Genetics of inborn errors of immunity: Diagnostic strategies and new approaches to CNV detection.

BACKGROUND: Genetic diagnosis of inborn errors of immunity (IEI) is complex due to the large number of genes involved and their molecular features. Missense variants have been reported as the most common cause of IEI. However, the frequency of copy number variants (CNVs) may be underestimated since their detection requires specific quantitative techniques. At this point, the use of Next Generation Sequencing (NGS) is acquiring relevance. METHODS: In this article, we present our experience in the genetic diagnosis of IEI based on three diagnostic algorithms that allowed the detection of single nucleotide variants (SNVs) and CNVs. Following this approximation, 703 index cases were evaluated between 2014 and 2021. Sanger sequencing, MLPA, CGH array, breakpoint spanning PCR or a customized NGS-based multigene-targeted panel were performed. RESULTS: A genetic diagnosis was reached in 142 of the 703 index cases (20%), 19 of them presented deletions as causal variants. Deletions were also detected in 5 affected relatives and 16 healthy carriers during the family studies. Additionally, we compile, characterize and present all the CNVs detected by our diagnostic algorithms, representing the largest cohort of deletions related to IEI to date. Furthermore, three bioinformatic tools (LACONv, XHMM, VarSeq™) based on NGS data were evaluated. VarSeq™ was the most sensitive and specific bioinformatic tool; detecting 21/23 (91%) deletions located in captured regions. CONCLUSION: Based on our results, we propose a strategy to guide the molecular diagnosis that can be followed by expert and non-expert centres in the field of IEI.

Role of Inflammatory Cytokines in the Conversion of Mild Cognitive Impairment to Dementia: A Prospective Study.

BACKGROUND: The effect that cytokines can exert on the progression from mild cognitive impairment (MCI) to ongoing dementia is a matter of debate and the results obtained so far are controversial. OBJECTIVE: The aim of the study is to analyze the influence of markers of subclinical inflammation on the progression of MCI to dementia. METHODS: A prospective study involving a cohort of patients ≥ 65 years of age diagnosed with MCI and followed for 3 years was conducted. 105 patients were enrolled, and serum concentrations of several subclinical inflammatory markers were determined. RESULTS: After 3.09 (2 - 3.79) years of follow-up, 47 (44.76%) patients progressed to dementia. Alpha 1-antichymotrypsin (ACT) was found to be significantly higher in patients who progressed to dementia (486.45 ± 169.18 vs. 400.91 ± 163.03; p = 0.012), and observed to significantly increase the risk of developing dementia in patients with mild cognitive impairment (1.004, 1.001-1.007; p = 0.007). IL-10 levels were significantly higher in those who remained stable (6.69 ± 18.1 vs. 32.54 ± 89.6; p = 0.04). Regarding the type of dementia to which our patients progressed, we found that patients who developed mixed dementia had higher IL-4 levels than those who converted to AD (31.54 ± 63.6 vs. 4.43 ± 12.9; p = 0.03). No significant differences were observed between the groups with regard to the ESR and LPa, CRP, IL-1 and TNF-α levels. CONCLUSION: ACT levels have a significant predictive value in the conversion of MCI to dementia. IL-10 levels could be a protective factor. It is necessary to conduct studies with serial determinations of these and other inflammatory markers in order to determine their effect on the progression of MCI to dementia.

Association of vascular factors and amnestic mild cognitive impairment: a comprehensive approach.

BACKGROUND AND OBJECTIVE: Current evidence shows that numerous classic vascular risk factors (VRF) contribute to mild cognitive impairment (MCI), but the effects of emerging VRFs are less well-known. Using a comprehensive approach, we assessed the frequency and strength of association between MCI and classic VRFs, subclinical markers of atherosclerosis (cystatin C, lipoprotein(a), high-sensitivity C-reactive protein, and intima-media thickness) and white matter hyperintensities (WMH). METHODS: In this case-control study of consecutive MCI patients and cognitively normal controls, subjects underwent clinical and neuropsychological examinations, laboratory analyses, a carotid duplex scan, and a brain magnetic resonance imaging scan. RESULTS: The study included 105 patients with amnestic MCI (aMCI): 24 with single domain amnestic MCI, 81 with multiple domain amnestic MCI, and 76 controls. Compared to controls, patients with aMCI were significantly older and had higher rates of arterial hypertension, atrial fibrillation, and depression. They also had a larger intima-media thickness and higher load of WMHs, both periventricular (WMHpv) and subcortical (WMHsc). In the adjusted analysis, all variables except WMHsc displayed a significant association with aMCI. Body mass index exerted a protective effect. CONCLUSIONS: Our findings suggest a direct association between aMCI and age, hypertension, atrial fibrillation depression, intima-media thickness, and WMHpv. Body mass index has a protective effect on this MCI subtype.