Tic disorders in children and adolescents: does the clinical presentation differ in males and females? A report by the EMTICS group.

Tic disorders have a strong male predominance, with a male-to-female ratio of 4:1 in Tourette syndrome (TS) and 2:1 in persistent tic disorders. In other neurodevelopmental conditions, such as autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD), the disparity in sex distribution has been partially related to differences in symptom presentation between males and females. In tic disorders, however, little research has been conducted on this topic, probably due to the limited access to large samples with a significant proportion of females. The aim of this study was to describe sex differences in the clinical presentation of tic disorders in children and adolescents in one of the largest pediatric samples with TS/persistent tic disorders (n = 709, 23.3% females) recruited as part of the European Multicenter Tics in Children Study (EMTICS). Validated measures assessed the severity of tics and comorbid psychiatric symptoms. Using mixed-effect models, we found that sex had a significant influence on the severity of tics, ADHD symptoms, ASD symptoms, and emotional problems. Males had more severe symptoms than females, except for emotional problems. We also observed a statistically significant interaction between sex and age on the severity of tics and compulsions, with females showing higher symptom severity with increasing age than males. These findings indicate that the clinical presentation of TS/persistent tic disorders varies with sex. Males seem to exhibit a more noticeable pattern of clinical symptoms at a younger age that may contribute to their earlier detection in comparison to females.

Investigation of gene-environment interactions in relation to tic severity.

Tourette syndrome (TS) is a neuropsychiatric disorder with involvement of genetic and environmental factors. We investigated genetic loci previously implicated in Tourette syndrome and associated disorders in interaction with pre- and perinatal adversity in relation to tic severity using a case-only (N = 518) design. We assessed 98 single-nucleotide polymorphisms (SNPs) selected from (I) top SNPs from genome-wide association studies (GWASs) of TS; (II) top SNPs from GWASs of obsessive-compulsive disorder (OCD), attention-deficit/hyperactivity disorder (ADHD), and autism spectrum disorder (ASD); (III) SNPs previously implicated in candidate-gene studies of TS; (IV) SNPs previously implicated in OCD or ASD; and (V) tagging SNPs in neurotransmitter-related candidate genes. Linear regression models were used to examine the main effects of the SNPs on tic severity, and the interaction effect of these SNPs with a cumulative pre- and perinatal adversity score. Replication was sought for SNPs that met the threshold of significance (after correcting for multiple testing) in a replication sample (N = 678). One SNP (rs7123010), previously implicated in a TS meta-analysis, was significantly related to higher tic severity. We found a gene-environment interaction for rs6539267, another top TS GWAS SNP. These findings were not independently replicated. Our study highlights the future potential of TS GWAS top hits in gene-environment studies.

Activation in Children and Adolescents Treated With Selective Serotonin Reuptake Inhibitors: A Weighty Reason?

BACKGROUND: Activation is a behavioral adverse event related to the use of psychotropic medication. Its high incidence in pediatrics and in childhood-onset neuropsychiatric disorders suggests it may be linked to neurodevelopment. However, previous studies have scarcely examined the role that factors relevant to developmental pharmacokinetics, such as body weight, may play in the onset of activation in children and adolescents. METHODS: We conducted a retrospective analysis of hospitalized patients to identify the risk factors for activation in children and adolescents treated with selective serotonin reuptake inhibitors. Our focus was on factors related to development, including body weight, to explore the relationship between activation and neurodevelopmental processes. RESULTS: Among the 139 participants (mean age, 14 ± 2.3 years), activation appeared in 29 (20.9%). Age 12 years or younger and comorbid diagnosis of autism spectrum disorder were associated with statistically significant increases in the risk of activation, but no association was found regarding body weight. CONCLUSIONS: Our findings support the hypothesis that activation is closely linked to brain development processes. Longitudinal studies are needed to explore this line of research further.

Investigation of previously implicated genetic variants in chronic tic disorders: a transmission disequilibrium test approach.

