Suicide attempt in a dopamine agonist withdrawal syndrome in Parkinson's disease.

Dopamine agonist withdrawal syndrome (DAWS) results from the reduction or suspension of dopamine agonist medications; it encompasses mainly psychiatric symptoms, including suicidal behaviors. In patients with Parkinson's disease (PD), the impact of DAWS can be significant in terms of distress and disability; however, we must take this syndrome into account as a threatening condition because suicidal behaviors could be developing in the context of DAWS. Here we present a brief case of DAWS affecting a young man with PD, whom abruptly discontinued DA treatment and developed psychiatric symptoms within two weeks which led to a suicidal attempt.

Worldwide barriers to genetic testing for movement disorders.

BACKGROUND AND PURPOSE: Despite enormous advances in identifying genetic variants responsible for many neurological diseases, access to genetic testing may be limited in clinical practice. The objective of this study was to assess worldwide access to genetic tests for movement disorders and factors impacting their utilization. METHODS: The Rare Movement Disorders Study Group of the International Parkinson and Movement Disorder Society designed an online survey electronically mailed to all 7815 members. RESULTS: Survey data completed by 1269 participants from 109 countries were analysed. Limited access to geneticists and genetic counsellors was reported in many world regions compared to Europe and North America. Availability of genetic testing was limited, with rates of access lower than 50%. Genetic testing for chorea was the most commonly available. For parkinsonism, dystonia, ataxia, hereditary spastic paraplegias and metabolic disorders, there was limited access to genetic testing in all countries compared to Europe and North America, with significant differences found for Africa, Central/South America, Asia. In many regions, genetic testing was supported by either private or public funding. Genetic testing was free of charge in Europe according to 63.5% of respondents. In North America, Africa, Central/South America, Asia and the Middle East access to free of charge genetic testing was by far significantly lower compared to Europe. CONCLUSIONS: This survey highlights difficulties in accessing genetic testing and individuals with expertise in genetics at the worldwide level. In addition, major disparities in genetic testing amongst world regions are highlighted, probably due to a variety of factors including financial barriers.

A novel mutation in PSEN1 (p.Arg41Ser) in an Argentinian woman with early onset Parkinsonism.

INTRODUCTION: Mutations in presenilin-1 (PSEN1) account for the majority of cases of familial autosomal dominant early-onset Alzheimer's disease (AD) as well as in sporadic forms. Atypical presentations are reported including extrapyramidal signs. In the last years, a pleiotropic effect of some PSEN1 variants has been reported in Parkinson's disease (PD). OBJECTIVE: to report a new PSEN1 mutation characterized by early-onset Parkinsonism (EOPD) without dementia or classical AD biomarkers phenotype. PATIENT AND METHODS: An Argentinian 46 years old woman was diagnosed with EOPD at 35 years old with no family history of neurodegenerative disorders. Her medical history included iron deficiency and anemia since childhood. A brain MRI showed moderate frontal atrophy. 18FDG-PET and PiB-PET as well as CSF biomarkers were inconclusive for AD. Two neuropsychological examinations were compatible with a mild non amnestic cognitive impairment. Whole blood DNA was extracted and whole exome sequencing and analysis was performed. RESULTS AND CONCLUSION: A heterozygous novel missense PSEN1 mutation (position 14:73637540, A > T, pArg41Ser) was identified as a likely causative mutation in this patient. To the best of our knowledge, this case is the first PSEN1 mutation with a l-dopa responsive Parkinsonism lacking distinctive classical AD biomarkers. This case opens a new window to explore the pathophysiological link among PSEN1 and EOPDs and contributes to increase the phenotypes of PSEN1 variants.

Neurodegenerative diseases and cancer: sharing common mechanisms in complex interactions.

Several epidemiological studies support low cancer rates in patients with neurodegenerative disorders, including Parkinson's disease, Huntington's disease, and Alzheimer's disease. Different mechanisms were raised as possible causes, from mutated tumor suppressor genes (PARKIN, PINK1) to small interfering RNA based on the CAG trinucleotide repeat expansions located in introns or untranslated regions. However, as every rule has an exception, some tumors have an increased incidence in these neurodegenerative diseases such as breast and skin cancer (melanoma). This mini-review aims to establish the epidemiology between these neurodegenerative disorders and cancer to determine the possible mechanisms involved and therefore set eventual therapeutic applications. According to our findings, we conclude the presence of an inverse relationship among most cancers and the aforementioned neurodegenerative disorders. However, this concept needs to be considered cautiously considering specific genetic and extra-genetic linkage factors for particular tumors.

Huntington disease: Advances in the understanding of its mechanisms.

