Variable phenotypic expression and extensive tau pathology in two families with the novel tau mutation L315R.
Mutations in the tau gene cause familial frontotemporal dementia and parkinsonism linked to chromosome 17. Here, we describe two Dutch families with familial frontotemporal dementia associated with the novel missense mutation L315R in exon 11 of tau. The age at onset of disease showed a large variation within each family, ranging from 25 to 64 years. Incomplete penetrance was established in an 82-year-old mutation carrier with no signs of dementia and appeared probable in two additional subjects. The brains of two affected subjects were studied and showed extensive tau pathology in neurons (Pick-like inclusions) and astroglial cells, particularly in the frontotemporal cortex and the hippocampal formation. Sarkosyl-insoluble tau extracted from the cerebral cortex showed the presence of straight and twisted tau filaments and a pattern of pathological tau bands similar to that of Pick's disease. Upon dephosphorylation, only five of the six brain tau isoforms were observed, with the shortest isoform being undetectable. All six tau isoforms were present in soluble brain tau. Recombinant tau proteins with the L315R mutation showed a reduced ability to promote microtubule assembly.
van Herpen
Esther
E
Department of Clinical Genetics, Erasmus Medical Center, Dr. Molewaterplein 40, 3015 GD Rotterdam, the Netherlands.
Rosso
Sonia M
SM
Serverijnen
Lies-Anne
LA
Yoshida
Hirotaka
H
Breedveld
Guido
G
van de Graaf
Raoul
R
Kamphorst
Wouter
W
Ravid
Rivka
R
Willemsen
Rob
R
Dooijes
Dennis
D
Majoor-Krakauer
Daniëlle
D
Kros
Johan M
JM
Crowther
R Anthony
RA
Goedert
Michel
M
Heutink
Peter
P
van Swieten
John C
JC
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000473:pathology* / Q000648:ultrastructure; D001923:Brain Chemistry; D004252:DNA Mutational Analysis; D003704:Dementia / Q000235:genetics*; D005260:Female; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D008870:Microtubules / Q000378:metabolism; D008875:Middle Aged; D020125:Mutation, Missense; D010375:Pedigree; D019683:Penetrance; D010641:Phenotype; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics; D016875:tau Proteins / Q000737:chemistry / Q000235:genetics*
D020033:Protein Isoforms; D016875:tau Proteins