Genomic architecture differences at the HTT locus associated with symptomatic and pre-symptomatic cases of Huntington’s disease in a pilot study.

Background:Huntington’s disease (HD) is a progressive neurodegenerative condition that causes degeneration of neurons in the brain, ultimately leading to death. The root cause of HD is an expanded trinucleotide cytosine-adenine-guanine (CAG) repeat in the “huntingtin gene” (HTT). While there is a rough correlation between the number of CAG repeats and disease onset, the development of clinical symptoms can vary by decades within individuals and little is known about this pre-symptomatic phase.Methods:Using peripheral blood samples from HD patients and healthy controls we usedEpiSwitch™, a validated high-resolution industrial platform for the detection of chromosome conformations, to assess chromatin architecture in the immediate vicinity of theHTTgene. We evaluated chromatin conformations at 20 sites across 225 kb of theHTTlocus in a small cohort of healthy controls, verified symptomatic HD patients (CAG, n>39) and patients with CAG expansions who had not yet manifested clinical symptoms of HD.Results:Discrete chromosome conformations were observed across the patient groups. We found two constitutive interactions (occurring in all patient groups) and seven conditional interactions which were present in HD, but not in healthy controls. Most important, we observed three conditional interactions that were present only in HD patients manifesting clinical symptoms (symptomatic cases), but not in presymptomatic cases. Of the patients in the symptomatic HD cohort, 86% (6 out of 7) demonstrated at least one of the specific chromosome conformations associated with symptomatic HD.Conclusion:Our results provide the first evidence that chromatin architecture at theHTTlocus is systemically altered in patients with HD, with conditional differences between clinical stages. Given the high clinical need in having a molecular tool to assess disease progression in HD, these results strongly suggest that the non-invasive assessment of chromosome conformation signatures warrant further study as a prognostic tool in HD.

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Genomic architecture differences at the HTT locus associated with symptomatic and pre-symptomatic cases of Huntington’s disease in a pilot study

Edelweiss Psychiatry Open Access ◽

10.33805/2638-8073.131 ◽

2021 ◽

pp. 1-6

Author(s):

Matthew Salter ◽

Ryan Powell ◽

Jennifer Back ◽

Francis Grand ◽

Christina Koutsothanasi ◽

...

Keyword(s):

Huntington's Disease ◽

Huntington’S Disease ◽

Clinical Symptoms ◽

Disease Onset ◽

Cag Repeat ◽

Cag Repeats ◽

Healthy Controls ◽

Chromosome Conformation ◽

Chromatin Architecture ◽

Patient Groups

Huntington’s Disease (HD) is a progressive neurodegenerative condition that causes degeneration of neurons in the brain, ultimately leading to death. The root cause of HD is an expanded trinucleotide Cytosine-Adenine-Guanine (CAG) repeat in the “huntingtin gene” (HTT). While there is a rough correlation between the number of CAG repeats and disease onset, the development of clinical symptoms can vary by decades within individuals and little is known about this presymptomatic phase. Using peripheral blood samples from HD patients and healthy controls we used EpiSwitch®, a validated high-resolution industrial platform for the detection of chromosome conformations, to assess chromatin architecture in the immediate vicinity of the HTT gene. We evaluated chromatin conformations at 20 sites across 225 kb of the HTT locus in a small cohort of healthy controls, verified symptomatic HD patients (CAG, n>39) and patients with CAG expansions who had not yet manifested clinical symptoms of HD. Discrete chromosome conformations were observed across the patient groups. We found two constitutive interactions (occurring in all patient groups) and seven conditional interactions which were present in HD, but not in healthy controls. Most important, we observed three conditional interactions that were present only in HD patients manifesting clinical symptoms (symptomatic cases), but not in presymptomatic cases. 85% (6 out of 7) of the patients in the symptomatic HD cohort demonstrated at least one of the specific chromosome conformations associated with symptomatic HD. Our results provide the first evidence that chromatin architecture at the HTT locus is systemically altered in patients with HD, with conditional differences between clinical stages. Given the high clinical need in having a molecular tool to assess disease progression in HD, these results strongly suggest that the non-invasive assessment of Chromosome Conformation Signatures (CCS) warrant further study as a prognostic tool in HD.

