Dementia due to Huntington’s disease

2020 ◽  
pp. 448-453
Author(s):  
Russell L. Margolis
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Psychiatric Symptoms ◽  
Cag Repeat ◽  
Causative Mutation ◽  
Clinical Onset ◽  
Key Features ◽  
Neurobiological Research ◽  
Clinical Triad ◽  
Near Future

Huntington’s disease (HD), first described in 1872, is perhaps the prototypical hereditary dementia and movement disorder. Key features include autosomal dominant inheritance, typically mid-life clinical onset, and a clinical triad of abnormal voluntary and involuntary movements, subcortical dementia, and psychiatric symptoms. The disease progresses inevitably, with death typically 15–20 years after onset. Neurodegeneration is most prominent in the striatum and cerebral cortex. The discovery of the causative mutation, an expanded CAG repeat in the gene huntingtin, has led to the development of reliable genetic testing for affected and at-risk individuals and an explosion of neurobiological research into HD pathogenesis. While present treatment of HD is limited to managing symptoms, there is considerable optimism that treatments to prevent, slow, or stop disease progression may be feasible in the near future.

scholarly journals The Contribution of Somatic Expansion of the CAG Repeat to Symptomatic Development in Huntington’s Disease: A Historical Perspective

2021 ◽  
Vol 10 (1) ◽  
pp. 7-33
Author(s):  
Darren G. Monckton
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Human Genetics ◽  
Age At Onset ◽  
Cag Repeat ◽  
Model Systems ◽  
Causative Mutation ◽  
Inverse Association ◽  
Independent Manner ◽  
Dna Mismatch

The discovery in the early 1990s of the expansion of unstable simple sequence repeats as the causative mutation for a number of inherited human disorders, including Huntington’s disease (HD), opened up a new era of human genetics and provided explanations for some old problems. In particular, an inverse association between the number of repeats inherited and age at onset, and unprecedented levels of germline instability, biased toward further expansion, provided an explanation for the wide symptomatic variability and anticipation observed in HD and many of these disorders. The repeats were also revealed to be somatically unstable in a process that is expansion-biased, age-dependent and tissue-specific, features that are now increasingly recognised as contributory to the age-dependence, progressive nature and tissue specificity of the symptoms of HD, and at least some related disorders. With much of the data deriving from affected individuals, and model systems, somatic expansions have been revealed to arise in a cell division-independent manner in critical target tissues via a mechanism involving key components of the DNA mismatch repair pathway. These insights have opened new approaches to thinking about how the disease could be treated by suppressing somatic expansion and revealed novel protein targets for intervention. Exciting times lie ahead in turning these insights into novel therapies for HD and related disorders.

scholarly journals Huntington’s Disease in a Patient Misdiagnosed as Conversion Disorder

2018 ◽  
Vol 2018 ◽  
pp. 1-4
Author(s):  
João Machado Nogueira ◽  
Ana Margarida Franco ◽  
Susana Mendes ◽  
Anabela Valadas ◽  
Cristina Semedo ◽  
...  
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Psychiatric Symptoms ◽  
Age Of Onset ◽  
Late Onset ◽  
Psychiatric Patients ◽  
Conversion Disorder ◽  
Cag Repeat ◽  
Clinical Assessments ◽  
Clinical Presentations

Huntington’s disease (HD) is an inherited, progressive, and neurodegenerative neuropsychiatric disorder caused by the expansion of cytosine-adenine-guanine (CAG) trinucleotide in Interested Transcript (IT) 15 gene on chromosome 4. This pathology typically presents in individuals aged between 30 and 50 years and the age of onset is inversely correlated with the length of the CAG repeat expansion. It is characterized by chorea, cognitive deficits, and psychiatric symptoms. Usually the psychiatric disorders precede motor and cognitive impairment, Major Depressive Disorder and anxiety disorders being the most common presentations. We present a clinical case of a 65-year-old woman admitted to our Psychiatric Acute Unit. During the 6 years preceding the admission, the patient had clinical assessments made several times by different specialties that focused only on isolated symptoms, disregarding the syndrome as a whole. In the course of her last admission, the patient was referred to our Neuropsychiatric Team, which made the provisional diagnosis of late-onset Huntington’s disease, later confirmed by genetic testing. This clinical vignette highlights the importance of a multidisciplinary approach to atypical clinical presentations and raises awareness for the relevance of investigating carefully motor symptoms in psychiatric patients.

scholarly journals Molecular mediators, environmental modulators and experience-dependent synaptic dysfunction in Huntington's disease.