Genetic studies in Tourette syndrome (TS) are characterized by scattered and poorly replicated findings. We aimed to replicate findings from candidate gene and genome-wide association studies (GWAS). Our cohort included 465 probands with chronic tic disorder (93% TS) and both parents from 412 families (some probands were siblings). We assessed 75 single nucleotide polymorphisms (SNPs) in 465 parent-child trios; 117 additional SNPs in 211 trios; and 4 additional SNPs in 254 trios. We performed SNP and gene-based transmission disequilibrium tests and compared nominally significant SNP results with those from a large independent case-control cohort. After quality control 71 SNPs were available in 371 trios; 112 SNPs in 179 trios; and 3 SNPs in 192 trios. 17 were candidate SNPs implicated in TS and 2 were implicated in obsessive-compulsive disorder (OCD) or autism spectrum disorder (ASD); 142 were tagging SNPs from eight monoamine neurotransmitter-related genes (including dopamine and serotonin); 10 were top SNPs from TS GWAS; and 13 top SNPs from attention-deficit/hyperactivity disorder, OCD, or ASD GWAS. None of the SNPs or genes reached significance after adjustment for multiple testing. We observed nominal significance for the candidate SNPs rs3744161 (TBCD) and rs4565946 (TPH2) and for five tagging SNPs; none of these showed significance in the independent cohort. Also, SLC1A1 in our gene-based analysis and two TS GWAS SNPs showed nominal significance, rs11603305 (intergenic) and rs621942 (PICALM). We found no convincing support for previously implicated genetic polymorphisms. Targeted re-sequencing should fully appreciate the relevance of candidate genes.

Bruton's tyrosine kinase is required for apoptotic cell uptake via regulating the phosphorylation and localization of calreticulin.

In addition to regulating B cell development and activation, Bruton's tyrosine kinase (Btk) functions downstream of multiple TLRs, including TLR7, to regulate innate immune responses in myeloid cells. Although critical for defense against RNA viruses such as influenza and Sendai virus, recognition of self-RNA by TLR7 also has been shown to be an important contributor to the pathophysiology of systemic lupus erythematosus. To date, the role of Btk in regulating TLR7-mediated responses is poorly understood. In the current study, we have demonstrated a hitherto undiscovered role for Btk in apoptotic cell uptake, identifying the molecular chaperone calreticulin (CRT) as a novel substrate for Btk in regulating this response. CRT together with the transmembrane receptor CD91 function at the cell membrane and regulate uptake of C1q-opsonised apoptotic cells. Our results show that Btk directly phosphorylates CRT and that in the absence of Btk, CRT fails to localize with CD91 at the cell surface and at the phagocytic cup. Critically, a blocking Ab against CRT in wild-type macrophages mimics the inability of Btk-deficient macrophages to phagocytose apoptotic cells efficiently, indicating the critical importance of Btk in regulating CRT-driven apoptotic cell uptake. Our data have revealed a novel regulatory role for Btk in mediating apoptotic cell clearance, with CRT identified as the critical component of the CRT/CD91/C1q system targeted by Btk. Given the importance of clearing apoptotic cell debris to prevent inappropriate exposure of TLRs to endogenous ligands, our results have important implications regarding the role of Btk in myeloid cell function.

Relationship Between Vertebral Fracture Burden, Height Loss, and Pulmonary Function in Postmenopausal Women With Osteoporosis.

The purpose of this analysis was to assess the association of osteoporosis-related vertebral fracture burden and pulmonary function. This study also examined the relationship between vertebral fracture burden and height loss, estimated by arm span - height. This was a single-site and single-visit study. Patients had a history of at least 1 moderate or severe vertebral fracture. Vertebral fracture burden was quantified using the spinal deformity index (SDI). Pulmonary function during inspiration was determined by spirometry. Forty-one women aged 70-91 completed the study. Vertebral fracture burden negatively correlated with forced inspiratory vital capacity and inspiratory time. For each unit increase in SDI, forced inspiratory vital capacity decreased by 1.62%, and inspiratory time decreased by 2.39%. There was no correlation between SDI and measures of inspiratory flow. For each unit increase in SDI, height decreased by about 0.5 cm. Vertebral fractures were associated with decreased lung volume and height loss.

MgtE is a dual-function protein in Pseudomonas aeruginosa.

