The Challenge of Examining Social Determinants of Health in People Living With Tourette Syndrome.

BACKGROUND: To examine the association between race, ethnicity, and parental educational attainment on tic-related outcomes among Tourette Syndrome (TS) participants in the Tourette Association of America International Consortium for Genetics (TAAICG) database. METHODS: 723 participants in the TAAICG dataset aged ≤21 years were included. The relationships between tic-related outcomes and race and ethnicity were examined using linear and logistic regressions. Parametric and nonparametric tests were performed to examine the association between parental educational attainment and tic-related outcomes. RESULTS: Race and ethnicity were collapsed as non-Hispanic white (N=566, 88.0%) versus Other (N=77, 12.0%). Tic symptom onset was earlier by 1.1 years (P < 0.0001) and TS diagnosis age was earlier by 0.9 years (P = 0.0045) in the Other group (versus non-Hispanic white). Sex and parental education as covariates did not contribute to the differences observed in TS diagnosis age. There were no significant group differences observed across the tic-related outcomes in parental education variable. CONCLUSIONS: Our study was limited by the low number of nonwhite or Hispanic individuals in the cohort. Racial and ethnic minoritized groups experienced an earlier age of TS diagnosis than non-Hispanic white individuals. Tic severity did not differ between the two groups, and parental educational attainment did not affect tic-related outcomes. There remain significant disparities and gaps in knowledge regarding TS and associated comorbid conditions. Our study suggests the need for more proactive steps to engage individuals with tic disorders from all racial and ethnic minoritized groups to participate in research studies.

Sex Differences in People with Tourette Syndrome and Persistent Motor or Vocal Tic Disorder in the Tourette Association of America International Consortium for Genetics Database.

Background and Objective: Tourette Syndrome (TS) and Persistent Motor or Vocal Tic Disorders (PMVT) are more prevalent in males (vs. females). Females with TS may have a delay in diagnosis, and more complex tic features (vs. males). With respect to comorbidities, obsessive-compulsive disorder (OCD) is more prevalent in females; attention-deficit hyperactivity disorder (ADHD) is more prevalent in males. Less is known about sex differences in PMVT. This study analyzes sex differences in outcomes among individuals with TS and PMVT in the Tourette Association of America International Consortium for Genetics dataset (TAAICG). Design/Methods: Data from 2403 individuals (N=2109 TS; N=294 PMVT) from the TAAICG were analyzed to explore the relationship between sex and TS or PMVT outcomes: age at tic onset; age at diagnosis; time-to-diagnosis; tic severity; and comorbidity rates. Regression models were adjusted for age and family relationships to examine the impact of sex on outcomes. Results: Females with TS (25.5% of the sample) had a later age of symptom onset (6.5±2.8 vs. 6.0±2.7; p=0.001), later age at diagnosis (13.3±11.2 vs. 10.7±8.1; p=0.0001), and a longer time-to-diagnosis [3 (1,7) vs. 2 (1,5), p=0.01] than males. The total Yale-Global Tic Severity Scale (YGTSS) was lower in females with TS (28.4±9.1 vs. 30.7±8.7); p<0.0001); OCD was slightly more prevalent in females (55% vs. 48.7%; p=0.01) although OCD severity did not differ by sex; ADHD was more prevalent in males (55.7% vs 38.9%; p<0.001). Females with TS had 0.46 lower odds of being diagnosed with TS (p<0.00001). Females with PMVT (42.9% of the sample) had an earlier age of symptom onset (7.9±3.3 vs. 8.9±3.7; p=0.05). Motor or vocal tic severity (YGTSS) was not significantly different. OCD, but not ADHD, was more prevalent in females (OCD: 41.9% vs. 22.2%; p<0.001: ADHD:16.5% vs 21.0%; p=0.4). Conclusion: Females with TS are less likely to be formally diagnosed and have a later age of symptom onset, later age at diagnosis, longer time-to-diagnosis, higher prevalence of OCD, and lower prevalence of ADHD (vs. males). Females with PMVT have an earlier age of symptom onset, higher prevalence of OCD, but similar ADHD prevalence rates (vs. males). Females with TS and PMVT may be clinically different than males with TS. Future research is needed to understand differences longitudinally in TS and PMVT.

Oral diadochokinetic markers of X-linked dystonia-parkinsonism.

