoleptic symptoms of orexin knockout mice can be reversed by lumbar-level intrathecal orexin delivery. Orexin was delivered via a chronically implanted intrathecal catheter at the upper lumbar level. The computed tomographic scan confirmed that intrathecally administered contrast agent rapidly moved from the spinal cord to the brain. Intrathecally delivered orexin was detected in the brain by radioimmunoassay at levels comparable to endogenous orexin levels. Cataplexy and sleep-onset REM sleep were significantly decreased in orexin knockout mice during and long after slow infusion of orexin (1 nmol/1 µL/h). Sleep/wake states remained unchanged both quantitatively as well as qualitatively. Intrathecal orexin failed to induce any changes in double orexin receptor-1 and -2 knockout mice. This study supports the concept of intrathecal orexin delivery as a potential therapy for narcolepsy-cataplexy to improve the well-being of patients.