GRN deletion in familial frontotemporal dementia showing association with clinical variability in 3 familial cases

Publication date: May 2017
Source:Neurobiology of Aging, Volume 53
Author(s): Graziella Milan, Sabrina Napoletano, Sabina Pappatà, Maria Teresa Gentile, Luca Colucci-D'Amato, Gennaro Della Rocca, Anna Maciag, Carmen Palermo Rossetti, Laura Fucci, Annibale Puca, Dario Grossi, Alfredo Postiglione, Emilia Vitale
Progranulin (GRN) gene mutations have been genetically associated with frontotemporal dementia (FTD) and are present in about 23% of patients with familial FTD. However, the neurobiology of this secreted glycoprotein remains unclear. Here, we report the identification of 3 pedigrees of Southern Italian extraction in whom FTD segregates with autosomal dominant inheritance patterns. We present evidence that all the available patients in these 3 familial cases are carrying the rare GRN gene exon 6 deletion g10325_10331delCTGCTGT (relative to nt 1 inNG_007886.1), alias Cys157LysfsX97. This mutation was previously described in 2 sporadic cases but was never associated with familial cases. Our patients demonstrate heterogeneous clinical phenotypes, such as the behavioral variant (bvFTD) in the affected men and the nonfluent/agrammatic variant of primary progressive aphasia (nfvPPA) in the affected woman. Haploinsufficiency was revealed by both quantitative real-time PCR of the gene and protein analyses. These findings provide further support for a previously proposed role for the GRN gene in the genetic etiology of FTD and its phenotypic variability.

Graphical abstract

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