The miniature CRISPR-Cas12m effector binds DNA to block transcription.

CRISPR-Cas are prokaryotic adaptive immune systems. Cas nucleases generally use CRISPR-derived RNA guides to specifically bind and cleave DNA or RNA targets. Here, we describe the experimental characterization of a bacterial CRISPR effector protein Cas12m representing subtype V-M. Despite being less than half the size of Cas12a, Cas12m catalyzes auto-processing of a crRNA guide, recognizes a 5'-TTN' protospacer-adjacent motif (PAM), and stably binds a guide-complementary double-stranded DNA (dsDNA). Cas12m has a RuvC domain with a non-canonical catalytic site and accordingly is incapable of guide-dependent cleavage of target nucleic acids. Despite lacking target cleavage activity, the high binding affinity of Cas12m to dsDNA targets allows for interference as demonstrated by its ability to protect bacteria against invading plasmids through silencing invader transcription and/or replication. Based on these molecular features, we repurposed Cas12m by fusing it to a cytidine deaminase that resulted in base editing within a distinct window.

PAH deficient pathology in humanized c.1066-11G>A phenylketonuria mice.

We have generated using CRISPR/Cas9 technology a partially humanized mouse model of the neurometabolic disease phenylketonuria (PKU), carrying the highly prevalent PAH variant c.1066-11G>A. This variant creates an alternative 3' splice site, leading to the inclusion of 9 nucleotides coding for 3 extra amino acids between Q355 and Y356 of the protein. Homozygous Pah c.1066-11A mice, with a partially humanized intron 10 sequence with the variant, accurately recapitulate the splicing defect and present almost undetectable hepatic PAH activity. They exhibit fur hypopigmentation, lower brain and body weight and reduced survival. Blood and brain phenylalanine levels are elevated, along with decreased tyrosine, tryptophan and monoamine neurotransmitter levels. They present behavioral deficits, mainly hypoactivity and diminished social interaction, locomotor deficiencies and an abnormal hind-limb clasping reflex. Changes in the morphology of glial cells, increased GFAP and Iba1 staining signals and decreased myelinization are observed. Hepatic tissue exhibits nearly absent PAH protein, reduced levels of chaperones DNAJC12 and HSP70 and increased autophagy markers LAMP1 and LC3BII, suggesting possible coaggregation of mutant PAH with chaperones and subsequent autophagy processing. This PKU mouse model with a prevalent human variant represents a useful tool for pathophysiology research and for novel therapies development.

Exploring miRNA-target gene pair detection in disease with coRmiT.

A wide range of approaches can be used to detect micro RNA (miRNA)-target gene pairs (mTPs) from expression data, differing in the ways the gene and miRNA expression profiles are calculated, combined and correlated. However, there is no clear consensus on which is the best approach across all datasets. Here, we have implemented multiple strategies and applied them to three distinct rare disease datasets that comprise smallRNA-Seq and RNA-Seq data obtained from the same samples, obtaining mTPs related to the disease pathology. All datasets were preprocessed using a standardized, freely available computational workflow, DEG_workflow. This workflow includes coRmiT, a method to compare multiple strategies for mTP detection. We used it to investigate the overlap of the detected mTPs with predicted and validated mTPs from 11 different databases. Results show that there is no clear best strategy for mTP detection applicable to all situations. We therefore propose the integration of the results of the different strategies by selecting the one with the highest odds ratio for each miRNA, as the optimal way to integrate the results. We applied this selection-integration method to the datasets and showed it to be robust to changes in the predicted and validated mTP databases. Our findings have important implications for miRNA analysis. coRmiT is implemented as part of the ExpHunterSuite Bioconductor package available from https://bioconductor.org/packages/ExpHunterSuite.

Pathogenic variants in GCSH encoding the moonlighting H-protein cause combined nonketotic hyperglycinemia and lipoate deficiency.

