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This Article Full Text Full Text (PDF) CME: Take the course for this article: Volume 73, Number 18, November 3, 2009 Correspondence: Submit a response Alert me when this article is cited Alert me when Correspondence are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Rohrer, J. D. Articles by Rossor, M. N. PubMed PubMed Citation Articles by Rohrer, J. D. Articles by Rossor, M. N. Related Collections Frontotemporal dementia All Genetics

The heritability and genetics of frontotemporal lobar degeneration

From the Dementia Research Centre (J.D.R., N.C.F., J.D.W., M.N.R.) and MRC Prion Unit (J.U., D.R., J.B., A.M.I., A.A., S.M.), Department of Neurodegenerative Disease, Reta Lila Weston Institute (R.F., J.H.), and Queen Square Brain Bank (J.V., R.d.S., J.H., T.R.), Department of Molecular Neuroscience, UCL Institute of Neurology, University College London, Queen Square, London, UK; Texas Tech University (R.F.), Health Sciences Center, Department of Internal Medicine, Lubbock, TX; Laboratory of Neurogenetics (R.G.), National Institute of Aging, National Institutes of Health, Bethesda, MD; Center for Neuroscience and Cell Biology (R.G.), University of Coimbra, Coimbra, Portugal; and Department of Pathology and Laboratory Medicine (I.R.A.M.), Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada.

Address correspondence and reprint requests to Professor Martin N. Rossor, Dementia Research Centre, Institute of Neurology, Queen Square, London WC1N 3BG, UK mrossor{at}dementia.ion.ucl.ac.uk

Background: Frontotemporal lobar degeneration (FTLD) is a genetically and pathologically heterogeneous neurodegenerative disorder.

Methods: We collected blood samples from a cohort of 225 patients with a diagnosis within the FTLD spectrum and examined the heritability of FTLD by giving each patient a family history score, from 1 (a clear autosomal dominant history of FTLD) through to 4 (no family history of dementia). We also looked for mutations in each of the 5 disease-causing genes (MAPT, GRN, VCP, CHMP2B, and TARDP) and the FUS gene, known to cause motor neuron disease.

Results: A total of 41.8% of patients had some family history (score of 1, 2, 3, or 3.5), although only 10.2% had a clear autosomal dominant history (score of 1). Heritability varied across the different clinical subtypes of FTLD with the behavioral variant being the most heritable and frontotemporal dementia–motor neuron disease and the language syndromes (particularly semantic dementia) the least heritable. Mutations were found in MAPT (8.9% of the cohort) and GRN (8.4%) but not in any of the other genes. Of the remaining patients without mutations but with a strong family history, 7 had pathologic confirmation, falling into 2 groups: type 3 FTLD-TDP without GRN mutations (6) and FTLD-UPS (1).

Conclusion: These findings show that frontotemporal lobar degeneration (FTLD) is a highly heritable disorder but heritability varies between the different syndromes. Furthermore, while MAPT and GRN mutations account for a substantial proportion of familial cases, there are other genes yet to be discovered, particularly in patients with type 3 FTLD-TDP without a GRN mutation.

Abbreviations: bvFTD = behavioral variant frontotemporal dementia; CBS = corticobasal syndrome; FTLD = frontotemporal lobar degeneration; LPA = logopenic/phonologic variant of primary progressive aphasia; MND = motor neuron disease; PNFA = progressive nonfluent aphasia; PPA = primary progressive aphasia; PSP = progressive supranuclear palsy; SemD = semantic dementia.

Disclosure: Author disclosures are provided at the end of the article.

Received May 1, 2009. Accepted in final form August 3, 2009.