2004 ◽  
Vol 51 (2) ◽  
pp. 415-430 ◽  
Author(s):  
Anthony J Hannan
Keyword(s):  
Neurodegenerative Diseases ◽  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Environmental Enrichment ◽  
Molecular Mechanisms ◽  
Psychiatric Symptoms ◽  
Brain Regions ◽  
Cag Repeat ◽  
Autosomal Dominant Disorder ◽  
Gene Environment

Huntington's disease (HD) is an autosomal dominant disorder in which there is progressive neurodegeneration producing motor, cognitive and psychiatric symptoms. HD is caused by a trinucleotide (CAG) repeat mutation, encoding an expanded polyglutamine tract in the huntingtin protein. At least eight other neurodegenerative diseases are caused by CAG/glutamine repeat expansions in different genes. Recent evidence suggests that environmental factors can modify the onset and progression of Huntington's disease and possibly other neurodegenerative disorders. This review outlines possible molecular and cellular mechanisms mediating the polyglutamine-induced toxic 'gain of function' and associated gene-environment interactions in HD. Key aspects of pathogenesis shared with other neurodegenerative diseases may include abnormal protein-protein interactions, selective disruption of gene expression and 'pathological plasticity' of synapses in specific brain regions. Recent discoveries regarding molecular mechanisms of pathogenesis are guiding the development of new therapeutic approaches. Knowledge of gene-environment interactions, for example, could lead to development of 'enviromimetics' which mimic the beneficial effects of specific environmental stimuli. The effects of environmental enrichment on brain and behaviour will also be discussed, together with the general implications for neuroscience research involving animal models.

scholarly journals Psychiatric morbidity and poor follow-up underlie suboptimal functional and survival outcomes in Huntington's disease

2020 ◽  
Author(s):  
Nikhil Ratna ◽  
Nitish L Kamble ◽  
Sowmya D V ◽  
Meera Purushottam ◽  
Pramod K Pal ◽  
...  
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Neurodegenerative Disorder ◽  
Psychiatric Symptoms ◽  
Tertiary Care ◽  
Psychiatric Morbidity ◽  
Cag Repeat ◽  
Duration Of Illness ◽  
Low Middle Income Countries

Abstract BACKGROUND: Huntington’s disease (HD), an inherited, often late-onset, neurodegenerative disorder, is considered to be a rare, orphan disease. Research into its genetic correlates and services for those affected are inadequate in most low-middle income countries, including India. The apparent ‘incurability’ often deters symptomatic and rehabilitative care, resulting in poor quality of life and sub-optimal outcomes. There are no studies assessing disease burden and outcomes from India. METHODS: We attempted to evaluate individuals diagnosed to have HD at our tertiary-care center between 2013 and 2016 for clinical symptoms, functionality, mortality, follow up status through a structured interview, clinical data from medical records and UHDRS-TFC scoring. RESULTS: Of the 144 patients, 25% were untraceable, and another 17 (11.8%) had already died. Mean age at death and duration of illness at the time of death, were 53 years and 7 years respectively, perhaps due to suicides and other comorbidities at an early age. The patients who could be contacted (n=81) were assessed for morbidity and total functional capacity (TFC). Mean CAG repeat length and TFC score were 44.2 and 7.5 respectively. Most individuals (66%) were in TFC stage I and II and could perhaps benefit from several interventions. The TFC score correlated inversely with duration of illness (p<0.0001). The majority were being taken care of at home, irrespective of the physical and mental disability. There was a high prevalence of psychiatric morbidity (91%) including suicidal tendency (22%). Three of the 17 who died had committed suicide, and several other families reported suicidal history in other family members. Only about half the patients (57%) maintained a regular clinical follow-up. CONCLUSIONS: This study demonstrates the poor follow-up rates, significant suicidality and other psychiatric symptoms, sub-optimal survival durations and functional outcomes highlighting the need for holistic care for the majority who appear to be amenable to interventions.

The molecular biology of Huntington's disease

2001 ◽  
Vol 31 (1) ◽  
pp. 3-14 ◽  
Author(s):  
L. W. HO ◽  
J. CARMICHAEL ◽  
J. SWARTZ ◽  
A. WYTTENBACH ◽  
J. RANKIN ◽  
...  
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Cortical Neurons ◽  
Neurodegenerative Disorder ◽  
Psychiatric Symptoms ◽  
Cag Repeat ◽  
Cag Repeats ◽  
Intranuclear Inclusions ◽  
Progressive Dementia ◽  
Cellular Models