Maintaining protein lipoylation is vital for cell metabolism. The H-protein encoded by GCSH has a dual role in protein lipoylation required for bioenergetic enzymes including pyruvate dehydrogenase and 2-ketoglutarate dehydrogenase, and in the one-carbon metabolism through its involvement in glycine cleavage enzyme system, intersecting two vital roles for cell survival. Here, we report six patients with biallelic pathogenic variants in GCSH and a broad clinical spectrum ranging from neonatal fatal glycine encephalopathy to an attenuated phenotype of developmental delay, behavioral problems, limited epilepsy and variable movement problems. The mutational spectrum includes one insertion c.293-2_293-1insT, one deletion c.122_(228 + 1_229-1) del, one duplication of exons 4 and 5, one nonsense variant p.Gln76*and four missense p.His57Arg, p.Pro115Leu and p.Thr148Pro and the previously described p.Met1?. Via functional studies in patient's fibroblasts, molecular modeling, expression analysis in GCSH knockdown COS7 cells and yeast, and in vitro protein studies, we demonstrate for the first time that most variants identified in our cohort produced a hypomorphic effect on both mitochondrial activities, protein lipoylation and glycine metabolism, causing combined deficiency, whereas some missense variants affect primarily one function only. The clinical features of the patients reflect the impact of the GCSH changes on any of the two functions analyzed. Our analysis illustrates the complex interplay of functional and clinical impact when pathogenic variants affect a multifunctional protein involved in two metabolic pathways and emphasizes the value of the functional assays to select the treatment and investigate new personalized options.

Significance of utilizing in silico structural analysis and phenotypic data to characterize phenylalanine hydroxylase variants: A PAH landscape.

Phenylketonuria (PKU) is a genetic disorder caused by variations in the phenylalanine hydroxylase (PAH) gene. Among the 3369 reported PAH variants, 33.7% are missense alterations. Unfortunately, 30% of these missense variants are classified as variants of unknown significance (VUS), posing challenges for genetic risk assessment. In our study, we focused on analyzing 836 missense PAH variants following the American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines specified by ClinGen PAH Variant Curation Expert Panel (VCEP) criteria. We utilized and compared variant annotator tools like Franklin and Varsome, conducted 3D structural analysis of PAH, and examined active and regulatory site hotspots. In addition, we assessed potential splicing effect of apparent missense variants. By evaluating phenotype data from 22962 PKU patients, our aim was to reassess the pathogenicity of missense variants. Our comprehensive approach successfully reclassified 309 VUSs out of 836 missense variants as likely pathogenic or pathogenic (37%), upgraded 370 likely pathogenic variants to pathogenic, and reclassified one previously considered likely benign variant as likely pathogenic. Phenotypic information was available for 636 missense variants, with 441 undergoing 3D structural analysis and active site hotspot identification for 180 variants. After our analysis, only 6% of missense variants were classified as VUSs, and three of them (c.23A>C/p.Asn8Thr, c.59_60delinsCC/p.Gln20Pro, and c.278A >T/p.Asn93Ile) may be influenced by abnormal splicing. Moreover, a pathogenic variant (c.168G>T/p.Glu56Asp) was identified to have a risk exceeding 98% for modifications of the consensus splice site, with high scores indicating a donor loss of 0.94. The integration of ACMG/AMP guidelines with in silico structural analysis and phenotypic data significantly reduced the number of missense VUSs, providing a strong basis for genetic counseling and emphasizing the importance of metabolic phenotype information in variant curation. This study also sheds light on the current landscape of PAH variants.

The relations among prosocial behavior, hedonic, and eudaimonic well-being in everyday life.

INTRODUCTION: Existing research highlights the significance of prosocial behavior (voluntary, intentional behavior that results in benefits for another) to people's well-being. Yet, the extent to which this expected positive relation operates at the within-person level (e.g., is more prosocial behavior than usual related to a higher than usual level of well-being?) while taking into account stable interindividual differences, remains a research question that deserves further investigation. In this study, we aimed to explore the relations between prosocial behavior and hedonic (HWB; subjective assessment of life satisfaction and happiness) and eudaimonic (EWB; actualization of human potential in alignment with personal goals, including concepts like meaning in life and closeness to others) well-being in daily life. METHOD: Using ecological momentary assessment for 4 weeks, data were collected from two British samples, comprising 82 adolescents and 166 adults. RESULTS: Dynamic Structural Equation Modeling revealed a positive relations between prosocial behavior and HWB/EWB at both between and within-person levels across the samples. CONCLUSION: In summary, these findings further support the positive link between prosocial behavior and well-being in everyday life. Notably, this association was consistent across different age groups (adolescent and adults) at both between and within-person levels.