Huntington disease (HD) is a devastating monogenic autosomal dominant disorder. HD is caused by a CAG expansion in exon 1 of the gene coding for huntingtin, placed in the short arm of chromosome 4. Despite its well-defined genetic origin, the molecular and cellular mechanisms underlying the disease are unclear and complex. Here, we review some of the currently known functions of the wild-type huntingtin protein and discuss the deleterious effects that arise from the expansion of the CAG repeats, which are translated into an abnormally long polyglutamine tract. Also, we present a modern view on the molecular biology of HD as a representative of the group of polyglutamine diseases, with an emphasis on conformational changes of mutant huntingtin, disturbances in its cellular processing, and proteolytic stress in degenerating neurons. The main pathogenetic mechanisms of neurodegeneration in HD are discussed in detail, such as autophagy, impaired mitochondrial biogenesis, lysosomal dysfunction, organelle and protein transport, inflammation, oxidative stress, and transcription factor modulation. However, other unraveling mechanisms are still unknown. This practical and brief review summarizes some of the currently known functions of the wild-type huntingtin protein and the recent findings related to the mechanisms involved in HD pathogenesis.

Late Onset Huntington Disease: Phenotypic and Genotypic Characteristics of 10 Cases in Argentina.

BACKGROUND: Huntington's disease (HD) is a neurodegenerative disorder that includes motor, psychiatric and cognitive manifestations with typical onset of symptoms is in the forties. A percentage of patients (4.4% - 11.5%) may be exceptions to this and manifest symptoms later (>60 years old). Diagnosis of Late onset HD (LoHD) can be a challenge, due to the low suspicion of the disease at this age. OBJECTIVE: To review the genotype and phenotype of LoHD in an Argentinian cohort. METHODS: We reviewed the medical records and genetic testing of a total of 95 individuals with clinical and molecular diagnosis of Huntington's disease, based on 2 institution's registry. RESULTS: Among our HD cohort, 10 patients (10.52%) had LoHD, with variable results regarding family history. The average of repetitions of the expanded allele was 40 (range 38-44). All cases had mild motor symptoms at onset. CONCLUSIONS: Late onset HD can be a diagnostic challenge, due to its slow progression, unawareness of manifestations among patients and in many cases, mild symptomatology that does not warrant medical attention.

Parkinsonisms and Glucocerebrosidase Deficiency: A Comprehensive Review for Molecular and Cellular Mechanism of Glucocerebrosidase Deficiency.

In the last years, lysosomal storage diseases appear as a bridge of knowledge between rare genetic inborn metabolic disorders and neurodegenerative diseases such as Parkinson's disease (PD) or frontotemporal dementia. Epidemiological studies helped promote research in the field that continues to improve our understanding of the link between mutations in the glucocerebrosidase (GBA) gene and PD. We conducted a review of this link, highlighting the association in GBA mutation carriers and in Gaucher disease type 1 patients (GD type 1). A comprehensive review of the literature from January 2008 to December 2018 was undertaken. Relevance findings include: (1) There is a bidirectional interaction between GBA and α- synuclein in protein homeostasis regulatory pathways involving the clearance of aggregated proteins. (2) The link between GBA deficiency and PD appears not to be restricted to α⁻synuclein aggregates but also involves Parkin and PINK1 mutations. (3) Other factors help explain this association, including early and later endosomes and the lysosomal-associated membrane protein 2A (LAMP-2A) involved in the chaperone-mediated autophagy (CMA). (4) The best knowledge allows researchers to explore new therapeutic pathways alongside substrate reduction or enzyme replacement therapies.

Biological and clinical manifestations of juvenile Huntington's disease: a retrospective analysis.

BACKGROUND: Huntington's disease is a rare, neurodegenerative disease caused by an expanded CAG repeat mutation in the huntingtin gene. Compared with adult-onset Huntington's disease, juvenile Huntington's disease (onset ≤20 years) is even rarer and has not been studied extensively. We aimed to further characterise juvenile Huntington's disease by examining the effect of CAG repeat size on disease presentation, progression, and survival. METHODS: We did a retrospective analysis of patients with juvenile Huntington's disease aged 20 years or younger, according to the length of their CAG repeat and who had disabling psychiatric symptoms (with motor symptoms) or motor symptoms alone, and of patients with adult-onset Huntington's disease manifesting aged 30-60 years with 40 or more CAG repeats, from the REGISTRY and ENROLL-HD platforms and from two institutional databases (Lega Italiana Ricerca Huntington Foundation and the Instituto Neurociencias de Buenos Aires and the Sanatorio de la Trinidad Mitre). Patients with psychiatric but no motor symptoms were excluded. We compared symptoms at onset and longitudinally in patients with juvenile Huntington's disease with highly expanded (HE subgroup) or low expansion (LE subgroup) mutations, grouped by hierarchical clustering analysis. We also compared disease progression (longitudinal change in Unified Huntington's Disease Rating Scale-Total Motor Score) and survival of patients with juvenile and adult-onset Huntington's disease. FINDINGS: We extracted medical records from 580 patients entered into the studies or databases between June 23, 2004, and March 31, 2018, of whom 36 patients met our definition of juvenile Huntington's disease and 197 for adult-onset Huntington's disease. According to caregiver reports, gait disturbance was more often a first presenting symptom in the HE subgroup (eight [80%] of 10 patients) than in the LE subgroup (seven [27%] of 26 patients; p=0·0071), whereas loss of hand dexterity was more common in the LE subgroup (11 [42%] of 26 patients) than in the HE subgroup (0 [0%] of 10 patients; p=0·0160). Compared with the LE subgroup, development delay (0 [0%] in the LE subgroup vs nine [90%] in the HE subgroup; p<0·0001), severe gait impairment (nine [35%] in the LE subgroup vs nine [90%] in the HE subgroup; p=0·0072), and seizures (three [11%] in the LE subgroup vs eight [80%] in the HE subgroup; p<0·0001) prevailed over time in the HE subgroup. Disease progression was more rapid in juvenile Huntington's disease (n=14) than in adult-onset Huntington's disease (n=52; generalised estimating equation model, p=0·0003). Of 121 deceased patients, median survival was shorter in the juvenile Huntington's disease (n=17) cohort than in adult-onset Huntington's disease (n=104) cohort (hazard ratio 2·18 [95% CI 1·08-4·40]; p=0·002). INTERPRETATION: Patients with HE juvenile Huntington's disease differ clinically from patients with LE juvenile Huntington's disease or adult-onset Huntington's disease, suggesting reclassification of this particularly aggressive form of Huntington's disease might be required. FUNDING: Lega Italiana Ricerca Huntington Foundation and IRCCS Ospedale Casa Sollievo della Sofferenza.

