Silencing Huntington's chorea: Is RNA Interference a Potential Cure?

Journal of Huntington's disease, 2020

Background: Anosognosia, or unawareness of illness of deficits, has been observed in Huntington's disease (HD) in relation to motor and cognitive signs and symptoms. Most studies of awareness in HD have used self-report questionnaire methodology rather than asking patients to report on their symptoms in real-time. The two studies in which patients were asked about their chorea in real-time had small sample sizes and only examined patients early in disease progression. Objective: To examine awareness of chorea in real-time in HD patients across a broad range of disease progression. Methods: Fifty HD patients across motor and cognitive impairment severity were asked if they noticed any involuntary movements after completing a simple working memory task used to elicit chorea. A movement disorders specialist rated the presence or absence of chorea while the patients completed the task. Disagreement between the patient and movement disorders specialist's ratings was considered to be an indicator of unawareness. Results: Approximately 46% of patients who exhibited chorea did not report chorea. Eighty-eight percent of participants who acknowledged chorea did not report chorea in all parts of the body that chorea was observed. Conclusions: HD patients demonstrate unawareness of chorea across cognitive and motor sign severity.

2011

Huntington disease (HD) is a rare neurodegenerative disorder of the central nervous system characterized by unwanted choreatic movements, behavioral and psychiatric disturbances and dementia. Prevalence in the Caucasian population is estimated at 1/10,000-1/20,000. Mean age at onset of symptoms is 30-50 years. In some cases symptoms start before the age of 20 years with behavior disturbances and learning difficulties at school (Juvenile Huntington's disease; JHD). The classic sign is chorea that gradually spreads to all muscles. All psychomotor processes become severely retarded. Patients experience psychiatric symptoms and cognitive decline. HD is an autosomal dominant inherited disease caused by an elongated CAG repeat (36 repeats or more) on the short arm of chromosome 4p16.3 in the Huntingtine gene. The longer the CAG repeat, the earlier the onset of disease. In cases of JHD the repeat often exceeds 55. Diagnosis is based on clinical symptoms and signs in an individual with a parent with proven HD, and is confirmed by DNA determination. Pre-manifest diagnosis should only be performed by multidisciplinary teams in healthy at-risk adult individuals who want to know whether they carry the mutation or not. Differential diagnoses include other causes of chorea including general internal disorders or iatrogenic disorders. Phenocopies (clinically diagnosed cases of HD without the genetic mutation) are observed. Prenatal diagnosis is possible by chorionic villus sampling or amniocentesis. Preimplantation diagnosis with in vitro fertilization is offered in several countries. There is no cure. Management should be multidisciplinary and is based on treating symptoms with a view to improving quality of life. Chorea is treated with dopamine receptor blocking or depleting agents. Medication and non-medical care for depression and aggressive behavior may be required. The progression of the disease leads to a complete dependency in daily life, which results in patients requiring fulltime care, and finally death. The most common cause of death is pneumonia, followed by suicide.

The Lancet, 2007

Search strategy and selection criteria I searched Pub Med from 1965-2005 for the term "Huntington's Disease" cross referenced with the terms "apoptosis", "axonal transport", "mitochondria", "animal model", "proteosome", "transcription", "juvenile", "suicide", "neurotransmitters", "age of onset", "identical twins", "neurodegeneration", and "imaging". I translated all non-English language publications that resulted from this search strategy. I mainly selected articles from the past fi ve years, but did not exclude commonly referenced and highly regarded older publications. I also searched the reference lists of articles identifi ed by this search strategy and selected those that I judged relevant. Several review articles and book chapters were included because they provide comprehensive overviews beyond the scope of this Seminar. The reference list was further modifi ed during the peer-review process based on comments from the reviewers. Year Event Publications (n)* 1374 Epidemic dancing mania described .. 1500 Paracelsus suggests CNS origin for chorea .. 1686 Thomas Sydenham describes post-infectious chorea .. 1832 John Elliotson identifi es inherited form of chorea 1 .. 1872 George Huntington characterises Huntington's disease 5 ..

Neurologic Clinics, 2009

2012

Huntington's Disease (HD) is an autosomal dominant, neurodegenerative disease. It is characterized by severe involuntary motor dysfunction, so-called choreic movements, neurological and psychiatric symptoms and cognitive impairments that lead to dementia (Bates et al., 2002). Genetic markers for the gene that causes HD were identified in 1983, located on the short arm of chromosome four (Gusella et al., 1983). Ten years later in 1993 the gene was cloned (Huntington's Disease Collaborative Research Group, 1993).

International Journal of Research in Pharmaceutical Sciences, 2020

Huntington’s disease (HD) is a rare autosomal dominant, fatal neurodegenerative disorder of the central nervous system characterized by unwanted choreaticmovements, behavioural disruption, psychiatric disturbances anddementia. This condition is characterized by progressive degeneration of neurons within the basal ganglia, primarily the caudate and the putamen. As the disease progresses, neuronal losses occur in the white matter, cerebral cortex and thalamus. In this article, the authors reviewed the genetic aspects, etiological factors, stages of the disease condition along with the signs and symptoms, various diagnostic procedures besides with the pharmacological and non-pharmacological management of the Huntington’s disease. This disease is inherited within the families, and the pathophysiology of Huntington disease is restricted to the brain, where degeneration begins initially in the striatum, spreads to the cortex and eventually appears throughout the brain.The pathogenesis of ...

Current neurology and neuroscience reports, 2011

Cognition has been well characterized in the various stages of Huntington disease (HD) as well as in the prodrome before the motor diagnosis is given. Although the clinical diagnosis of HD relies on the manifestation of motor abnormalities, the associated impairments have been growing in prominence for several reasons. First, research to understand the most debilitating aspects of HD has suggested that cognitive and behavioral changes place the greatest burden on families, are most highly associated with functional decline, and can be predictive of institutionalization. Second, cognitive impairments are evident at least 15 years prior to the time at which motor diagnosis is given. Finally, cognitive decline is associated with biological markers such as brain atrophy, circulating levels of brain-derived neurotrophic factors, and insulin-like growth factor 1. Efforts are now underway to develop valid and reliable measures of cognition in the prodrome as well as in all stages of HD so ...

Journal of Neurology, Neurosurgery & Psychiatry, 1977

SUM MARY Fifteen patients affected by Huntington's chorea were divided into two groups, 'slow' and 'fast', according to IQ scores on the Wechsler-Bellevue scale, and scores on some motor performance tests. A possible correlation was looked for between some biochemical data (cerebrospinal fluid (CSF), homovanillic acid (HVA), and 5-hydroxyindolacetic acid (5HIAA) levels, plasma dopamine-beta-hydroxylase (DBH), dopamine (DA) uptake by platelets), and clinical data (duration of illness, severity of symptoms, age of patients, IQ scores, 'slow' and 'fast' groups). The CSF, HVA, and 5HIAA levels were found to be significantly lowered in comparison with normal controls. DBH activity and DA uptake by platelets did not differ significantly from normal subjects. Treatment with haloperidol in all patients and with dipropylacetic acid in three patients did not appear to modify the CSF, HVA, and 5HIAA concentrations, the plasma DBH activity, or the DA uptake. There were no significant differences in the CSF, HVA, and 5HIAA contents between the two groups of patients, and there was no correlation between biochemical data and clinical features.