Metabolic Rewiring and Altered Glial Differentiation in an iPSC-Derived Astrocyte Model Derived from a Nonketotic Hyperglycinemia Patient.

The pathophysiology of nonketotic hyperglycinemia (NKH), a rare neuro-metabolic disorder associated with severe brain malformations and life-threatening neurological manifestations, remains incompletely understood. Therefore, a valid human neural model is essential. We aimed to investigate the impact of GLDC gene variants, which cause NKH, on cellular fitness during the differentiation process of human induced pluripotent stem cells (iPSCs) into iPSC-derived astrocytes and to identify sustainable mechanisms capable of overcoming GLDC deficiency. We developed the GLDC27-FiPS4F-1 line and performed metabolomic, mRNA abundance, and protein analyses. This study showed that although GLDC27-FiPS4F-1 maintained the parental genetic profile, it underwent a metabolic switch to an altered serine-glycine-one-carbon metabolism with a coordinated cell growth and cell cycle proliferation response. We then differentiated the iPSCs into neural progenitor cells (NPCs) and astrocyte-lineage cells. Our analysis showed that GLDC-deficient NPCs had shifted towards a more heterogeneous astrocyte lineage with increased expression of the radial glial markers GFAP and GLAST and the neuronal markers MAP2 and NeuN. In addition, we detected changes in other genes related to serine and glycine metabolism and transport, all consistent with the need to maintain glycine at physiological levels. These findings improve our understanding of the pathology of nonketotic hyperglycinemia and offer new perspectives for therapeutic options.

The Genetic Landscape and Epidemiology of Phenylketonuria.

Phenylketonuria (PKU), caused by variants in the phenylalanine hydroxylase (PAH) gene, is the most common autosomal-recessive Mendelian phenotype of amino acid metabolism. We estimated that globally 0.45 million individuals have PKU, with global prevalence 1:23,930 live births (range 1:4,500 [Italy]-1:125,000 [Japan]). Comparing genotypes and metabolic phenotypes from 16,092 affected subjects revealed differences in disease severity in 51 countries from 17 world regions, with the global phenotype distribution of 62% classic PKU, 22% mild PKU, and 16% mild hyperphenylalaninemia. A gradient in genotype and phenotype distribution exists across Europe, from classic PKU in the east to mild PKU in the southwest and mild hyperphenylalaninemia in the south. The c.1241A>G (p.Tyr414Cys)-associated genotype can be traced from Northern to Western Europe, from Sweden via Norway, to Denmark, to the Netherlands. The frequency of classic PKU increases from Europe (56%) via Middle East (71%) to Australia (80%). Of 758 PAH variants, c.1222C>T (p.Arg408Trp) (22.2%), c.1066-11G>A (IVS10-11G>A) (6.4%), and c.782G>A (p.Arg261Gln) (5.5%) were most common and responsible for two prevalent genotypes: p.[Arg408Trp];[Arg408Trp] (11.4%) and c.[1066-11G>A];[1066-11G>A] (2.6%). Most genotypes (73%) were compound heterozygous, 27% were homozygous, and 55% of 3,659 different genotypes occurred in only a single individual. PAH variants were scored using an allelic phenotype value and correlated with pre-treatment blood phenylalanine concentrations (n = 6,115) and tetrahydrobiopterin loading test results (n = 4,381), enabling prediction of both a genotype-based phenotype (88%) and tetrahydrobiopterin responsiveness (83%). This study shows that large genotype databases enable accurate phenotype prediction, allowing appropriate targeting of therapies to optimize clinical outcome.

Prevalence of DDC genotypes in patients with aromatic L-amino acid decarboxylase (AADC) deficiency and in silico prediction of structural protein changes.

