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Title
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Genetic screening in early-onset dementia patients with unclear phenotype : relevance for clinical diagnosis
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Author
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Abstract
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| In a prospective study of dementia in Flanders (Belgium), we observed a substantial fraction of early-onset dementia patients who did not fulfill the criteria for a specific dementia subtype, leaving the patients without a precise clinical diagnosis. We selected 211 of these patients for genetic testing of causal genes linked to neurodegenerative brain diseases. In this group, the onset or inclusion age was 59.9 ± 8.2 years and 27.4% had a positive family history. We used a panel of 16 major genes linked to Alzheimer's disease, frontotemporal dementia, amyotrophic lateral sclerosis, Parkinson's disease, and prion diseases. In addition, we tested for the presence of a pathogenic C9orf72 repeat expansion. We identified 13 rare variants in 15 patients, including a carrier of variants in 2 different genes. Six patients (2.84%), carried a mutation in a Mendelian causal gene, that is, APP, MAPT, SOD1, TBK1, and C9orf72. In the other 7 patients, 7 variants were of uncertain significance, including a frameshift mutation in PSEN2, p.G359Lfs*74, in 2 patients sharing a common haplotype, and in LRRK2, p.L2063fs*. Expression studies showed reduced PSEN2 and a near complete loss of LRRK2, in lymphoblast cells or brain material of these patients. Overall, our study underscores the relevance of genetic testing of known causal genes in early-onset patients with symptomatology of neurodegenerative dementia but an unclear clinical diagnosis. A positive genetic result can help to obtain a precise diagnosis as well as a better understanding of the presence of multiple affected relatives in the family. |
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Language
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English
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Source (journal)
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Neurobiology of aging. - Fayetteville, N.Y.
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Publication
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Fayetteville, N.Y.
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2018
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ISSN
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0197-4580
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DOI
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10.1016/J.NEUROBIOLAGING.2018.04.015
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Volume/pages
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69
(2018)
, 8 p.
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Article Reference
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292.e7
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ISI
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000439651000031
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Pubmed ID
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29859640
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Medium
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E-only publicatie
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Full text (Publisher's DOI)
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Full text (open access)
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