The opportunistic pathogen Pseudomonas aeruginosa causes a wide range of infections, including chronic biofilm infections in the lungs of individuals with cystic fibrosis. We previously found that the inner-membrane protein MgtE can function both as a magnesium transporter and a virulence modulator, although the exact mechanism governing these activities is unclear. To address this issue, we carried out an experimental characterization of P. aeruginosa MgtE and generated a computer-rendered model. Our in silico analysis demonstrated the structural similarity of P. aeruginosa MgtE to that of the crystal structure of MgtE in Thermus thermophilus. Experimentally, we verified that MgtE is not essential for growth and found that it may not be involved directly in biofilm formation, even under low-magnesium conditions. We demonstrated both magnesium transport and cytotoxicity-regulating functions, and showed that magnesium-binding sites in the connecting helix region of MgtE are vital in coupling these two functions. Furthermore, limiting magnesium environments stimulated mgtE transcriptional responses. Our results suggested that MgtE might play an important role in linking magnesium availability to P. aeruginosa pathogenesis.

Break-induced replication is highly inaccurate.

DNA must be synthesized for purposes of genome duplication and DNA repair. While the former is a highly accurate process, short-patch synthesis associated with repair of DNA damage is often error-prone. Break-induced replication (BIR) is a unique cellular process that mimics normal DNA replication in its processivity, rate, and capacity to duplicate hundreds of kilobases, but is initiated at double-strand breaks (DSBs) rather than at replication origins. Here we employed a series of frameshift reporters to measure mutagenesis associated with BIR in Saccharomyces cerevisiae. We demonstrate that BIR DNA synthesis is intrinsically inaccurate over the entire path of the replication fork, as the rate of frameshift mutagenesis during BIR is up to 2,800-fold higher than during normal replication. Importantly, this high rate of mutagenesis was observed not only close to the DSB where BIR is less stable, but also far from the DSB where the BIR replication fork is fast and stabilized. We established that polymerase proofreading and mismatch repair correct BIR errors. Also, dNTP levels were elevated during BIR, and this contributed to BIR-related mutagenesis. We propose that a high level of DNA polymerase errors that is not fully compensated by error-correction mechanisms is largely responsible for mutagenesis during BIR, with Pol δ generating many of the mutagenic errors. We further postulate that activation of BIR in eukaryotic cells may significantly contribute to accumulation of mutations that fuel cancer and evolution.

Children and adolescents with Tourette's disorder in the USA versus Argentina: behavioral differences may reflect cultural factors.

To explore behavioral differences as possible cultural factors in presentation of psychiatric comorbidity in two clinically referred, consecutively ascertained samples of youth with Tourette's disorder (TD) from New York and Buenos Aires. Subjects were evaluated between 2002 and 2010 at the Tics and Tourette's Clinical and Research Program at the New York University Child Study Center in New York and the Interdisciplinary Center for Tourette's, Obsessive Compulsive Disorder (OCD) and Associated Disorders (CITTTA)/Institute of Cognitive Psychology (INECO) in Buenos Aires. Demographic, diagnostic, tic severity (Yale Global Tic Severity Scale; YGTSS), clinical (Child Behavior Check List-Parent version; CBCL), and global functioning (Global Assessment of Functioning; GAF) data were compared using descriptive statistics. The sample included 111 subjects ages 6-17 years, who met DSM-IV-TR diagnostic criteria for TD. Findings revealed that the BA sample (n = 35) was significantly older at initial evaluation at the tic specialty clinic, and had higher frequency of oppositional defiant disorder (ODD), mood and non-OCD anxiety disorders than the NY sample (n = 76). There were no differences in gender distribution, age at tic onset or TD diagnosis, tic severity, proportion with current diagnoses of OCD/OC behavior or attention deficit hyperactivity disorder (ADHD), CBCL internalizing, externalizing, or total problems scores, YGTSS scores, or GAF scores. The observed similarities in demographic features, clinical presentation, rates of ADHD and OCD/OCB, and global impairment may reflect similar phenomenology and illness-related characteristics of TD in these referred youth. Differences in age at initial specialty clinic evaluation and rates of ODD, mood and non-OCD anxiety disorders may need further exploration before they may be considered to reflect cultural factors. Because of these limitations (e.g. small sample size), these results can be regarded only as preliminary.

Safety and Efficacy of Long-Term Deutetrabenazine Use in Children and Adolescents with Tics Associated with Tourette Syndrome: An Open-Label Extension Study.