INTRODUCTION: X-linked dystonia-parkinsonism (XDP) is a neurodegenerative disorder that may result in severe speech impairment. The literature suggests that there are differences in the speech of individuals with XDP and healthy controls. This study aims to examine the motor speech characteristics of the mixed dystonia-parkinsonism phase of XDP. METHOD: We extracted acoustic features representing coordination, consistency, speed, precision, and rate from 26 individuals with XDP and 26 controls using Praat, MATLAB, and R software. Group demographics were compared using descriptive statistics. A one-way analysis of variance (ANOVA) with Tukey's post hoc test was used to test for acoustic differences between the two groups. RESULTS: The XDP group had significantly lower consistency, speed, precision, and rate than controls (p < 0.05). For coordination, the XDP group had a smaller ratio of pause duration during transitions when compared to controls. DISCUSSION: To our knowledge, this study is the first to describe the motor speech characteristics of the mixed dystonia-parkinsonism phase of XDP. The motor speech of mixed dystonia-parkinsonism XDP is similar to prior characterizations of mixed hyperkinetic-hypokinetic dysarthria with noted differences in articulatory coordination, consistency, speed, precision, and rate from healthy controls. Identifying the motor speech components of all three phenotypes of XDP (i.e., dystonia-dominant phase, parkinsonism-dominant phase, and mixed dystonia-parkinsonism phase) is needed to establish markers of speech impairment to track disease progression.

In humans, striato-pallido-thalamic projections are largely segregated by their origin in either the striosome-like or matrix-like compartments.

Cortico-striato-thalamo-cortical (CSTC) loops are fundamental organizing units in mammalian brains. CSTCs process limbic, associative, and sensorimotor information in largely separated but interacting networks. CTSC loops pass through paired striatal compartments, striosome (aka patch) and matrix, segregated pools of medium spiny projection neurons with distinct embryologic origins, cortical/subcortical structural connectivity, susceptibility to injury, and roles in behaviors and diseases. Similarly, striatal dopamine modulates activity in striosome and matrix in opposite directions. Routing CSTCs through one compartment may be an anatomical basis for regulating discrete functions. We used differential structural connectivity, identified through probabilistic diffusion tractography, to distinguish the striatal compartments (striosome-like and matrix-like voxels) in living humans. We then mapped compartment-specific projections and quantified structural connectivity between each striatal compartment, the globus pallidus interna (GPi), and 20 thalamic nuclei in 221 healthy adults. We found that striosome-originating and matrix-originating streamlines were segregated within the GPi: striosome-like connectivity was significantly more rostral, ventral, and medial. Striato-pallido-thalamic streamline bundles that were seeded from striosome-like and matrix-like voxels transited spatially distinct portions of the white matter. Matrix-like streamlines were 5.7-fold more likely to reach the GPi, replicating animal tract-tracing studies. Striosome-like connectivity dominated in six thalamic nuclei (anteroventral, central lateral, laterodorsal, lateral posterior, mediodorsal-medial, and medial geniculate). Matrix-like connectivity dominated in seven thalamic nuclei (centromedian, parafascicular, pulvinar-anterior, pulvinar-lateral, ventral lateral-anterior, ventral lateral-posterior, ventral posterolateral). Though we mapped all thalamic nuclei independently, functionally-related nuclei were matched for compartment-level bias. We validated these results with prior thalamostriate tract tracing studies in non-human primates and other species; where reliable data was available, all agreed with our measures of structural connectivity. Matrix-like connectivity was lateralized (left > right hemisphere) in 18 thalamic nuclei, independent of handedness, diffusion protocol, sex, or whether the nucleus was striosome-dominated or matrix-dominated. Compartment-specific biases in striato-pallido-thalamic structural connectivity suggest that routing CSTC loops through striosome-like or matrix-like voxels is a fundamental mechanism for organizing and regulating brain networks. Our MRI-based assessments of striato-thalamic connectivity in humans match and extend the results of prior tract tracing studies in animals. Compartment-level characterization may improve localization of human neuropathologies and improve neurosurgical targeting in the GPi and thalamus.

Establishing a natural history of X-linked dystonia parkinsonism.

