| 1. |
- Heinzel, Sebastian, et al.
(författare)
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Clinical relevance and translational impact of reduced penetrance in genetic movement disorders
- 2022
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Ingår i: Medizinische Genetik. - : Walter de Gruyter. - 0936-5931 .- 1863-5490. ; 34:2, s. 151-156
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Tidskriftsartikel (refereegranskat)abstract
- Reduced penetrance is an important but underreported aspect in monogenic diseases. It refers to the phenomenon that carriers of pathogenic variants do not manifest with an overt disease. Clinical expressivity, on the other hand, describes the degree to which certain disease characteristics are present. In this article, we discuss the implications of reduced penetrance on genetic testing and counseling, outline how penetrance can be estimated in rare diseases using large cohorts and review the ethical, legal and social implications of studying non-manifesting carriers of pathogenic mutations. We highlight the interplay between reduced penetrance and the prodromal phase of a neurodegenerative disorder through the example of monogenic Parkinson's disease and discuss the therapeutic implications.
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| 2. |
- Prasuhn, Jannik, et al.
(författare)
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Task matters-challenging the motor system allows distinguishing unaffected Parkin mutation carriers from mutation-free controls
- 2021
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Ingår i: Parkinsonism & Related Disorders. - : Elsevier. - 1353-8020 .- 1873-5126. ; 86, s. 101-104
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Tidskriftsartikel (refereegranskat)abstract
- Background: Heterozygous carriers of Parkin mutations are suggested to be at risk of developing Parkinson's disease, while biallelic variants are associated with typical autosomal recessive early-onset PD. Investigating unaffected heterozygous mutation carriers holds the potential of a deeper understanding of monogenic PD and has implications for PD in general, in particular regarding the prodromal phase.Objectives: To discriminate healthy Parkin mutation carriers from healthy non-mutation carriers using a multimodal approach.Methods: Twenty-seven healthy heterozygous Parkin mutation carriers (13 female. age: 48 +/- 13 years) and 24 healthy non-mutation carriers (14 female. age: 48 +/- 15 years) from the CHRIS study (Cooperative Health Research in South Tyrol) were recalled based on their genetic profile and underwent a blinded assessment of motor and non-motor PD symptoms, transcranial sonography and sensor-based posturography and gait analyses under different conditions with increasing difficulty. For the latter, gradient-boosted trees were used to discriminate between carriers and non-carriers. The classification accuracy and the area under the curve of the receiver-operator characteristics curve were calculated.Results: We observed no differences concerning motor or non-motor symptoms and substantia nigra hyperechogenicity. The best gradient-boosted trees-based model on posturography measurements (tandem feet, eyes closed, firm surface), however, showed a classification accuracy of up to 86%. The best-performing gradientboosted trees-based model for gait analyses showed a balanced accuracy of up to 87% (dual-tasking).Conclusions: Sensor-based quantification of movements allows to discriminate unaffected heterozygous mutation carriers from mutation-free controls. Thereby, it is crucial to challenge the motor system with more difficult tasks to unmask subtle motor alterations.
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| 4. |
- Wittke, Christina, et al.
(författare)
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Genotype–Phenotype Relations for the Atypical Parkinsonism Genes : MDSGene Systematic Review
- 2021
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Ingår i: Movement Disorders. - : Wiley. - 0885-3185 .- 1531-8257. ; 36:7, s. 1499-1510
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Forskningsöversikt (refereegranskat)abstract
- This Movement Disorder Society Genetic mutation database Systematic Review focuses on monogenic atypical parkinsonism with mutations in the ATP13A2, DCTN1, DNAJC6, FBXO7, SYNJ1, and VPS13C genes. We screened 673 citations and extracted genotypic and phenotypic data for 140 patients (73 families) from 77 publications. In an exploratory fashion, we applied an automated classification procedure via an ensemble of bootstrap-aggregated (“bagged”) decision trees to distinguish these 6 forms of monogenic atypical parkinsonism and found a high accuracy of 86.5% (95%CI, 86.3%–86.7%) based on the following 10 clinical variables: age at onset, spasticity and pyramidal signs, hypoventilation, decreased body weight, minimyoclonus, vertical gaze palsy, autonomic symptoms, other nonmotor symptoms, levodopa response quantification, and cognitive decline. Comparing monogenic atypical with monogenic typical parkinsonism using 2063 data sets from Movement Disorder Society Genetic mutation database on patients with SNCA, LRRK2, VPS35, Parkin, PINK1, and DJ-1 mutations, the age at onset was earlier in monogenic atypical parkinsonism (24 vs 40 years; P = 1.2647 × 10−12) and levodopa response less favorable than in patients with monogenic typical presentations (49% vs 93%). In addition, we compared monogenic to nonmonogenic atypical parkinsonism using data from 362 patients with progressive supranuclear gaze palsy, corticobasal degeneration, multiple system atrophy, or frontotemporal lobar degeneration. Although these conditions share many clinical features with the monogenic atypical forms, they can typically be distinguished based on their later median age at onset (64 years; IQR, 57–70 years). In conclusion, age at onset, presence of specific signs, and degree of levodopa response inform differential diagnostic considerations and genetic testing indications in atypical forms of parkinsonism.
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