Genetic discoveries of Alzheimer’s disease are the drivers of our understanding, and together with polygenetic risk stratification can contribute towards planning of feasible and efficient preventive and curative clinical trials. We first perform a large genetic association study by merging all available case-control datasets and by-proxy study results (discovery n = 409,435 and validation size n = 58,190). Here, we add six variants associated with Alzheimer’s disease risk (near APP, CHRNE, PRKD3/NDUFAF7, PLCG2 and two exonic variants in the SHARPIN gene). Assessment of the polygenic risk score and stratifying by APOE reveal a 4 to 5.5 years difference in median age at onset of Alzheimer’s disease patients in APOE ɛ4 carriers. Because of this study, the underlying mechanisms of APP can be studied to refine the amyloid cascade and the polygenic risk score provides a tool to select individuals at high risk of Alzheimer’s disease.

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Retinal vasculopathy with cerebral leukodystrophy (RVCL) is an adult-onset disorder caused by C-terminal heterozygous frameshift (fs) mutations in the human 3'-5' DNA exonuclease TREX1. Hereditary systemic angiopathy (HSA) is considered a variant of RVCL with systemic involvement of unknown genetic cause, described in a unique family so far. Here we describe the second case of RVCL with systemic involvement, characterized by cerebral calcifications and pseudotumoral lesions, retinopathy, osteonecrosis, renal and hepatic failure. The genetic screening of TREX1 in this patient revealed the novel heterozygous T270fs mutation on the C-terminal region. On the same gene, we found the V235fs mutation, formerly shown in RVCL, in one patient previously reported with HSA. These mutations lead to important alterations of the C-terminal of the protein, with the loss of the transmembrane helix (T270fs) and the insertion of a premature stop codon, resulting in a truncated protein (V235fs). Functional analysis of T270fs-mutated fibroblasts showed a prevalent localization of the protein in the cytosol, rather than in the perinuclear region. RVCL with systemic involvement is an extremely rare condition, whose diagnosis is complex due to multiorgan manifestations, unusual radiological and histopathological findings, not easily attributable to a single disease. It should be suspected in young adults with systemic microangiopathy involving retina, liver, kidney, bones and brain. Here we confirm the causative role played by TREX1 autosomal dominant fs mutations disrupting the C-terminal of the protein, providing a model for the study of stroke in young adults.

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The presence of Epstein-Barr Virus (EBV) DNA in cerebrospinal fluid (CSF) and peripheral blood (PB) samples collected from 55 patients with clinical and radiologically-active relapsing-remitting MS (RRMS) and 51 subjects with other neurological diseases was determined using standardized commercially available kits for viral nucleic acid extraction and quantitative EBV DNA detection. Both cell-free and cell-associated CSF and PB fractions were analyzed, to distinguish latent from lytic EBV infection. EBV DNA was detected in 5.5% and 18.2% of cell-free and cell-associated CSF fractions of patients with RRMS as compared to 7.8% and 7.8% of controls; plasma and peripheral blood mononuclear cells (PBMC) positivity rates were 7.3% and 47.3% versus 5.8% and 31.4%, respectively. No significant difference in median EBV viral loads of positive samples was found between RRMS and control patients in all tested samples. Absence of statistically significant differences in EBV positivity rates between RRMS and control patients, despite the use of highly sensitive standardized methods, points to the lack of association between EBV and MS disease activity.