Background: Tourette syndrome (TS) is a neurodevelopmental disorder characterized by motor and phonic tics. Objective: To assess the safety and efficacy of deutetrabenazine (Teva Neuroscience, Inc, Parsippany, NJ), a vesicular monoamine transporter 2 inhibitor, in children and adolescents with TS. Methods: Alternatives for Reducing Tics in TS (ARTISTS) open-label extension (OLE) (NCT03567291) was a 54-week, global, phase 3, open-label extension study of deutetrabenazine (6-48 mg daily) conducted May 28, 2018 to April 3, 2020 with a 2-week randomized withdrawal period. Participants (6-16 years of age) had TS and active tics causing distress or impairment. Safety (primary outcome) was assessed by treatment-emergent adverse events (TEAEs) and clinical laboratory testing. Efficacy was measured by the Yale Global Tic Severity Scale-Total Tic Score (YGTSS-TTS). Results: The intent-to-treat population (228 participants; mean age, 12.0 years; 79.8% male; 86.4% white) had a median (range) duration of exposure of 28.4 (0.3-52.9) weeks. Of 227 participants in the safety analysis, 161 (70.9%) reported ≥1 TEAE (exposure-adjusted incidence rate, 2.77/patient-year), of which 95 (41.9%) were treatment related. The most frequently reported TEAEs were headaches, somnolence, nasopharyngitis, weight increases, and anxiety. No additional safety signals were observed. Worsening of YGTSS-TTS after the 2-week randomized withdrawal was not statistically significant (least squares mean difference, -0.4; P = 0.78). Several exploratory measures showed sustained improvement throughout the treatment periods. Conclusions: In this long-term, open-label trial, deutetrabenazine was well tolerated with low frequency of TEAEs. There was no significant difference in tics between treatment arms during the 2-week randomized withdrawal period, however, descriptive statistics and comparison with baseline showed a numeric improvement in tics, quality of life, and other measures.

Defects in acute responses to TLR4 in Btk-deficient mice result in impaired dendritic cell-induced IFN-γ production by natural killer cells.

This study defines a critical role for Btk in regulating TLR4-induced crosstalk between antigen presenting cells (APCs) and natural killer (NK) cells. Reduced levels of IL-12, IL-18 and IFN-γ were observed in Btk-deficient mice and ex vivo generated macrophages and dendritic cells (DCs) following acute LPS administration, whilst enhanced IL-10 production was observed. In addition, upregulation of activation markers and antigen presentation molecules on APCs was also impaired in the absence of Btk. APCs, by virtue of their ability to produce IL-12 and IL-18, are strong inducers of NK-derived IFN-γ. Co-culture experiments demonstrate that Btk-deficient DCs were unable to drive wild-type or Btk-deficient NK cells to induce IFN-γ production, whereas these responses could be restored by exogenous administration of IL-12 and IL-18. Thus Btk is a critical regulator of APC-induced NK cell activation by virtue of its ability to regulate IL-12 and IL-18 production in response to acute LPS administration.

A multicenter randomized placebo-controlled clinical trial of pramipexole for Tourette's syndrome.

BACKGROUND: Dopamine agonists could theoretically normalize the suspected central dopamine hypersensitivity in Tourette's syndrome. METHODS: There was a multicenter randomized, placebo-controlled, double-blind clinical trial of pramipexole given for 6 weeks in 63 children and adolescents with Tourette's syndrome. RESULTS: There were no significant differences in the adjusted mean change in the Total Tic Score of the Yale Global Tic Severity Scale for patients treated with pramipexole (-7.16) and placebo (-7.17). There were no significant treatment effects on change from baseline in the Global Severity score of the Yale Scale and parent- and investigator-scored Clinical Global Impression of Improvement. In patients with attention deficit hyperactivity disorder, there was improvement in DuPaul ADHD scale scores for patients receiving pramipexole compared with placebo. CONCLUSIONS: There was no evidence that pramipexole has efficacy in suppressing tics. Pramipexole may decrease symptoms of associated attention deficit hyperactivity disorder.

Tourette syndrome in youth with and without obsessive compulsive disorder and attention deficit hyperactivity disorder.