Background. Huntington's disease (HD) is a fatal neurodegenerative disorder with an autosomal dominant mode of inheritance. It leads to progressive dementia, psychiatric symptoms and an incapacitating choreiform movement disorder, culminating in premature death. HD is caused by an increased CAG repeat number in a gene coding for a protein with unknown function, called huntingtin. The trinucleotide CAG codes for the amino acid glutamine and the expanded CAG repeats are translated into a series of uninterrupted glutamine residues (a polyglutamine tract).Methods. This review describes the epidemiology, clinical symptomatology, neuropathological features and genetics of HD. The main aim is to examine important findings from animal and cellular models and evaluate how they have enriched our understanding of the pathogenesis of HD and other diseases caused by expanded polyglutamine tracts.Results. Selective death of striatal and cortical neurons occurs. It is likely that the HD mutation confers a deleterious gain of function on the protein. Neuronal intranuclear inclusions containing huntingtin and ubiquitin develop in patients and transgenic mouse models of HD. Other proposed mechanisms contributing to neuropathology include excitotoxicity, oxidative stress, impaired energy metabolism, abnormal protein interactions and apoptosis.Conclusions. Although many interesting findings have accumulated from studies of HD and other polyglutamine diseases, there remain many unresolved issues pertaining to the exact roles of intranuclear inclusions and protein aggregates, the mechanisms of selective neuronal death and delayed onset of illness. Further knowledge in these areas will inspire the development of novel therapeutic strategies.

scholarly journals Endophenotypical drift in Huntington’s disease: a 5-year follow-up study

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Marie N. N. Hellem ◽  
Rebecca K. Hendel ◽  
Tua Vinther-Jensen ◽  
Ida U. Larsen ◽  
Troels T. Nielsen ◽  
...  
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Disease Burden ◽  
Psychiatric Symptoms ◽  
Cag Repeat ◽  
Symptom Trajectories ◽  
Younger Age ◽  
Cardinal Symptoms ◽  
State Examination

Abstract Background Huntington’s disease (HD) is clinically characterized by progressing motor, cognitive and psychiatric symptoms presenting as varying phenotypes within these three major symptom domains. The disease is caused by an expanded CAG repeat tract in the huntingtin gene and the pathomechanism leading to these endophenotypes is assumed to be neurodegenerative. In 2012/2013 we recruited 107 HD gene expansion carriers (HDGECs) and examined the frequency of the three cardinal symptoms and in 2017/2018 we followed up 74 HDGECs from the same cohort to describe the symptom trajectories and individual drift between the endophenotypes as well as potential predictors of progression and remission. Results We found higher age to reduce the probability of improving on psychiatric symptoms; increasing disease burden score ((CAG-35.5) * age) to increase the risk of developing cognitive impairment; increasing disease burden score and shorter education to increase the risk of motor onset while lower disease burden score and higher Mini Mental State Examination increased the probability of remaining asymptomatic. We found 23.5% (N = 8) to improve from their psychiatric symptoms. Conclusions There is no clear pattern in the development of or drift between endophenotypes. In contrast to motor and cognitive symptoms we find that psychiatric symptoms may resolve and thereby not entirely be caused by neurodegeneration. The probability of improving from psychiatric symptoms is higher in younger age and advocates for a potential importance of early treatment.

scholarly journals Psychiatric morbidity and poor follow-up underlie suboptimal functional and survival outcomes in Huntington's disease

2019 ◽  
Author(s):  
Nikhil Ratna ◽  
Nitish L Kamble ◽  
Sowmya D V ◽  
Meera Purushottam ◽  
Pramod K Pal ◽  
...  
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Neurodegenerative Disorder ◽  
Psychiatric Symptoms ◽  
Tertiary Care ◽  
Psychiatric Morbidity ◽  
Cag Repeat ◽  
Duration Of Illness ◽  
Low Middle Income Countries

Abstract BACKGROUND: Huntington’s disease (HD), an inherited, often late-onset, neurodegenerative disorder, is considered to be a rare, orphan disease. Research into its genetic correlates and services for those affected are inadequate in most low-middle income countries, including India. The apparent ‘incurability’ often deters symptomatic and rehabilitative care, resulting in poor quality of life and sub-optimal outcomes. There are no studies assessing disease burden and outcomes from India. METHODS: We attempted to evaluate individuals diagnosed to have HD at our tertiary-care center between 2013 and 2016 for clinical symptoms, functionality, mortality, follow up status through a structured interview, clinical data from medical records & UHDRS TFC scoring. RESULTS: Of the 144 patients, 25% were untraceable, and another 17 (11.8%) had already died. Mean age at and duration of illness at the time of death, were 53 years and 7 years respectively, which is much shorter than in Europe and USA. The patients who could be contacted (n=81) were assessed for symptomatic morbidity and total functional capacity (TFC). Mean CAG repeat length and TFC score were 44.2 and 7.5 respectively. Most individuals (66%) were in TFC stage I and II and could perhaps benefit from several interventions. The TFC score correlated inversely with duration of illness (p<0.0001). The vast majority were being taken care of at home, irrespective of the physical and mental disability. There was a high prevalence of psychiatric morbidity (91%) including suicidal tendency (22%). Three of the 17 who died had committed suicide, and many other families reported suicidal history in other family members. Only about half the patients (57%) maintained a regular clinical follow-up. CONCLUSIONS: This study demonstrates the poor follow-up rates, significant suicidality & other psychiatric symptoms, suboptimal survival durations and functional outcomes highlighting the need for holistic care for the majority who appear to be amenable for interventions.

