Adeno-associated virus in the liver: natural history and consequences in tumour development
GUT
Authors: La Bella, Tiziana; Imbeaud, Sandrine; Peneau, Camille; Mami, Iadh; Datta, Shalini; Bayard, Quentin; Caruso, Stefano; Hirsch, Theo Z.; Calderaro, Julien; Morcrette, Guillaume; Guettier, Catherine; Paradis, Valerie; Amaddeo, Giuliana; Laurent, Alexis; Possenti, Laurent; Chiche, Laurence; Bioulac-Sage, Paulette; Blanc, Jean-Frederic; Letouze, Eric; Nault, Jean-Charles; Zucman-Rossi, Jessica
Abstract
Objective Adeno-associated virus (AAV) is a defective mono-stranded DNA virus, endemic in human population (35%-80%). Recurrent clonal AAV2 insertions are associated with the pathogenesis of rare human hepatocellular carcinoma (HCC) developed on normal liver. This study aimed to characterise the natural history of AAV infection in the liver and its consequence in tumour development. Design Viral DNA was quantified in tumour and non-tumour liver tissues of 1461 patients. Presence of episomal form and viral mRNA expression were analysed using a DNAse/TaqMan-based assay and quantitative RT-PCR. In silico analyses using viral capture data explored viral variants and new clonal insertions. Results AAV DNA was detected in 21% of the patients, including 8% of the tumour tissues, equally distributed in two major viral subtypes: one similar to AAV2, the other hybrid between AAV2 and AAV13 sequences. Episomal viral forms were found in 4% of the non-tumour tissues, frequently associated with viral RNA expression and human herpesvirus type 6, the candidate natural AAV helper virus. In 30 HCC, clonal AAV insertions were recurrently identified in CCNA2, CCNE1, TERT, TNFSF10, KMT2B and GLI1/INHBE. AAV insertion triggered oncogenic overexpression through multiple mechanisms that differ according to the localisation of the integration site. Conclusion We provided an integrated analysis of the wild-type AAV infection in the liver with the identification of viral genotypes, molecular forms, helper virus relationship and viral integrations. Clonal AAV insertions were positive selected during HCC development on non-cirrhotic liver challenging the notion of AAV as a non-pathogenic virus.
Review of the phenotype of early-onset generalised progressive dystonia due to mutations in KMT2B
EUROPEAN JOURNAL OF PAEDIATRIC NEUROLOGY
Authors: Gorman, K. M.; Meyer, E.; Kurian, M. A.
Abstract
In 2016, two research groups independently identified microdeletions and pathogenic variants in the lysine-specific histone methyltransferase 2B gene, KMT2B in patients with early-onset progressive dystonia. KMT2B-dystonia (DYT28) is emerging as an important and frequent cause of childhood-onset progressive generalised dystonia and is estimated to potentially account for up to 10% of early-onset generalised dystonia. Herein, we review variants in KMT2B associated with dystonia, as well as the clinical phenotype, treatment and underlying disease mechanisms. Furthermore, in context of this newly identified condition, we summarise our approach to the genetic investigation of paediatric dystonia. (C) 2017 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.