Chronic tic disorders (TD) are consistently found to have high rates of comorbidity with obsessive-compulsive disorder (OCD) and attention deficit hyperactivity disorder (ADHD). The purpose of this study is to compare the severity of TD only to TD with comorbid OCD or ADHD based on severity of tics, measures of psychopathology and additional comorbid diagnoses. Baseline data from 158 youth with a chronic TD who participated in two longitudinal studies were examined. Fifty-three percent (N = 85) of the youth also met criteria for a diagnosis of OCD, 38.6 % (n = 61) met criteria for ADHD and 24.1 % (N = 38) met criteria for both. Measures of interest addressed severity of tics, symptoms of anxiety, depression, ADHD, psychosocial stress, global functioning and the presence of comorbid diagnoses. Youth with comorbid TD and OCD were characterized by more severe tics, increased levels of depressive and anxious symptoms, heightened psychosocial stress and poorer global functioning. Youth with comorbid TD and ADHD did not differ from those with TD alone on measures of tic severity, but experienced greater psychosocial stress and poorer global functioning. Subjects with comorbid TD and OCD had more internalizing disorders than those without OCD, while those with comorbid ADHD were more likely to meet criteria for oppositional defiant disorder. TD with OCD is a more severe subtype of TD than TD without OCD. TD with ADHD is associated with higher psychosocial stress and more externalizing behaviors. Further research is needed into the underlying relationships between these closely associated conditions.

Pharmacologic Treatment of Comorbid Attention-Deficit/Hyperactivity Disorder and Tourette and Tic Disorders.

A complete and comprehensive medical and psychiatric evaluation is necessary to delineate tic symptoms from attention-deficit/hyperactivity disorder, and to prioritize the most problematic symptoms for intervention. Stimulants are the recommended first-line pharmacotherapy to treat attention-deficit/hyperactivity disorder symptoms in patients with tic disorders. Comprehensive behavioral intervention for tics is an effective behavioral therapy that is generally considered the first-line treatment of persistent tic disorders. α-Agonists can be added to stimulants if tics increase or be used as monotherapy to target attention-deficit/hyperactivity disorder and tics. Atomoxetine is also an excellent option to treat attention-deficit/hyperactivity disorder and tics.

Allopregnanolone: The missing link to explain the effects of stress on tic exacerbation?

The neurosteroid allopregnanolone (3α-hydroxy-5α-pregnan-20-one; AP) elicits pleiotropic effects in the central nervous system, ranging from neuroprotective and anti-inflammatory functions to the regulation of mood and emotional responses. Several lines of research show that the brain rapidly produces AP in response to acute stress to reduce the allostatic load and enhance coping. These effects not only are likely mediated by GABAA receptor activation but also result from the contributions of other mechanisms, such as the stimulation of membrane progesterone receptors. In keeping with this evidence, AP has been shown to exert rapid, potent antidepressant properties and has been recently approved for the therapy of moderate-to-severe postpartum depression. In addition to depression, emerging evidence points to the potential of AP as a therapy for other neuropsychiatric disorders, including anxiety, seizures, post-traumatic stress disorder and cognitive problems. Although this evidence has spurred interest in further therapeutic applications of AP, some investigations suggest that this neurosteroid may also be associated with adverse events in specific disorders. For example, our group has recently documented that AP increases tic-like manifestations in several animal models of tic disorders; furthermore, our results indicate that inhibiting AP synthesis and signalling reduces the exacerbation of tic severity associated with acute stress. Although the specific mechanisms of these effects remain partially elusive, our findings point to the possibility that the GABAergic activation by AP may also lead to disinhibitory effects, which could interfere with the ability of patients to suppress their tics. Future studies will be necessary to verify whether these mechanisms may apply to other externalising manifestations, such as impulse-control problems and manic symptoms.

Diagnosis and Management of Functional Tic-Like Phenomena.

Over the past 3 years, a global phenomenon has emerged characterized by the sudden onset and frequently rapid escalation of tics and tic-like movements and phonations. These symptoms have occurred not only in youth known to have tics or Tourette syndrome (TS), but also, and more notably, in youth with no prior history of tics. The Tourette Association of America (TAA) convened an international, multidisciplinary working group to better understand this apparent presentation of functional neurological disorder (FND) and its relationship to TS. Here, we review and summarize the literature relevant to distinguish the two, with recommendations to clinicians for diagnosis and management. Finally, we highlight areas for future emphasis and research.

