Overview
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Alzheimer Disease (AD) is the most common cause of dementia and one of the leading causes of morbidity and mortality in the aging population. The main clinical characteristic of AD is dementia that typically begins with subtle and poorly recognized failure of memory also known as mild cognitive impairment, slowly becoming more severe and eventually incapacitating. Other findings include confusion, disorientation, language disturbances, agitation etc. 95% of all AD is late onset, typically over the age of 60-65, however, 5% is early onset. Approximately 25% of all AD is familial and 75% is nonfamilial. Familial forms of AD have a strong genetic predisposition. While the pathogenesis of AD remains unclear, all forms of AD appear to share overproduction and/or decreased clearance of amyloid beta peptides. The modes of inheritance of familial forms of AD are autosomal dominant and recessive patterns.
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The Igenomix Alzheimer Disease Precision Panel can be used as a tool for an accurate diagnosis and differential diagnosis of dementia ultimately leading to a better management and prognosis of the disease. It provides a comprehensive analysis of the genes involved in this disease using next-generation sequencing (NGS) to fully understand the spectrum of relevant genes involved, and their high or intermediate penetrance.
Indication
- The Igenomix Alzheimer Disease Precision Panel is used for patients with a clinical suspicion or diagnosis presenting with or without the following symptoms:
- Memory loss
- Family history of early-onset AD
- Confusion about the location of familiar places
- Taking longer to accomplish normal, daily tasks
- Trouble handling money and paying bills
- Compromised judgment
- Loss of spontaneity
- Mood and personality changes
Clinical Utility
The clinical utility of this panel is:
- The genetic and molecular confirmation for an accurate clinical diagnosis of a symptomatic patient.
- Early initiation of treatment involving a multidisciplinary team in the form of medical care with antiparkinsonian agents, antiepileptic drugs, antidepressants, anxiolytics etc. Mental activities are recommended to potentiate cognitive retraining.
- Risk assessment of asymptomatic family members according to the mode of inheritance via genetic counselling.
- Improvement of delineation of genotype-phenotype correlation given the variability of severity and course of disease.
References
Bird TD. Alzheimer Disease Overview. 1998 Oct 23 [Updated 2018 Dec 20]. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2021. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1161/
Kuller, L., & Lopez, O. (2011). Dementia and Alzheimer’s disease: A new direction. The 2010 Jay L. Foster Memorial Lecture. Alzheimer’s & Dementia, 7(5), 540-550. doi: 10.1016/j.jalz.2011.05.901
Montine, T., Phelps, C., Beach, T., Bigio, E., Cairns, N., & Dickson, D. et al. (2011). National Institute on Aging–Alzheimer’s Association guidelines for the neuropathologic assessment of Alzheimer’s disease: a practical approach. Acta Neuropathologica, 123(1), 1-11. doi: 10.1007/s00401-011-0910-3
Reitz C. (2015). Genetic diagnosis and prognosis of Alzheimer’s disease: challenges and opportunities. Expert review of molecular diagnostics, 15(3), 339–348. https://doi.org/10.1586/14737159.2015.1002469
Goldman, J. S., & Van Deerlin, V. M. (2018). Alzheimer’s Disease and Frontotemporal Dementia: The Current State of Genetics and Genetic Testing Since the Advent of Next-Generation Sequencing. Molecular diagnosis & therapy, 22(5), 505–513. https://doi.org/10.1007/s40291-018-0347-7
Sancesario, G. M., & Bernardini, S. (2018). Alzheimer’s disease in the omics era. Clinical biochemistry, 59, 9–16. https://doi.org/10.1016/j.clinbiochem.2018.06.011