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BackgroundEarly onset dementias (EOD) are rare neurodegenerative dementias that present before 65 years. Genetic factors have a substantially higher pathogenetic contribution in EOD patients than in late onset dementia.ObjectiveTo identify known and/or novel rare variants in major candidate genes associated to EOD by high-throughput sequencing. Common-risk variants of apolipoprotein E (APOE) and prion protein (PRNP) genes were also assessed.MethodsWe studied 22 EOD patients recruited in Memory Clinics, in the context of studies investigating genetic forms of dementia. Two methodological approaches were applied for the target-Next Generation Sequencing (NGS) analysis of these patients. In addition, we performed progranulin plasma dosage, C9Orf72 hexanucleotide repeat expansion analysis, and APOE genotyping.ResultsWe detected three rare known pathogenic mutations in the GRN and PSEN2 genes and eleven unknown-impact mutations in the GRN, VCP, MAPT, FUS, TREM2, and NOTCH3 genes. Six patients were carriers of only common risk variants (APOE and PRNP), and one did not show any risk mutation/variant. Overall, 69% (n = 9) of our early onset Alzheimer's disease (EAOD) patients, compared with 34% (n = 13) of sporadic late onset Alzheimer's disease (LOAD) patients and 27% (n = 73) of non-affected controls (ADNI, whole genome data), were carriers of at least two rare/common risk variants in the analyzed candidate genes panel, excluding the full penetrant mutations.ConclusionThis study suggests that EOD patients without full penetrant mutations are characterized by higher probability to carry polygenic risk alleles that patients with LOAD forms. This finding is in line with recently reported evidence, thus suggesting that the genetic risk factors identified in LOAD might modulate the risk also in EOAD.

Background: It has been suggested that oxidative stress may have a role in the pathogenesis of Alzheimer's disease (AD). Serum uric acid (UA) could exert neuroprotective effects via its antioxidant capacities. Many studies investigated serum UA levels in subjects with AD, but to date, results are conflicting and evidence in old age subjects is weak. Aims: In this study, we assess whether serum UA levels would be altered in the AD old age subjects compared to those of initial cognitive impairment and healthy controls. Methods: This is a retrospective study with data gathered from the ReGAl 2.0 project (Rete Geriatrica Alzheimer-Geriatric Network on Alzheimer's disease), a large Italian multicentric clinical-based study. A cohort of 232 subjects, including 65 (healthy controls HC), 95 mild cognitive impairment (MCI), and 72 AD, were included in the study. Serum UA was measured in all subjects by routine laboratory method. Results: The sample population includes 232 subjects, mostly women with a mean age of 79.16 ± 5.64 (range 66–93) years. No significant difference was found in gender distribution between groups. No significant correlation was found in all populations between age and uric acid levels. AD group had significantly lower UA levels as compared with HC. The association of uric acid with AD presence after adjusting for age, gender, body mass index (BMI) and creatinine levels showed that uric acid level was independently associated with the diagnosis of AD. Conclusions: These data indicate that serum UA is reduced in AD, supporting that UA may have a potential protective role against AD in old age. [ABSTRACT FROM AUTHOR]

Background: Early onset dementias (EOD) are rare neurodegenerative dementias that present before 65 years. Genetic factors have a substantially higher pathogenetic contribution in EOD patients than in late onset dementia.Objective: To identify known and/or novel rare variants in major candidate genes associated to EOD by high-throughput sequencing. Common-risk variants of apolipoprotein E (APOE) and prion protein (PRNP) genes were also assessed.Methods: We studied 22 EOD patients recruited in Memory Clinics, in the context of studies investigating genetic forms of dementia. Two methodological approaches were applied for the target-Next Generation Sequencing (NGS) analysis of these patients. In addition, we performed progranulin plasma dosage, C9Orf72 hexanucleotide repeat expansion analysis, and APOE genotyping.Results: We detected three rare known pathogenic mutations in the GRN and PSEN2 genes and eleven unknown-impact mutations in the GRN, VCP, MAPT, FUS, TREM2, and NOTCH3 genes. Six patients were carriers of only common risk variants (APOE and PRNP), and one did not show any risk mutation/variant. Overall, 69% (n = 9) of our early onset Alzheimer's disease (EAOD) patients, compared with 34% (n = 13) of sporadic late onset Alzheimer's disease (LOAD) patients and 27% (n = 73) of non-affected controls (ADNI, whole genome data), were carriers of at least two rare/common risk variants in the analyzed candidate genes panel, excluding the full penetrant mutations.Conclusion: This study suggests that EOD patients without full penetrant mutations are characterized by higher probability to carry polygenic risk alleles that patients with LOAD forms. This finding is in line with recently reported evidence, thus suggesting that the genetic risk factors identified in LOAD might modulate the risk also in EOAD. [ABSTRACT FROM AUTHOR]