scholarly journals Brain urea increase is an early Huntington’s disease pathogenic event observed in a prodromal transgenic sheep model and HD cases

2017 ◽  
Vol 114 (52) ◽  
pp. E11293-E11302 ◽  
Author(s):  
Renee R. Handley ◽  
Suzanne J. Reid ◽  
Rudiger Brauning ◽  
Paul Maclean ◽  
Emily R. Mears ◽  
...  
Keyword(s):  
Human Brain ◽  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Neurodegenerative Disorder ◽  
Cag Repeat ◽  
Causative Mutation ◽  
Striatal Neurons ◽  
Psychological Disturbance ◽  
Postmortem Human Brain ◽  
Sheep Model

The neurodegenerative disorder Huntington’s disease (HD) is typically characterized by extensive loss of striatal neurons and the midlife onset of debilitating and progressive chorea, dementia, and psychological disturbance. HD is caused by a CAG repeat expansion in the Huntingtin (HTT) gene, translating to an elongated glutamine tract in the huntingtin protein. The pathogenic mechanism resulting in cell dysfunction and death beyond the causative mutation is not well defined. To further delineate the early molecular events in HD, we performed RNA-sequencing (RNA-seq) on striatal tissue from a cohort of 5-y-old OVT73-line sheep expressing a human CAG-expansion HTT cDNA transgene. Our HD OVT73 sheep are a prodromal model and exhibit minimal pathology and no detectable neuronal loss. We identified significantly increased levels of the urea transporter SLC14A1 in the OVT73 striatum, along with other important osmotic regulators. Further investigation revealed elevated levels of the metabolite urea in the OVT73 striatum and cerebellum, consistent with our recently published observation of increased urea in postmortem human brain from HD cases. Extending that finding, we demonstrate that postmortem human brain urea levels are elevated in a larger cohort of HD cases, including those with low-level neuropathology (Vonsattel grade 0/1). This elevation indicates increased protein catabolism, possibly as an alternate energy source given the generalized metabolic defect in HD. Increased urea and ammonia levels due to dysregulation of the urea cycle are known to cause neurologic impairment. Taken together, our findings indicate that aberrant urea metabolism could be the primary biochemical disruption initiating neuropathogenesis in HD.

scholarly journals Psychiatric morbidity and poor follow-up underlie suboptimal functional and survival outcomes in Huntington's disease

2019 ◽  
Author(s):  
Nikhil Ratna ◽  
Nitish L Kamble ◽  
Sowmya D V ◽  
Meera Purushottam ◽  
Pramod K Pal ◽  
...  
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Neurodegenerative Disorder ◽  
Psychiatric Symptoms ◽  
Tertiary Care ◽  
Psychiatric Morbidity ◽  
Cag Repeat ◽  
Duration Of Illness ◽  
Low Middle Income Countries

Abstract BACKGROUND: Huntington’s disease (HD), an inherited, often late-onset, neurodegenerative disorder, is considered to be a rare, orphan disease. Research into its genetic correlates and services for those affected are inadequate in most low-middle income countries, including India. The apparent ‘incurability’ often deters symptomatic and rehabilitative care, resulting in poor quality of life and sub-optimal outcomes. There are no studies assessing disease burden and outcomes from India. METHODS: We attempted to evaluate individuals diagnosed to have HD at our tertiary-care center between 2013 and 2016 for clinical symptoms, functionality, mortality, follow up status through a structured interview, clinical data from medical records & UHDRS TFC scoring. RESULTS: Of the 144 patients, 25% were untraceable, and another 17 (11.8%) had already died. Mean age at death and duration of illness at the time of death, were 53 years and 7 years respectively, perhaps due to suicides and other comorbidities at an early agewhich is much shorter than in Europe and USA. The patients who could be contacted (n=81) were assessed for morbid symptoms and total functional capacity (TFC). Mean CAG repeat length and TFC score were 44.2 and 7.5 respectively. Most individuals (66%) were in TFC stage I and II and could perhaps benefit from several interventions. The TFC score correlated inversely with duration of illness (p<0.0001). The vast majority were being taken care of at home, irrespective of the physical and mental disability. There was a high prevalence of psychiatric morbidity (91%) including suicidal tendency (22%). Three of the 17 who died had committed suicide, and many other families reported suicidal history in other family members. Only about half the patients (57%) maintained a regular clinical follow-up. CONCLUSIONS: This study demonstrates the poor follow-up rates, significant suicidality & other psychiatric symptoms, suboptimal survival durations and functional outcomes highlighting the need for holistic care for the majority who appear to be amenable for interventions.

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