X-linked dystonia parkinsonism is a neurodegenerative movement disorder that affects men whose mothers originate from the island of Panay, Philippines. Current evidence indicates that the most likely cause is an expansion in the TAF1 gene that may be amenable to treatment. To prepare for clinical trials of therapeutic candidates for X-linked dystonia parkinsonism, we focused on the identification of quantitative phenotypic measures that are most strongly associated with disease progression. Our main objective is to establish a comprehensive, quantitative assessment of movement dysfunction and bulbar motor impairments that are sensitive and specific to disease progression in persons with X-linked dystonia parkinsonism. These measures will set the stage for future treatment trials. We enrolled patients with X-linked dystonia parkinsonism and performed a comprehensive oromotor, speech and neurological assessment. Measurements included patient-reported questionnaires regarding daily living activities and both neurologist-rated movement scales and objective quantitative measures of bulbar function and nutritional status. Patients were followed for 18 months from the date of enrollment and evaluated every 6 months during that period. We analysed a total of 87 men: 29 were gene-positive and had symptoms at enrollment, seven were gene-positive and had no symptoms at enrollment and 51 were gene-negative. We identified measures that displayed a significant change over the study. We used principal variables analysis to identify a minimal battery of 21 measures that explains 67.3% of the variance over the course of the study. These measures included patient-reported, clinician-rated and objective quantitative outcomes that may serve as endpoints in future clinical trials.

Sustained activation in basal ganglia and cerebellum after repetitive movement in a non-task-specific dystonia.

We previously observed sustained fMRI BOLD signal in the basal ganglia in focal hand dystonia patients after a repetitive finger tapping task. Since this was observed in a task-specific dystonia, for which excessive task repetition may play a role in pathogenesis, in the current study we asked if this effect would be observed in a focal dystonia (cervical dystonia [CD]) that is not considered task-specific or thought to result from overuse. We evaluated fMRI BOLD signal time courses before, during, and after the finger tapping task in CD patients. We observed patient/control differences in post-tapping BOLD signal in left putamen and left cerebellum during the non-dominant (left) hand tapping condition, reflecting abnormally sustained BOLD signal in CD. BOLD signals in left putamen and cerebellum were also abnormally elevated in CD during tapping itself and escalated as tapping was repeated. There were no cerebellar differences in the previously studied FHD cohort, either during or after tapping. We conclude that some elements of pathogenesis and/or pathophysiology associated with motor task execution/repetition may not be limited to task-specific dystonias, but there may be regional differences in these effects across dystonias, associated with different types of motor control programs.

Dystonias: Clinical Recognition and the Role of Additional Diagnostic Testing.

Dystonia is the third most common movement disorder, characterized by abnormal, frequently twisting postures related to co-contraction of agonist and antagonist muscles. Diagnosis is challenging. We provide a comprehensive appraisal of the epidemiology and an approach to the phenomenology and classification of dystonia, based on the clinical characteristics and underlying etiology of dystonia syndromes. We discuss the features of common idiopathic and genetic forms of dystonia, diagnostic challenges, and dystonia mimics. Appropriate workup is based on the age of symptom onset, rate of progression, whether dystonia is isolated or combined with another movement disorder or complex neurological and other organ system features. Based on these features, we discuss when imaging and genetic should be considered. We discuss the multidisciplinary treatment of dystonia, including rehabilitation and treatment principles according to the etiology, including when pathogenesis-direct treatment is available, oral pharmacological therapy, chemodenervation with botulinum toxin injections, deep brain stimulation and other surgical therapies, and future directions.

A novel gain of function mutation in TPC2 reiterates pH-pigmentation interplay: Emerging role of ionic homeostasis as a master pigmentation regulator.

Pigmentation is a complex physiological phenomenon that protects from UV induced damage. Perturbations in pigmentation pathways lead to pigmentary disorders such as vitiligo, albinism and Darier...s disease. Emerging literature implicates a critical role of ionic homeostasis and pH in regulating pigmentation. In a recent study, Wang et al. identified a novel gain of function mutation in a non-selective cation channel "Two Pore Channel 2" (TPC2) that is responsible for albinism in a human patient. The authors demonstrate that this mutation leads to constitutive activation of TPC2 thereby modulating cellular calcium dynamics and inducing changes in the lysosomal pH. Further, authors generated a knock in mice with homologous TPC2 mutation and corroborated a causative role for this mutation in albinism. It is an exciting study that reports a novel TPC2 mutation, which is responsible for albinism in an autosomal dominant inheritance fashion. Since TPC2 is localized on melanosomes as well, going forward it would be interesting to investigate the role of this mutation on melanosomal calcium dynamics and alterations in melanosomal pH.

