Significance: At atomic and molecular levels, particles interact via the immutable laws of quantum mechanics, whereas at nanoscopic and microscopic levels, interactions between colloidal particles can be determined by human design. We exploit DNA self-assembly to produce nanoscopic particles with a controlled number of interacting terminations, providing the particles with valence. Experimental investigation of the collective behavior of such colloids shows that reducing the number of interacting sites results in a significant shrinkage of the gas–liquid coexistence region, with critical parameters decreasing as the valence is reduced. We also observe an unconventional dynamic behavior in the proximity of the critical point. Such findings are relevant to answer fundamental physics issues and potentially to determine the stability region of new DNA-based materials.

Congenital hypothyroidism (CH), the most frequent form of preventable mental retardation, is predicted to have a relevant genetic origin. However, CH is frequently reported to be sporadic and candidate gene variations were found in <10% of the investigated patients. Here, we characterize the involvement of 11 candidate genes through a systematic Next Generation Sequencing (NGS) analysis. The NGS was performed in 177 unrelated CH patients (94 gland-in-situ; 83 dysgenesis) and in 3,538 control subjects. Non-synonymous or splicing rare variants (MAF < 0.01) were accepted, and their functional impact was predicted by a comprehensive bioinformatic approach and co-segregation studies. The frequency of variations in cases and controls was extended to 18 CH-unrelated genes. At least one rare variant was accepted in 103/177 patients. Monogenic recessive forms of the disease were found in five cases, but oligogenic involvement was detected in 39 patients. The 167 variations were found to affect all genes independently of the CH phenotype. These findings were replicated in an independent cohort of additional 145 CH cases. When compared to 3,538 controls, the CH population was significantly enriched with disrupting variants in the candidate genes (P = 5.5 × 10⁻⁷), but not with rare variations in CH-unrelated genes. Co-segregation studies of the hypothyroid phenotype with multiple gene variants in several pedigrees confirmed the potential oligogenic origin of CH. The systematic NGS approach reveals the frequent combination of rare variations in morphogenetic or functional candidate genes in CH patients independently of phenotype. The oligogenic origin represents a suitable explanation for the frequent sporadic CH occurrence.

Given the highly variable clinical phenotype of Coronavirus disease 2019 (COVID-19), a deeper analysis of the host genetic contribution to severe COVID-19 is important to improve our understanding of underlying disease mechanisms. Here, we describe an extended genome-wide association meta-analysis of a well-characterized cohort of 3255 COVID-19 patients with respiratory failure and 12 488 population controls from Italy, Spain, Norway and Germany/Austria, including stratified analyses based on age, sex and disease severity, as well as targeted analyses of chromosome Y haplotypes, the human leukocyte antigen region and the SARS-CoV-2 peptidome. By inversion imputation, we traced a reported association at 17q21.31 to a ~0.9-Mb inversion polymorphism that creates two highly differentiated haplotypes and characterized the potential effects of the inversion in detail. Our data, together with the 5th release of summary statistics from the COVID-19 Host Genetics Initiative including non-Caucasian individuals, also identified a new locus at 19q13.33, including NAPSA, a gene which is expressed primarily in alveolar cells responsible for gas exchange in the lung.

Multiple sclerosis (MS) is a complex autoimmune disease of the central nervous system characterized by chronic inflammation, demyelination, and axonal damage. As microRNA (miRNA)-dependent alterations in gene expression in hematopoietic cells are critical for mounting an appropriate immune response, miRNA deregulation may result in defects in immune tolerance. In this frame, we sought to explore the possible involvement of miRNAs in MS pathogenesis by monitoring the differential expression of 22 immunity-related miRNAs in peripheral blood mononuclear cells of MS patients and healthy controls, by using a microbead-based technology. Three miRNAs resulted >2 folds up-regulated in MS vs controls, whereas none resulted down-regulated. Interestingly, the most up-regulated miRNA (mir-155; fold change = 3.30; P = 0.013) was previously reported to be up-regulated also in MS brain lesions. Mir-155 up-regulation was confirmed by qPCR experiments. The role of mir-155 in MS susceptibility was also investigated by genotyping four single nucleotide polymorphisms (SNPs) mapping in the mir-155 genomic region. A haplotype of three SNPs, corresponding to a 12-kb region encompassing the last exon of BIC (the B-cell Integration Cluster non-coding RNA, from which mir-155 is processed), resulted associated with the disease status (P = 0.035; OR = 1.36, 95% CI = 1.05–1.77), suggesting that this locus strongly deserves further investigations.

Abnormalities in alternative splicing (AS) are emerging as recurrent features in autoimmune diseases (AIDs). In particular, a growing body of evidence suggests the existence of a pathogenic association between a generalized defect in splicing regulatory genes and multiple sclerosis (MS). Moreover, several studies have documented an unbalance in alternatively-spliced isoforms in MS patients possibly contributing to the disease etiology. In this work, using a combination of PCR-based techniques (reverse-transcription (RT)-PCR, fluorescent-competitive, real-time, and digital RT-PCR assays), we investigated the alternatively-spliced gene encoding Gasdermin B, GSDMB, which was repeatedly associated with susceptibility to asthma and AIDs. The in-depth characterization of GSDMB AS and backsplicing profiles led us to the identification of an exonic circular RNA (ecircRNA) as well as of novel GSDMB in-frame and out-of-frame isoforms. The non-productive splicing variants were shown to be downregulated by the nonsense-mediated mRNA decay (NMD) in human cell lines, suggesting that GSDMB levels are significantly modulated by NMD. Importantly, both AS isoforms and the identified ecircRNA were significantly dysregulated in peripheral blood mononuclear cells of relapsing-remitting MS patients compared to controls, further supporting the notion that aberrant RNA metabolism is a characteristic feature of the disease.

Factor XI (FXI) deficiency is an autosomal bleeding disorder, usually post trauma or surgery, characterized by reduced levels of coagulation FXI in plasma. The disease is highly prevalent in Ashkenazi Jews (heterozygote frequency ~9%), whereas it is considered a rare condition in most populations (prevalence of the severe deficiency: 1:10⁶ in Caucasians). So far, >190 causative mutations have been identified throughout the F11 gene. To have a global landscape of genetic variation of F11, we explored publicly-available exome-based data obtained from >60,000 individuals belonging to different ethnicities (Exome Aggregation Consortium resource). This analysis revealed profound differences in heterozygote frequencies among populations [African allele frequency (AF)=0.0016; East-Asian AF=0.0045; European AF=0.0036; Finnish AF=0.00030; Latino AF=0.0021; South-Asian AF=0.0015], and a prevalence significantly higher than that reported so far (e.g. the calculated prevalence of the severe deficiency in Europeans would be: 12.9 in 10⁶). In addition, this analysis allowed us to evidence recurrent and ethnic-specific mutations: i) p.Phe223Leu in Africans (23.5% of all mutated alleles), p.Gln263X and p.Leu424CysfsX in East Asians (28.2 and 20.5%, respectively), and p.Ala412Thr in Latinos (25%). Key points Exome-data analysis revealed that FXI deficiency is from two to twenty times more frequent than expected in most populations. Exome-data analysis evidenced novel recurrent and ethnic-specific mutations other than the well-known type-II and type-III defects.