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Genomic architecture differences at the HTT locus underlie symptomatic and pre-symptomatic cases of Huntington’s disease.

F1000Research ◽

10.12688/f1000research.15828.2 ◽

2019 ◽

Vol 7 ◽

pp. 1757

Author(s):

Matthew Salter ◽

Ryan Powell ◽

Jennifer Back ◽

Francis Grand ◽

Christina Koutsothanasi ◽

...

Keyword(s):

Huntington's Disease ◽

Huntington’S Disease ◽

Clinical Symptoms ◽

Disease Onset ◽

Cag Repeat ◽

Cag Repeats ◽

Healthy Controls ◽

Chromosome Conformation ◽

Chromatin Architecture ◽

Patient Groups

Background:Huntington’s disease (HD) is a progressive neurodegenerative condition that causes degeneration of neurons in the brain, ultimately leading to death. The root cause of HD is an expanded trinucleotide cytosine-adenine-guanine (CAG) repeat in the “huntingtin gene” (HTT). While there is a rough correlation between the number of CAG repeats and disease onset, the development of clinical symptoms can vary by decades within individuals and little is known about this pre-symptomatic phase.Methods:Using peripheral blood samples from HD patients and healthy controls we usedEpiSwitch™, a validated high-resolution industrial platform for the detection of chromosome conformations, to assess chromatin architecture in the immediate vicinity of theHTTgene. We evaluated chromatin conformations at 20 sites across 225 kb of theHTTlocus in healthy controls, verified symptomatic HD patients (CAG, n>39) and patients with CAG expansions who had not yet manifested clinical symptoms of HD.Results:Discrete chromosome conformations were observed across the patient groups. We found two constitutive interactions (occurring in all patient groups) and seven conditional interactions which were present in HD, but not in healthy controls. Most important, we observed three conditional interactions that were present only in HD patients manifesting clinical symptoms (symptomatic cases), but not in presymptomatic cases. Of the patients in the symptomatic HD cohort, 86% (6 out of 7) demonstrated at least one of the specific chromosome conformations associated with symptomatic HD.Conclusion:Our results provide the first evidence that chromatin architecture at theHTTlocus is systemically altered in patients with HD, with conditional differences between clinical stages. Given the high clinical need in having a molecular tool to assess disease progression in HD, these results strongly suggest that the non-invasive assessment of chromosome conformation signatures can be a valuable addition to prognostic assessment of HD patients.

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Genomic architecture differences at the HTT locus underlie symptomatic and pre-symptomatic cases of Huntington’s disease.

F1000Research ◽

10.12688/f1000research.15828.1 ◽

2018 ◽

Vol 7 ◽

pp. 1757 ◽

Cited By ~ 1

Author(s):

Matthew Salter ◽

Ryan Powell ◽

Jennifer Back ◽

Francis Grand ◽

Christina Koutsothanasi ◽

...

Keyword(s):