Holmes Tremor Partially Responsive to Topiramate: A Case Report.

Background: Holmes tremor is a rare symptomatic movement disorder, characterized by a combination of resting, postural, and intention tremor. It is usually caused by lesions in the brainstem, thalamus, and cerebellum. Despite pharmacological advances, its treatment remains a challenge; many medications have been used with various degrees of effectiveness. Stereotactic thalamotomy and deep brain stimulation in the ventralis intermedius nucleus have been effective surgical procedures in cases refractory to medical treatment. Case Report: Here we report a young woman with topiramate-responsive Holmes tremor secondary to a brainstem cavernoma. Discussion: Herein we report a Holmes tremor responsive to Topiramate.

A Treatable Rare Cause of Progressive Ataxia and Palatal Tremor.

Background: Cerebrotendinous xanthomatosis is a rare autosomal recessive neurometabolic disorder characterized by chronic diarrhea, tendon xanthomas, juvenile cataracts, and neurological symptoms. Case Report: An adult patient with cerebrotendinous xanthomatosis exhibited ataxia and palatal tremor in the absence of tendon xanthomas and cataracts. Discussion: The importance of this case resides on the fact that cerebrotendinous xanthomatosis should be considered as a possible etiology of the syndrome of progressive ataxia with palatal tremor, even in the absence of tendon xanthomas and cataracts. Early diagnosis is critical to the institution of specific treatment with chenodeoxycholic acid.

Optical coherence tomography (OCT) study in Argentinean Huntington's disease patients.

BACKGROUND: Huntington's disease (HD) is a genetic, rare and progressive neurodegenerative disorder that causes motor and cognitive impairment in midlife patients. Although retinal damage was observed in animal HD models and in patients with other neurodegenerative diseases, we still need confirmation of impairment in HD patients. Optical coherence tomography (OCT) is a non-invasive methodology that analyses the retinal nerve fibre layers (RNFL) and could reflect processes of neurodegeneration. METHODS: A cross-sectional study with 14 HD patients who underwent a spectral domain OCT. Results were compared with a control group. Demographic data were also obtained. RESULTS: Temporal and superior RNFL sectors in HD showed a significant RNFL thinning compared with a control group. However, no differences were identified in mean total RNFL thickness between HD patients and controls. CONCLUSIONS: OCT is a rapid and non-invasive technique that can be investigated in larger cohorts of patients to assess its potential role as a biomarker in HD patients.

Prodromal Clinical Markers of Parkinson disease in Gaucher Disease Individuals.

Heterozygous mutations in the glucocerebrosidase (GBA) gene have been reported as a common risk factor for the development of Parkinson's disease (PD) in Gaucher disease (GD) patients and in heterozygous GBA mutation positive carriers. In this study, we analyzed the occurrence of prodromal markers of PD in an Argentinean cohort with type 1 GD. After signed informed consent, we evaluated 26 patients with type 1 GD under enzymatic replacement therapy from a cohort of the Hospital Ricardo Gutierrez GD Study Group in Buenos Aires City, Argentina. We performed an extensive neurological examination, including cognitive assessment by Montreal Cognitive Assessment (MoCA) and a questionnaire performed ad hoc, to identify non-motor PD symptoms. Parasomnias were reported by 7 patients (26.92%), rapid eye movement behavior disorders in 2 (7.69%), constipation in 2 (7.69%), hyposmia in 1 (3.84%), tremor in 1 (3.84%), and depression in 3 cases (11.53%). MoCA assessment was abnormal in 44.44% of patients. No patient fulfilled PD diagnostic criteria (Queen Square Brain Bank criteria). The identification of prodromal markers of PD in type 1 GD suggests that this population represents a very interesting cohort for identifying potential biomarkers and neuroprotective therapies for PD.