Aromatic L-amino acid decarboxylase (AADC) deficiency is a rare autosomal recessive genetic disorder affecting the biosynthesis of dopamine, a precursor of both norepinephrine and epinephrine, and serotonin. Diagnosis is based on the analysis of CSF or plasma metabolites, AADC activity in plasma and genetic testing for variants in the DDC gene. The exact prevalence of AADC deficiency, the number of patients, and the variant and genotype prevalence are not known. Here, we present the DDC variant (n = 143) and genotype (n = 151) prevalence of 348 patients with AADC deficiency, 121 of whom were previously not reported. In addition, we report 26 new DDC variants, classify them according to the ACMG/AMP/ACGS recommendations for pathogenicity and score them based on the predicted structural effect. The splice variant c.714+4A>T, with a founder effect in Taiwan and China, was the most common variant (allele frequency = 32.4%), and c.[714+4A>T];[714+4A>T] was the most common genotype (genotype frequency = 21.3%). Approximately 90% of genotypes had variants classified as pathogenic or likely pathogenic, while 7% had one VUS allele and 3% had two VUS alleles. Only one benign variant was reported. Homozygous and compound heterozygous genotypes were interpreted in terms of AADC protein and categorized as: i) devoid of full-length AADC, ii) bearing one type of AADC homodimeric variant or iii) producing an AADC protein population composed of two homodimeric and one heterodimeric variant. Based on structural features, a score was attributed for all homodimers, and a tentative prediction was advanced for the heterodimer. Almost all AADC protein variants were pathogenic or likely pathogenic.

Pathogenic variants of the coenzyme A biosynthesis-associated enzyme phosphopantothenoylcysteine decarboxylase cause autosomal-recessive dilated cardiomyopathy.

Coenzyme A (CoA) is an essential cofactor involved in a range of metabolic pathways including the activation of long-chain fatty acids for catabolism. Cells synthesize CoA de novo from vitamin B5 (pantothenate) via a pathway strongly conserved across prokaryotes and eukaryotes. In humans, it involves five enzymatic steps catalyzed by four enzymes: pantothenate kinase (PANK [isoforms 1-4]), 4'-phosphopantothenoylcysteine synthetase (PPCS), phosphopantothenoylcysteine decarboxylase (PPCDC), and CoA synthase (COASY). To date, inborn errors of metabolism associated with all of these genes, except PPCDC, have been described, two related to neurodegeneration with brain iron accumulation (NBIA), and one associated with a cardiac phenotype. This paper reports another defect in this pathway (detected in two sisters), associated with a fatal cardiac phenotype, caused by biallelic variants (p.Thr53Pro and p.Ala95Val) of PPCDC. PPCDC enzyme (EC 4.1.1.36) catalyzes the decarboxylation of 4'-phosphopantothenoylcysteine to 4'-phosphopantetheine in CoA biosynthesis. The variants p.Thr53Pro and p.Ala95Val affect residues highly conserved across different species; p.Thr53Pro is involved in the binding of flavin mononucleotide, and p.Ala95Val is likely a destabilizing mutation. Patient-derived fibroblasts showed an absence of PPCDC protein, and nearly 50% reductions in CoA levels. The cells showed clear energy deficiency problems, with defects in mitochondrial respiration, and mostly glycolytic ATP synthesis. Functional studies performed in yeast suggest these mutations to be functionally relevant. In summary, this work describes a new, ultra-rare, severe inborn error of metabolism due to pathogenic variants of PPCDC.

Neuropathological Findings in Short-Chain enoyl-CoA Hydratase 1 Deficiency (ECHS1D): Case Report and Differential Diagnosis.

Short-chain enoyl-CoA hydratase 1 (ECHS1) is an enzyme that participates in the metabolism of valine, transforming methacrylyl-CoA in ß-hydroxy-isobutyryl-CoA. There is an accumulation of intermediate acids and ammonium as a consequence of its deficit. This background generates a harmful environment for the brain causing neuronal death and severe brain lesions. We present a case of a 39 weeks newborn that died at 31 hours old. We found vacuolization in basal areas, brain stem, cerebellum and spinal cord white matter (spongiform myelinopathy). These vacuoles were periodic acid-Schiff stain negative, there were neither acompanion gliosis nor macrophagic reaction. These findings were suggestive of metabolism acid disorders. The final diagnosis was confirmed by genetic study by massive parallel sequencing, showing 2 previously described pathogenic variants (c.160C > T and c.394G > A) of short-chain enoyl-CoA hydratase 1 gene. To our knowledge, this is the first case reporting the histological changes in short-chain enoyl-CoA hydratase 1 deficiency. Histological study provides useful information to orientate the diagnostic and clarify the clinical manifestations, especially in hospitals where urine or blood samples are not taking routinely or where genetic studies may not be performed.Synopsis: The main neuropathological findings in Short-chain enoyl-CoA hydratase 1 deficiency are the presence of whitte matter vacuoles in basal areas, brain stem and spinal cord.