Huntington's Disease ◽

Huntington’S Disease ◽

Clinical Symptoms ◽

Disease Onset ◽

Cag Repeat ◽

Cag Repeats ◽

Healthy Controls ◽

Chromosome Conformation ◽

Chromatin Architecture ◽

Patient Groups

Background:Huntington’s disease (HD) is a progressive neurodegenerative condition that causes degeneration of neurons in the brain, ultimately leading to death. The root cause of HD is an expanded trinucleotide cytosine-adenine-guanine (CAG) repeat in the “huntingtin gene” (HTT). While there is a rough correlation between the number of CAG repeats and disease onset, the development of clinical symptoms can vary by decades within individuals and little is known about this pre-symptomatic phase.Methods:Using peripheral blood samples from HD patients and healthy controls we usedEpiSwitch™, a validated high-resolution industrial platform for the detection of chromosome conformations, to assess chromatin architecture in the immediate vicinity of theHTTgene. We evaluated chromatin conformations at 20 sites across 225 kb of theHTTlocus in healthy controls, verified symptomatic HD patients (CAG, n>39) and patients with CAG expansions who had not yet manifested clinical symptoms of HD.Results:Discrete chromosome conformations were observed across the patient groups. We found two constitutive interactions (occurring in all patient groups) and seven conditional interactions which were present in HD, but not in healthy controls. Most important, we observed three conditional interactions that were present only in HD patients manifesting clinical symptoms (symptomatic cases), but not in presymptomatic cases. Of the patients in the symptomatic HD cohort, 86% (6 out of 7) demonstrated at least one of the specific chromosome conformations associated with symptomatic HD.Conclusion:Our results provide the first evidence that chromatin architecture at theHTTlocus is systemically altered in patients with HD, with conditional differences between clinical stages. Given the high clinical need in having a molecular tool to assess disease progression in HD, these results strongly suggest that the non-invasive assessment of chromosome conformation signatures can be a valuable addition to prognostic assessment of HD patients.

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Predicting Disease Onset from Mutation Status Using Proband and Relative Data with Applications to Huntington's Disease

Journal of Probability and Statistics ◽

10.1155/2012/375935 ◽

2012 ◽

Vol 2012 ◽

pp. 1-19 ◽

Cited By ~ 3

Author(s):

Tianle Chen ◽

Yuanjia Wang ◽

Yanyuan Ma ◽

Karen Marder ◽

Douglas R. Langbehn

Keyword(s):

Huntington's Disease ◽

Huntington’S Disease ◽

Family Member ◽

Disease Onset ◽

Repeat Length ◽

Cag Repeat ◽

Cag Repeats ◽

Observational Research ◽

Accurate Estimation ◽

Combined Data

Huntington's disease (HD) is a progressive neurodegenerative disorder caused by an expansion of CAG repeats in the IT15 gene. The age-at-onset (AAO) of HD is inversely related to the CAG repeat length and the minimum length thought to cause HD is 36. Accurate estimation of the AAO distribution based on CAG repeat length is important for genetic counseling and the design of clinical trials. In the Cooperative Huntington's Observational Research Trial (COHORT) study, the CAG repeat length is known for the proband participants. However, whether a family member shares the huntingtin gene status (CAG expanded or not) with the proband is unknown. In this work, we use the expectation-maximization (EM) algorithm to handle the missing huntingtin gene information in first-degree family members in COHORT, assuming that a family member has the same CAG length as the proband if the family member carries a huntingtin gene mutation. We perform simulation studies to examine performance of the proposed method and apply the methods to analyze COHORT proband and family combined data. Our analyses reveal that the estimated cumulative risk of HD symptom onset obtained from the combined data is slightly lower than the risk estimated from the proband data alone.

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Differential Diagnosis of Chorea—HIV Infection Delays Diagnosis of Huntington’s Disease by Years

Brain Sciences ◽

10.3390/brainsci11060710 ◽

2021 ◽

Vol 11 (6) ◽

pp. 710

Author(s):

Jannis Achenbach ◽

Simon Faissner ◽

Carsten Saft

Keyword(s):