Progressive Decline in Voice and Voice-Related Quality of Life in X-Linked Dystonia Parkinsonism.

OBJECTIVE: To characterize the evolution of swallowing and voice in patients with X-linked dystonia parkinsonism (XDP). STUDY DESIGN: Retrospective case series. METHODS: Retrospective review of 59 patients with XDP from January 2016 to January 2018. All patients underwent complete examinations and quality of life (QOL) surveys (Swallowing Quality of Life questionnaire [SWAL-QOL], Voice-Related Quality of Life [V-RQOL], and Voice Handicap Index [VHI]), and functional endoscopic examination of swallowing. We excluded patients with incomplete records or patients lost to follow-up. Univariate analysis was used to compare 2016 to 2018 Penetration-Aspiration Scale (PAS), SWAL-QOL, V-RQOL, and VHI scores. RESULTS: Ten patients met the inclusion criteria. Nine patients had oromandibular dystonia. Voice-related measures significantly worsened with an increase in mean VHI from 81 to 109.9 (P = 0.026) and decrease in mean V-RQOL from 58 to 28 (P = 0.013). Vocal strain also significantly worsened 0.4 to 1.4 (P = 0.001). Mean PAS scores increased from 4.2 to 5.1 (P = 0.068) and mean SWAL-QOL decreased from 50.4 to 43.5 (P = 0.157). In the SWAL-QOL, the mean Eating Duration score worsened from 0.9 to 0.4 (P = 0.052) and Mental Health score declined from 10.1 to 6.1 (P = 0.077). CONCLUSIONS: Both vocal strain and voice-related QOL measures considerably worsened over the 2-year interval in our limited group of XDP patients with no significant change in PAS scores or swallowing QOL. The findings demonstrated that the pace of disease affecting voice symptoms was different from swallowing symptoms in our study group and that changes in communication ability may be a more sensitive marker for disease progression than swallowing dysfunction.

Functional validation of novel variants in B4GALNT1 associated with early-onset complex hereditary spastic paraplegia with impaired ganglioside synthesis.

Childhood-onset forms of hereditary spastic paraplegia are ultra-rare diseases and often present with complex features. Next-generation-sequencing allows for an accurate diagnosis in many cases but the interpretation of novel variants remains challenging, particularly for missense mutations. Where sufficient knowledge of the protein function and/or downstream pathways exists, functional studies in patient-derived cells can aid the interpretation of molecular findings. We here illustrate the case of a 13-year-old female who presented with global developmental delay and later mild intellectual disability, progressive spastic diplegia, spastic-ataxic gait, dysarthria, urinary urgency, and loss of deep tendon reflexes of the lower extremities. Exome sequencing showed a novel splice-site variant in trans with a novel missense variant in B4GALNT1 [NM_001478.5: c.532-1G>C/c.1556G>C (p.Arg519Pro)]. Functional studies in patient-derived fibroblasts and cell models of GM2 synthase deficiency confirmed a loss of B4GALNT1 function with no synthesis of GM2 and other downstream gangliosides. Collectively these results established the diagnosis of B4GALNT1-associated HSP (SPG26). Our approach illustrates the importance of careful phenotyping and functional characterization of novel gene variants, particularly in the setting of ultra-rare diseases, and expands the clinical and molecular spectrum of SPG26, a disorder of complex ganglioside biosynthesis.

DYT-PRKRA Mutation P222L Enhances PACT's Stimulatory Activity on Type I Interferon Induction.

DYT-PRKRA (dystonia 16 or DYT-PRKRA) is caused by mutations in the PRKRA gene that encodes PACT, the protein activator of interferon (IFN)-induced double-stranded (ds) RNA-activated protein kinase (PKR). PACT participates in several cellular pathways, of which its role as a PKR activator protein during integrated stress response (ISR) is the best characterized. Previously, we have established that the DYT-PRKRA mutations cause enhanced activation of PKR during ISR to sensitize DYT-PRKRA cells to apoptosis. In this study, we evaluate if the most prevalent substitution mutation reported in DYT-PRKRA patients alters PACT's functional role in induction of type I IFNs via the retinoic acid-inducible gene I (RIG-I) signaling. Our results indicate that the P222L mutation augments PACT's ability to induce IFN ß in response to dsRNA and the basal expression of IFN ß and IFN-stimulated genes (ISGs) is higher in DYT-PRKRA patient cells compared to cells from the unaffected controls. Additionally, IFN ß and ISGs are also induced at higher levels in DYT-PRKRA cells in response to dsRNA. These results offer a new avenue for investigations directed towards understanding the underlying molecular pathomechanisms in DYT-PRKRA.