Dual latent tuberculosis screening with tuberculin skin tests and QuantiFERON-TB assays before TNF-α inhibitor initiation in children in Spain.

Tumor-necrosis-factor-α inhibitors (anti-TNF-α) are associated with an increased risk of tuberculosis (TB) disease, primarily due to reactivation of latent TB infection (LTBI). We assessed the performance of parallel LTBI screening with tuberculin skin test (TST) and QuantiFERON-TB Gold In-Tube assays (QFT-GIT) before anti-TNF-α treatment in children with immune-mediated inflammatory disorders in a low TB-burden setting. We conducted a multicenter cohort study involving 17 pediatric tertiary centers in Spain. LTBI was defined as the presence of a positive TST and/or QFT-GIT result without clinical or radiological signs of TB disease. A total of 270 patients (median age:11.0 years) were included, mainly with rheumatological (55.9%) or inflammatory bowel disease (34.8%). Twelve patients (4.4%) were diagnosed with TB infection at screening (LTBI, n = 11; TB disease, n = 1). Concordance between TST and QFT-GIT results was moderate (TST+/QFT-GIT+, n = 4; TST-/QFT-GIT+, n = 3; TST+/QFT-GIT-, n = 5; kappa coefficient: 0.48, 95% CI: 0.36-0.60). Indeterminate QFT-GIT results occurred in 10 patients (3.7%) and were associated with young age and elevated C-reactive protein concentrations. Eleven of 12 patients with TB infection uneventfully completed standard LTBI or TB treatment. During a median follow-up period of 6.4 years, only 2 patients developed TB disease (incidence density: 130 (95% CI: 20-440) per 100,000 person-years), both probable de novo infections. CONCLUSION: A substantial number of patients were diagnosed with LTBI during screening. The dual strategy identified more cases than either of the tests alone, and test agreement was only moderate. Our data show that in children in a low TB prevalence setting, a dual screening strategy with TST and IGRA before anti-TNF-α treatment is effective. WHAT IS KNOWN: • The optimal screening strategy for latent tuberculosis in children with immune-mediated inflammatory disorders remains uncertain. • Children receiving anti-TNF-α drugs are at increased risk of developing severe tuberculosis disease. WHAT IS NEW: • A dual screening strategy, using TST and an IGRA assay, identified more children with latent tuberculosis than either of the tests alone. • Identification and treatment of latent tuberculosis before initiation of anti-TNF-α therapy averted incident tuberculosis cases.

What do I want to feel? Emotion goals in childhood, adolescence, and adulthood.

Beliefs about emotion utility can influence context-sensitive emotion goals (i.e., desired emotional responses). Although key for emotion regulation, emotion goals have been overlooked in children and adolescents. In 2018-2019 results of Studies 1 and 2 showed that children (N = 192, Mage  = 8.65, 47% girls, 96% White) were less motivated by and found anger less useful in confrontation than adolescents (N = 192, Mage  = 12.96, 50% girls, 93% White) and adults (N = 195, Mage  = 29.82, 51% women, 96% White). The link between emotion goals and beliefs about emotion utility was weaker in children. In 2021, Study 3 (N = 60, 8-year-olds, 47% girls, 90% White) ruled out expectations as a possible explanation for the previous findings. Context-sensitive utility of emotions may be acquired during development.

The effect of face mask wearing on language processing and emotion recognition in young children.