Hiv Infection ◽

Huntington's Disease ◽

Huntington’S Disease ◽

Disease Onset ◽

Diagnostic Delay ◽

Depression Scale ◽

Cag Repeat ◽

Psychiatric Disease ◽

Disease Manifestation ◽

Cross Sectional

Background: There is a broad range of potential differential diagnoses for chorea. Besides rare, inherited neurodegenerative diseases such as Huntington’s disease (HD) chorea can accompany basal ganglia disorders due to vasculitis or infections, e.g., with the human immunodeficiency virus (HIV). The clinical picture is complicated by the rare occurrence of HIV infection and HD. Methods: First, we present a case suffering simultaneously from HIV and HD (HIV/HD) focusing on clinical manifestation and disease onset. We investigated cross-sectional data regarding molecular genetic, motoric, cognitive, functional, and psychiatric disease manifestation of HIV/HD in comparison to motor-manifest HD patients without HIV infection (nonHIV/HD) in the largest cohort of HD patients worldwide using the registry study ENROLL-HD. Data were analyzed using ANCOVA analyses controlling for covariates of age and CAG repeat length between groups in IBM SPSS Statistics V.25. Results: The HD diagnosis in our case report was delayed by approximately nine years due to the false assumption that the HIV infection might have been the cause of chorea. Out of n = 21,116 participants in ENROLL-HD, we identified n = 10,125 motor-manifest HD patients. n = 23 male participants were classified as suffering from HIV infection as a comorbidity, compared to n = 4898 male non-HIV/HD patients. Except for age, with HIV/HD being significantly younger (p < 0.050), we observed no group differences regarding sociodemographic, genetic, educational, motoric, functional, and cognitive parameters. Male HIV/HD patients reported about a 5.3-year-earlier onset of HD symptoms noticed by themselves compared to non-HIV/HD (p < 0.050). Moreover, patients in the HIV/HD group had a longer diagnostic delay of 1.8 years between onset of symptoms and HD diagnosis and a longer time regarding assessment of first symptoms by the rater and judgement of the patient (all p < 0.050). Unexpectedly, HIV/HD patients showed less irritability in the Hospital Anxiety and Depression Scale (all p < 0.05). Conclusions: The HD diagnosis in HIV-infected male patients is secured with a diagnostic delay between first symptoms noticed by the patient and final diagnosis. Treating physicians therefore should be sensitized to think of potential alternative diagnoses in HIV-infected patients also afflicted by movement disorders, especially if there is evidence of subcortical atrophy and a history of hyperkinesia, even without a clear HD-family history. Those patients should be transferred for early genetic testing to avoid further unnecessary diagnostics and improve sociomedical care.

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The MID1 Protein: A Promising Therapeutic Target in Huntington’s Disease

Frontiers in Genetics ◽

10.3389/fgene.2021.761714 ◽

2021 ◽

Vol 12 ◽

Author(s):

Annika Heinz ◽

Judith Schilling ◽

Willeke van Roon-Mom ◽

Sybille Krauß

Keyword(s):

Huntington's Disease ◽

Huntington’S Disease ◽

Protein A ◽

Cag Repeat ◽

Cag Repeats ◽

Progressive Movement ◽

Promising Therapeutic Target ◽

Promising Therapeutic Approach ◽

Exon 1 ◽

Polyglutamine Protein

Huntington’s disease (HD) is caused by an expansion mutation of a CAG repeat in exon 1 of the huntingtin (HTT) gene, that encodes an expanded polyglutamine tract in the HTT protein. HD is characterized by progressive psychiatric and cognitive symptoms associated with a progressive movement disorder. HTT is ubiquitously expressed, but the pathological changes caused by the mutation are most prominent in the central nervous system. Since the mutation was discovered, research has mainly focused on the mutant HTT protein. But what if the polyglutamine protein is not the only cause of the neurotoxicity? Recent studies show that the mutant RNA transcript is also involved in cellular dysfunction. Here we discuss the abnormal interaction of the mutant HTT transcript with a protein complex containing the MID1 protein. MID1 aberrantly binds to CAG repeats and this binding increases with CAG repeat length. Since MID1 is a translation regulator, association of the MID1 complex stimulates translation of mutant HTT mRNA, resulting in an overproduction of polyglutamine protein. Thus, blocking the interaction between MID1 and mutant HTT mRNA is a promising therapeutic approach. Additionally, we show that MID1 expression in the brain of both HD patients and HD mice is aberrantly increased. This finding further supports the concept of blocking the interaction between MID1 and mutant HTT mRNA to counteract mutant HTT translation as a valuable therapeutic strategy. In line, recent studies in which either compounds affecting the assembly of the MID1 complex or molecules targeting HTT RNA, show promising results.

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A Patient-Derived Cellular Model for Huntington’s Disease Reveals Phenotypes at Clinically Relevant CAG Lengths

10.1101/291575 ◽

2018 ◽

Author(s):

Claudia Lin-Kar Hung ◽

Tamara Maiuri ◽

Laura Erin Bowie ◽

Ryan Gotesman ◽

Susie Son ◽

...