Tissue-specific and repeat length-dependent somatic instability of the X-linked dystonia parkinsonism-associated CCCTCT repeat.

X-linked dystonia-parkinsonism (XDP) is a progressive adult-onset neurodegenerative disorder caused by insertion of a SINE-VNTR-Alu (SVA) retrotransposon in the TAF1 gene. The SVA retrotransposon contains a CCCTCT hexameric repeat tract of variable length, whose length is inversely correlated with age at onset. This places XDP in a broader class of repeat expansion diseases, characterized by the instability of their causative repeat mutations. Here, we observe similar inverse correlations between CCCTCT repeat length with age at onset and age at death and no obvious correlation with disease duration. To gain insight into repeat instability in XDP we performed comprehensive quantitative analyses of somatic instability of the XDP CCCTCT repeat in blood and in seventeen brain regions from affected males. Our findings reveal repeat length-dependent and expansion-based instability of the XDP CCCTCT repeat, with greater levels of expansion in brain than in blood. The brain exhibits regional-specific patterns of instability that are broadly similar across individuals, with cerebellum exhibiting low instability and cortical regions exhibiting relatively high instability. The spectrum of somatic instability in the brain includes a high proportion of moderate repeat length changes of up to 5 repeats, as well as expansions of ~ 20- > 100 repeats and contractions of ~ 20-40 repeats at lower frequencies. Comparison with HTT CAG repeat instability in postmortem Huntington's disease brains reveals similar brain region-specific profiles, indicating common trans-acting factors that contribute to the instability of both repeats. Analyses in XDP brains of expansion of a different SVA-associated CCCTCT located in the LIPG gene, and not known to be disease-associated, reveals repeat length-dependent expansion at overall lower levels relative to the XDP CCCTCT repeat, suggesting that expansion propensity may be modified by local chromatin structure. Together, the data support a role for repeat length-dependent somatic expansion in the process(es) driving the onset of XDP and prompt further investigation into repeat dynamics and the relationship to disease.

Orai3 Regulates Pancreatic Cancer Metastasis by Encoding a Functional Store Operated Calcium Entry Channel.

Store operated Ca2+ entry (SOCE) mediated by Orai1/2/3 channels is a highly regulated and ubiquitous Ca2+ influx pathway. Although the role of Orai1 channels is well studied, the significance of Orai2/3 channels is still emerging in nature. In this study, we performed extensive bioinformatic analysis of publicly available datasets and observed that Orai3 expression is inversely associated with the mean survival time of PC patients. Orai3 expression analysis in a battery of PC cell lines corroborated its differential expression profile. We then carried out thorough Ca2+ imaging experiments in six PC cell lines and found that Orai3 forms a functional SOCE channel in PC cells. Our in vitro functional assays show that Orai3 regulates PC cell cycle progression, apoptosis and migration. Most importantly, our in vivo xenograft studies demonstrate a critical role of Orai3 in PC tumor growth and secondary metastasis. Mechanistically, Orai3 controls G1 phase progression, matrix metalloproteinase expression and epithelial-mesenchymal transition in PC cells. Taken together, this study for the first-time reports that Orai3 drives aggressive phenotypes of PC cells, i.e., migration in vitro and metastasis in vivo. Considering that Orai3 overexpression leads to poor prognosis in PC patients, it appears to be a highly attractive therapeutic target.

Dystonia-specific mutations in THAP1 alter transcription of genes associated with neurodevelopment and myelin.