Face mask wearing was an important preventative strategy for the transmission of the COVID-19 virus. However, the effects that occluding the mouth and nose area with surgical masks could have on young children's language processing and emotion recognition skills have received little investigation. To evaluate the possible effects, the current study recruited a sample of 74 children from the North West of England (aged 4-8 years). They completed two computer-based tasks with adults wearing or not wearing surgical face masks to assess (a) language processing skills and (b) emotion recognition ability. To control for individual differences, age, sex, receptive vocabulary, early reading skills, and parent-reported social-emotional competence were included in analyses. The findings from the study highlighted that although younger children were less accurate than older children, face masks did not significantly impair basic language processing ability. However, they had a significant effect on the children's emotion recognition accuracy-with masked angry faces more easily recognized and masked happy and sad faces less easily recognized. Children's age and social-emotional skills also played a role. The findings suggest that the effects of face masks should continue to be evaluated.

Streamlined CRISPR genome engineering in wild-type bacteria using SIBR-Cas.

CRISPR-Cas is a powerful tool for genome editing in bacteria. However, its efficacy is dependent on host factors (such as DNA repair pathways) and/or exogenous expression of recombinases. In this study, we mitigated these constraints by developing a simple and widely applicable genome engineering tool for bacteria which we termed SIBR-Cas (Self-splicing Intron-Based Riboswitch-Cas). SIBR-Cas was generated from a mutant library of the theophylline-dependent self-splicing T4 td intron that allows for tight and inducible control over CRISPR-Cas counter-selection. This control delays CRISPR-Cas counter-selection, granting more time for the editing event (e.g. by homologous recombination) to occur. Without the use of exogenous recombinases, SIBR-Cas was successfully applied to knock-out several genes in three wild-type bacteria species (Escherichia coli MG1655, Pseudomonas putida KT2440 and Flavobacterium IR1) with poor homologous recombination systems. Compared to other genome engineering tools, SIBR-Cas is simple, tightly regulated and widely applicable for most (non-model) bacteria. Furthermore, we propose that SIBR can have a wider application as a simple gene expression and gene regulation control mechanism for any gene or RNA of interest in bacteria.

Dysregulated Cell Homeostasis and miRNAs in Human iPSC-Derived Cardiomyocytes from a Propionic Acidemia Patient with Cardiomyopathy.

Propionic acidemia (PA) disorder shows major involvement of the heart, among other alterations. A significant number of PA patients develop cardiac complications, and available evidence suggests that this cardiac dysfunction is driven mainly by the accumulation of toxic metabolites. To contribute to the elucidation of the mechanistic basis underlying this dysfunction, we have successfully generated cardiomyocytes through the differentiation of induced pluripotent stem cells (iPSCs) from a PCCB patient and its isogenic control. In this human cellular model, we aimed to examine microRNAs (miRNAs) profiles and analyze several cellular pathways to determine miRNAs activity patterns associated with PA cardiac phenotypes. We have identified a series of upregulated cardiac-enriched miRNAs and alterations in some of their regulated signaling pathways, including an increase in the expression of cardiac damage markers and cardiac channels, an increase in oxidative stress, a decrease in mitochondrial respiration and autophagy; and lipid accumulation. Our findings indicate that miRNA activity patterns from PA iPSC-derived cardiomyocytes are biologically informative and advance the understanding of the molecular mechanisms of this rare disease, providing a basis for identifying new therapeutic targets for intervention strategies.

Hyperuricaemia Does Not Interfere with Aortopathy in a Murine Model of Marfan Syndrome.

Redox stress is involved in the aortic aneurysm pathogenesis in Marfan syndrome (MFS). We recently reported that allopurinol, a xanthine oxidoreductase inhibitor, blocked aortopathy in a MFS mouse model acting as an antioxidant without altering uric acid (UA) plasma levels. Hyperuricaemia is ambiguously associated with cardiovascular injuries as UA, having antioxidant or pro-oxidant properties depending on the concentration and accumulation site. We aimed to evaluate whether hyperuricaemia causes harm or relief in MFS aortopathy pathogenesis. Two-month-old male wild-type (WT) and MFS mice (Fbn1C1041G/+) were injected intraperitoneally for several weeks with potassium oxonate (PO), an inhibitor of uricase (an enzyme that catabolises UA to allantoin). Plasma UA and allantoin levels were measured via several techniques, aortic root diameter and cardiac parameters by ultrasonography, aortic wall structure by histopathology, and pNRF2 and 3-NT levels by immunofluorescence. PO induced a significant increase in UA in blood plasma both in WT and MFS mice, reaching a peak at three and four months of age but decaying at six months. Hyperuricaemic MFS mice showed no change in the characteristic aortic aneurysm progression or aortic wall disarray evidenced by large elastic laminae ruptures. There were no changes in cardiac parameters or the redox stress-induced nuclear translocation of pNRF2 in the aortic tunica media. Altogether, the results suggest that hyperuricaemia interferes neither with aortopathy nor cardiopathy in MFS mice.

