英国、加拿大等国最新研究显示，一种罕见的能够引起早期痴呆的大脑失常，是高度遗传的。这项研究结果发布在11月3日的Neurology上。
这种大脑失常，叫额颞叶型失智症（frontotemporal dementia），就是以前的皮克病（Pick's disease），会引起大脑的部分破坏，导致痴呆，包括语言困难或行为和性格的变化。这种疾病通常发病年龄在65岁以下。
了解你的家庭健康史可能是一种预测该疾病发病风险的方法，研究人员Jonathan Rohrer介绍说。
研究人员采集了225位参与者的血样，进行额颞叶型失智症的分析。这些人还会被问及该病的家族史，并给出得分（1到4分）。1分代表该患者至少有3个亲戚患有该疾病并且是常染色体显性遗传，也就是说受到影响的人有一个变异的基因和一个正常的基因，个体有50%的几率会将变异的基因传递到下一代中，导致后代遭受该疾病影响。4分则代表该患者没有额颞叶型失智症的家族史。
这项研究表明，将近42%的参与者的得分在1-3.5之间，也就是说他们中或多或少有一些额颞叶型失智症的家族史。只有10%有常染色体基因史。此外研究人员进行了5个候选变异基因的DNA检测，发现了2个突变基因。
许多人仍然有着一个强大的额颞叶型失智症家族史，即使没有发现任何已知的基因突变，这表明还存在着导致额颞叶型失智症的未知基因。研究人员表示，新基因及其变异的发现将有助于打开治疗和预防痴呆的大门。（生物谷Bioon.com）
生物谷推荐原始出处：
NEUROLOGY 2009;73:1451-1456
The heritability and genetics of frontotemporal lobar degeneration
J. D. Rohrer, MRCP, R. Guerreiro, MS, J. Vandrovcova, PhD, J. Uphill, BSc, D. Reiman, J. Beck, BSc, A. M. Isaacs, DPhil, A. Authier, MSc, R. Ferrari, BSc, N. C. Fox, MD, FRCP, I.R.A. Mackenzie, PhD, J. D. Warren, PhD, FRACP, R. de Silva, DPhil, J. Holton, PhD, T. Revesz, MD, J. Hardy, PhD, S. Mead, PhD, MRCP and M. N. Rossor, MD, FRCP
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.
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.