Keyword(s):

Huntington's Disease ◽

Huntington’S Disease ◽

Cell Lines ◽

Disease Onset ◽

Cag Repeat ◽

Dna Repeats ◽

Cellular Model ◽

Human Telomerase Reverse Transcriptase ◽

Huntingtin Protein ◽

Transformed Cell Lines

ABSTRACTThe huntingtin protein participates in several cellular processes that are disrupted when the polyglutamine tract is expanded beyond a threshold of 37 CAG DNA repeats in Huntington’s disease (HD). Cellular biology approaches to understand these functional disruptions in HD have primarily focused on cell lines with synthetically long CAG length alleles that clinically represent outliers in this disease and a more severe form of HD that lacks age-onset. Patient-derived fibroblasts are limited to a finite number of passages before succumbing to cellular senescence. We used human telomerase reverse transcriptase (hTERT) to immortalize fibroblasts taken from individuals of varying age, sex, disease onset and CAG repeat length, which we have termed TruHD cells. TruHD cells display classic HD phenotypes of altered morphology, size and growth rate, increased sensitivity to oxidative stress, aberrant ADP/ATP ratios and hypophosphorylated huntingtin protein. We additionally observed dysregulated ROS-dependent huntingtin localization to nuclear speckles in HD cells. We report the generation and characterization of a human, clinically relevant cellular model for investigating disease mechanisms in HD at the single cell level, which, unlike transformed cell lines, maintains TP53 function critical for huntingtin transcriptional regulation and genomic integrity.

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Metformin reverses early cortical network dysfunction and behavior changes in Huntington’s disease

eLife ◽

10.7554/elife.38744 ◽

2018 ◽

Vol 7 ◽

Cited By ~ 20

Author(s):

Isabelle Arnoux ◽

Michael Willam ◽

Nadine Griesche ◽

Jennifer Krummeich ◽

Hirofumi Watari ◽

...

Keyword(s):

Huntington's Disease ◽

Huntington’S Disease ◽

Clinical Symptoms ◽

Activity Patterns ◽

Disease Onset ◽

Network Activity ◽

Critical Window ◽

Functional Changes ◽

Window Of Vulnerability

Catching primal functional changes in early, ‘very far from disease onset’ (VFDO) stages of Huntington’s disease is likely to be the key to a successful therapy. Focusing on VFDO stages, we assessed neuronal microcircuits in premanifest Hdh150 knock-in mice. Employing in vivo two-photon Ca2+ imaging, we revealed an early pattern of circuit dysregulation in the visual cortex - one of the first regions affected in premanifest Huntington’s disease - characterized by an increase in activity, an enhanced synchronicity and hyperactive neurons. These findings are accompanied by aberrations in animal behavior. We furthermore show that the antidiabetic drug metformin diminishes aberrant Huntingtin protein load and fully restores both early network activity patterns and behavioral aberrations. This network-centered approach reveals a critical window of vulnerability far before clinical manifestation and establishes metformin as a promising candidate for a chronic therapy starting early in premanifest Huntington’s disease pathogenesis long before the onset of clinical symptoms.

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Parkinsonism with a Hint of Huntington’s from 29 CAG Repeats in HTT

Brain Sciences ◽

10.3390/brainsci9100245 ◽

2019 ◽

Vol 9 (10) ◽

pp. 245

Author(s):

Sipilä JOT

Keyword(s):

Huntington's Disease ◽

Huntington’S Disease ◽

Clinical Phenotype ◽

Cag Repeat ◽

Cag Repeats ◽

Test Results ◽

Intermediate Allele ◽

History Of ◽

Neurophysiological Test ◽

History Of Parkinson’S Disease

Huntington’s disease is caused by at least 36 cytosine-adenine-guanine (CAG) repeats in an HTT gene allele, but repeat tracts in the intermediate range (27–35 repeats) also display a subtle phenotype. This patient had a slightly elongated CAG repeat tract (29 repeats), a prominent family history of Parkinson’s disease (PD), and a clinical phenotype mostly consistent with PD, but early dystonia and poor levodopa response. Neurophysiological test results were more consistent with Huntington’s disease (HD) than PD. It is suggested that the intermediate allele modulated the clinical phenotype of PD in this patient.

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