Mucosal Immune Defence Gene Polymorphisms as Relevant Players in the Pathogenesis of IgA Vasculitis?

ITGAM-ITGAX (rs11150612, rs11574637), VAV3 rs17019602, CARD9 rs4077515, DEFA (rs2738048, rs10086568), and HORMAD2 rs2412971 are mucosal immune defence polymorphisms, that have an impact on IgA production, described as risk loci for IgA nephropathy (IgAN). Since IgAN and Immunoglobulin-A vasculitis (IgAV) share molecular mechanisms, with the aberrant deposit of IgA1 being the main pathophysiologic feature of both entities, we assessed the potential influence of the seven abovementioned polymorphisms on IgAV pathogenesis. These seven variants were genotyped in 381 Caucasian IgAV patients and 997 matched healthy controls. No statistically significant differences were observed in the genotype and allele frequencies of these seven polymorphisms when the whole cohort of IgAV patients and those with nephritis were compared to controls. Similar genotype and allele frequencies of all polymorphisms were disclosed when IgAV patients were stratified according to the age at disease onset or the presence/absence of gastrointestinal or renal manifestations. Likewise, no ITGAM-ITGAX and DEFA haplotype differences were observed when the whole cohort of IgAV patients, along with those with nephritis and controls, as well as IgAV patients, stratified according to the abovementioned clinical characteristics, were compared. Our results suggest that mucosal immune defence polymorphisms do not represent novel genetic risk factors for IgAV pathogenesis.

Severe outbreak of ulcerative colitis and cerebral neoplasia. Difficult management in COVID time.

A 61-year-old male diabetic patient, diagnosed with ulcerative colitis (UC) 30 years ago, currently under treatment with mesalazine is presented. He was admitted to the emergency department due to a severe outbreak of UC, with 15 depositions daily, rectal bleeding and poor general condition. A brain CT-scan was carried out in the emergency department due to a sudden self-limited aphasia. A left frontal lesion of 45x38 mms with a prominent perilesional edema and with a displacement of the midline was reported. This was believed to be a meningioma (figure 1A). Urgent neurosurgery was not performed, prioritizing the severe flare-up UC. Based on this, full-dose metilprednisolone was administered.

A functional platform for the selection of pathogenic variants of PMM2 amenable to rescue via the use of pharmacological chaperones.

Different strategies are being investigated for treating PMM2-CDG, the most common congenital disorder of glycosylation. The use of pharmacochaperones (PCs) is one of the most promising. The present work characterizes the expression, stability, and enzymatic properties of 15 previously described clinical variants of the PMM2 protein, four novel variants, the Pmm2 mouse variant p.Phe115Leu, and its p.Phe119Leu human counterpart, with the aim of extending the potential use of pharmacochaperoning treatment. PMM2 variants were purified as stable homodimers, except for p.Asp65Gly, p.Ile120Thr, and p.Thr237Lys (no expression detected), p.Thr226Ser and p.Val231Met (aggregates), and p.Glu93Ala, p.Phe119Leu, and p.Phe115Leu (partial dissociated). Enzyme activity analyses identified severe variants and milder ones. Pure dimeric mutant proteins showed a reduction in thermal stability except for p.Asn216Asp. The thermal stability of all the unstable mutants was recovered in the presence of the PC compound VIII. This study adds to the list of destabilizing human variants amenable to rescue by small chemical compounds that increase the stability/activity of PMM2. The proposed platform can be reliably used for assessing the disease-causing effects of PMM2 missense variants, for assessing the correlation between genotype and phenotype, for confirming new clinical defects, and for identifying destabilizing mutations amenable to rescue by PCs.