title: Phenotypic signatures of genetic frontotemporal dementia.
abstract: OBJECTIVE
  Frontotemporal dementia (FTD) is a clinically, pathologically and genetically heterogeneous disorder. Mutations in a number of genes are associated with FTD, although until recently only two [progranulin (GRN) and microtubule-associated protein tau (MAPT)] were known to be major causes of the disease. This review describes recent progress in identifying clinical and neuroanatomical phenotypes associated with autosomal-dominant FTD.
  
  
  RESULTS
  Around a third to a half of FTD patients have an autosomal dominant pattern of inheritance. Up to 10% of patients have a mutation in GRN and a similar proportion have a mutation in MAPT. Recently a group of patients have been shown to have a hexanucleotide repeat expansion in the noncoding region of chromosome 9 open reading frame 72 (C9ORF72). A further group of patients have an autosomal dominant family history but no mutations in any of the known genes including a group of patients who have the same pathology as GRN mutations (type A TDP-43 pathology) but are negative for GRN mutations. Clinical phenotypes vary across the different mutations. Neuroimaging studies show that GRN and MAPT mutations have distinct patterns of atrophy--asymmetric fronto-temporo-parietal atrophy with GRN versus relatively symmetric medial temporal and orbitofrontal lobe atrophy with MAPT mutations. Neuroimaging of patients with an expansion in C9ORF72 has yet to be studied in detail.
  
  
  CONCLUSIONS
  Genetic FTD is heterogeneous but certain phenotypic signatures of the major causative genes can be identified.
authors: Department of Neurodegenerative Disease, Dementia Research Centre, UCL Institute of Neurology, University College London, Queen Square, London, UK. rohrer@dementia.ion.ucl.ac.uk
authors: Jonathan D
authors: JD
authors: Rohrer
authors: Jason D
authors: JD
authors: Warren
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics; D018797:Cell Cycle Proteins / Q000235:genetics; D025063:Chromosome Disorders / Q000235:genetics; D002899:Chromosomes, Human, Pair 9; D042622:DNA Repeat Expansion; D004268:DNA-Binding Proteins / Q000235:genetics; D000072159:Dynactin Complex; D056827:Endosomal Sorting Complexes Required for Transport / Q000235:genetics; D057180:Frontotemporal Dementia / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics; D008279:Magnetic Resonance Imaging; D008869:Microtubule-Associated Proteins / Q000235:genetics; D009154:Mutation; D010641:Phenotype; D000077153:Progranulins; D034702:RNA-Binding Protein FUS / Q000235:genetics; D000074405:Valosin Containing Protein; D016875:tau Proteins / Q000235:genetics
chemical_list: C503812:CHMP2B protein, human; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D000072159:Dynactin Complex; D056827:Endosomal Sorting Complexes Required for Transport; C492314:GRN protein, human; D036341:Intercellular Signaling Peptides and Proteins; D008869:Microtubule-Associated Proteins; D000077153:Progranulins; D034702:RNA-Binding Protein FUS; D016875:tau Proteins; D000251:Adenosine Triphosphatases; D000074405:Valosin Containing Protein