Ticked Off: Anger Outbursts and Aggressive Symptoms in Tourette Disorder.

Tourette disorder is a complex neuropsychiatric syndrome of childhood onset characterized by multiple motor and phonic tics and is associated with high rates of psychiatric comorbidity. Symptoms of impulsive aggression (explosive outbursts or "rage") are commonly encountered in the clinical setting, cause significant morbidity, and pose diagnostic and treatment challenges. These symptoms may be multifactorial in etiology and result from a complex interplay of illness severity and psychosocial factors. Treatment strategies require careful differential diagnostic evaluation and include both behavioral and pharmacologic interventions.

Efficacy and Safety of Fixed-Dose Deutetrabenazine in Children and Adolescents for Tics Associated With Tourette Syndrome: A Randomized Clinical Trial.

Importance: Tourette syndrome is a neurodevelopmental disorder characterized by childhood onset of motor and phonic tics, often accompanied by behavioral and psychiatric comorbidities. Deutetrabenazine is a vesicular monoamine transporter 2 inhibitor approved in the US for the treatment of chorea associated with Huntington disease and tardive dyskinesia. Objective: To report results of the ARTISTS 2 (Alternatives for Reducing Tics in Tourette Syndrome 2) study examining deutetrabenazine for treatment of Tourette syndrome. Design, Setting, and Participants: This phase 3, randomized, double-blind, placebo-controlled, parallel-group, fixed-dose study was conducted over 8 weeks with a 1-week follow-up (June 21, 2018, to December 9, 2019). Children and adolescents aged 6 to 16 years with a diagnosis of Tourette syndrome and active tics causing distress or impairment were enrolled in the study. Children were recruited from 52 sites in 10 countries. Data were analyzed from February 4 to April 22, 2020. Interventions: Participants were randomized (1:1:1) to low-dose deutetrabenazine (up to 36 mg/d), high-dose deutetrabenazine (up to 48 mg/d), or a matching placebo, which were titrated over 4 weeks to the target dose followed by a 4-week maintenance period. Main Outcomes and Measures: The primary efficacy end point was change from baseline to week 8 in the Yale Global Tic Severity Scale-Total Tic Score (YGTSS-TTS) for high-dose deutetrabenazine. Key secondary end points included changes in YGTSS-TTS for low-dose deutetrabenazine, Tourette Syndrome Clinical Global Impression score, Tourette Syndrome Patient Global Impression of Impact score, and Child and Adolescent Gilles de la Tourette Syndrome-Quality of Life Activities of Daily Living subscale score. Safety assessments included incidence of treatment-emergent adverse events, laboratory parameters, vital signs, and questionnaires. Results: The study included 158 children and adolescents (mean [SD] age, 11.7 [2.6] years). A total of 119 participants (75%) were boys; 7 (4%), Asian; 1 (1%), Black; 32 (20%), Hispanic; 4 (3%), Native American; 135 (85%), White; 2 (1%), multiracial; 9 (6%), other race; and 1 (0.6%), of unknown ethnic origin. Fifty-two participants were randomized to the high-dose deutetrabenazine group, 54 to the low-dose deutetrabenazine group, and 52 to the placebo group. Baseline characteristics for participants were similar between groups. Of the total 158 participants, 64 (41%) were aged 6 to 11 years, and 94 (59%) were aged 12 to 16 years at baseline. Mean time since Tourette syndrome diagnosis was 3.3 (2.8) years, and mean baseline YGTSS-TTS was 33.8 (6.6) points. At week 8, the difference in YGTSS-TTS was not significant between the high-dose deutetrabenazine and placebo groups (least-squares mean difference, -0.8 points; 95% CI, -3.9 to 2.3 points; P = .60; Cohen d, -0.11). There were no nominally significant differences between groups for key secondary end points. Treatment-emergent adverse events were reported for 34 participants (65%) treated with high-dose deutetrabenazine, 24 (44%) treated with low-dose deutetrabenazine, and 25 (49%) treated with placebo and were generally mild or moderate. Conclusions and Relevance: In this fixed-dose randomized clinical trial of deutetrabenazine in children and adolescents with Tourette syndrome, the primary efficacy end point was not met. No new safety signals were identified. Trial Registration: ClinicalTrials.gov Identifier: NCT03571256.