Dystonia is a neurologic disorder associated with an increasingly large number of genetic variants in many genes, resulting in characteristic disturbances in volitional movement. Dissecting the relationships between these mutations and their functional outcomes is critical in understanding the pathways that drive dystonia pathogenesis. Here we established a pipeline for characterizing an allelic series of dystonia-specific mutations. We used this strategy to investigate the molecular consequences of genetic variation in THAP1, which encodes a transcription factor linked to neural differentiation. Multiple pathogenic mutations associated with dystonia cluster within distinct THAP1 functional domains and are predicted to alter DNA-binding properties and/or protein interactions differently, yet the relative impact of these varied changes on molecular signatures and neural deficits is unclear. To determine the effects of these mutations on THAP1 transcriptional activity, we engineered an allelic series of eight alterations in a common induced pluripotent stem cell background and differentiated these lines into a panel of near-isogenic neural stem cells (n = 94 lines). Transcriptome profiling followed by joint analysis of the most robust signatures across mutations identified a convergent pattern of dysregulated genes functionally related to neurodevelopment, lysosomal lipid metabolism, and myelin. On the basis of these observations, we examined mice bearing Thap1-disruptive alleles and detected significant changes in myelin gene expression and reduction of myelin structural integrity relative to control mice. These results suggest that deficits in neurodevelopment and myelination are common consequences of dystonia-associated THAP1 mutations and highlight the potential role of neuron-glial interactions in the pathogenesis of dystonia.

Speech and swallowing deficits in X-Linked Dystonia-Parkinsonism.

INTRODUCTION: X-linked Dystonia-Parkinsonism (XDP) is a progressive, disabling disease characterized by the devastating impairment of bulbar function, including speech and swallowing. Despite these detrimental impacts, bulbar impairments in this population are not well characterized. OBJECTIVES: To identify impairments in the bulbar system measured by oromotor performance in individuals with XDP relative to healthy controls. Secondarily, to detect diagnostic bulbar markers that are sensitive and specific to the initial years of XDP. METHODS: This case-control study included 25 healthy controls and 30 participants with XDP, divided into two subgroups based on the median of their disease length. Multiple clinical and instrumental oromotor tasks and measures were used to evaluate bulbar motor function. RESULTS: Differences were found between both the subgroups with XDP and healthy controls on almost all measures, including maximum performance tasks such as tongue strength, alternating motion rate (AMR), and sequential motion rate (SMR) (p < 0.05). Differences were found between the XDP subgroups and the control group for the percentage of pause time during the speech, a rating of speech severity, and a swallowing task (ps < 0.05). Scores on self-reported questionnaires, tongue strength, the number of repetitions produced during an AMR, percent pause, and speech severity demonstrated good sensitivity and specificity to differentiate the initial years of XDP onset from healthy controls. CONCLUSIONS: Our findings revealed impairments across bulbar functions in participants within the first 7 years of the XDP onset. Highly sensitive and specific bulbar impairment measures were detected in instrumental and self-reported measures that are fundamental for monitoring disease.

Identifying genetic modifiers of age-associated penetrance in X-linked dystonia-parkinsonism.

X-linked dystonia-parkinsonism is a neurodegenerative disorder caused by a founder retrotransposon insertion, in which a polymorphic hexanucleotide repeat accounts for ~50% of age at onset variability. Employing a genome-wide association study to identify additional factors modifying age at onset, we establish that three independent loci are significantly associated with age at onset (p < 5 × 10-8). The lead single nucleotide polymorphisms collectively account for 25.6% of the remaining variance not explained by the hexanucleotide repeat and 13.0% of the overall variance in age at onset in X-linked dystonia-parkinsonism with the protective alleles delaying disease onset by seven years. These regions harbor or lie adjacent to MSH3 and PMS2, the genes that were recently implicated in modifying age at onset in Huntington's disease, likely through a common pathway influencing repeat instability. Our work indicates the existence of three modifiers of age at onset in X-linked dystonia-parkinsonism that likely affect the DNA mismatch repair pathway.

Hyperkinetic Movements in Children: Differential Diagnosis, Evaluation, and Treatment.

The Psychiatric Consultation Service at Massachusetts General Hospital sees medical and surgical inpatients with comorbid psychiatric symptoms and conditions. During their twice-weekly rounds, Dr Stern and other members of the Consultation Service discuss diagnosis and management of hospitalized patients with complex medical or surgical problems who also demonstrate psychiatric symptoms or conditions. These discussions have given rise to rounds reports that will prove useful for clinicians practicing at the interface of medicine and psychiatry.