Alzheimer’s Disease and Frontotemporal Dementia: The Current State of Genetics and Genetic Testing Since the Advent of Next-Generation Sequencing

摘要

The advent of next generation sequencing has changed genetic diagnostics allowing clinicians to test concurrently for phenotypically overlapping conditions such as Alzheimer’s disease and frontotemporal dementia. However, to interpret genetic results, clinicians require an understanding of the benefits and limitations of different genetic technologies, such as the inability to detect large repeat expansions in such diseases as C9orf72-associated frontotemporal dementia and amyotrophic lateral sclerosis. Other types of mutations such as large deletions or duplications and triple repeat expansions may also go undetected. Additionally, the concurrent testing of multiple genes or the whole exome increases the likelihood of discovering variants of unknown significance. Our goal here is to review the current knowledge about the genetics of Alzheimer’s disease and frontotemporal dementia and to suggest up-to-date guidelines for genetic testing for these dementias. Despite the improvements in diagnosis due to biomarker testing, Alzheimer’s disease and frontotemporal dementia can have overlapping symptoms. When used appropriately, genetic testing can elucidate the diagnosis, specific etiology of the disease, provide information for the family, and eligibility for clinical trials. Prior to ordering genetic testing, clinicians must determine the appropriate genes to test, the types of mutations that occur in these genes, and the best type of genetic test to use. Without this analysis, interpretation of genetic results will be difficult. Patients should be counseled about the benefits and limitations of different types of genetic tests, so they can make an informed decision about testing.