Safety and Efficacy of Flexible-Dose Deutetrabenazine in Children and Adolescents With Tourette Syndrome: A Randomized Clinical Trial.

Importance: Tourette syndrome is a neurodevelopmental disorder characterized by childhood onset of motor and phonic tics; treatments for tics are associated with safety concerns. Deutetrabenazine is a selective vesicular monoamine transporter 2 inhibitor approved for the treatment of chorea associated with Huntington disease and tardive dyskinesia in adults. Objective: To examine whether deutetrabenazine is effective and safe for the treatment of Tourette syndrome in children and adolescents. Design, Setting, and Participants: This phase 2/3, randomized, double-masked, placebo-controlled, parallel-group, dose-titration study included children and adolescents (aged 6-16 years) with Tourette syndrome with active tics causing distress or impairment (ie, Yale Global Tic Severity Scale-Total Tic Score [YGTSS-TTS] ≥20). The trial was conducted over 12 weeks, with 1 week of follow-up from February 2018 to November 2019 at 36 centers in the United States, Canada, Denmark, Russia, Serbia, and Spain. Data analysis was conducted from January 31 to April 22, 2020. Intervention: Patients were randomized (1:1) to receive deutetrabenazine or placebo, titrated during 7 weeks to an optimal level, followed by a 5-week maintenance period. The maximum total daily deutetrabenazine dose was 48 mg/d. Main Outcomes and Measures: The primary efficacy end point was change from baseline to week 12 in YGTSS-TTS. Key secondary end points included changes in Tourette Syndrome-Clinical Global Impression, Tourette Syndrome-Patient Global Impression of Impact, and Child and Adolescent Gilles de la Tourette Syndrome-Quality of Life Activities of Daily Living subscale score. Safety was assessed based on treatment-emergent adverse events, vital signs, questionnaires, and laboratory parameters. Results: A total of 119 participants were randomized to deutetrabenazine (59 participants; mean [SD] age, 11.5 [2.5] years; 53 [90%] boys; 49 [83%] White; 3 [5%] Black) and placebo (60 participants; mean [SD] age, 11.5 [2.6] years; 51 [85%] boys; 53 [88%] White; 3 [5%] Black). At week 12, the difference in YGTSS-TTS score was not significant between deutetrabenazine and placebo (least squares mean difference, -0.7; 95% CI, -4.1 to 2.8; P = .69; Cohen d, -0.07). There were no nominally significant differences between groups for key secondary end points. Treatment-emergent adverse events were reported for 38 patients (66%) and 33 patients (56%) receiving deutetrabenazine and placebo, respectively, and were generally mild or moderate. Conclusions and Relevance: In this study of deutetrabenazine in children and adolescents with Tourette syndrome, the primary efficacy end point was not met. No new safety signals were identified. These results may be informative for future studies of treatments for tics in Tourette syndrome. Trial Registration: ClinicalTrials.gov Identifier: NCT03452943.

Synaptic processes and immune-related pathways implicated in Tourette syndrome.

Tourette syndrome (TS) is a neuropsychiatric disorder of complex genetic architecture involving multiple interacting genes. Here, we sought to elucidate the pathways that underlie the neurobiology of the disorder through genome-wide analysis. We analyzed genome-wide genotypic data of 3581 individuals with TS and 7682 ancestry-matched controls and investigated associations of TS with sets of genes that are expressed in particular cell types and operate in specific neuronal and glial functions. We employed a self-contained, set-based association method (SBA) as well as a competitive gene set method (MAGMA) using individual-level genotype data to perform a comprehensive investigation of the biological background of TS. Our SBA analysis identified three significant gene sets after Bonferroni correction, implicating ligand-gated ion channel signaling, lymphocytic, and cell adhesion and transsynaptic signaling processes. MAGMA analysis further supported the involvement of the cell adhesion and trans-synaptic signaling gene set. The lymphocytic gene set was driven by variants in FLT3, raising an intriguing hypothesis for the involvement of a neuroinflammatory element in TS pathogenesis. The indications of involvement of ligand-gated ion channel signaling reinforce the role of GABA in TS, while the association of cell adhesion and trans-synaptic signaling gene set provides additional support for the role of adhesion molecules in neuropsychiatric disorders. This study reinforces previous findings but also provides new insights into the neurobiology of TS.