Neopterin is a pro-inflammatory molecule upregulated in several diseases; however, its role in pathophysiology is unclear and its genetic regulation is unexplored. We observed that neopterin levels increase during senescence (P-value = 1.88×10-13, beta = 0.96) and positively correlate with age-related neurodegeneration and inflammation markers. The heritability estimation of neopterin variation was 35%. We then conducted a genome-wide association study on 999 Sardinians, identifying two signals in the GTP cyclohydrolase (GCH1) gene that were suggestively associated with neopterin levels. The first signal, led by rs140884539-C (P-value = 7.05×10-08, beta = 0.59), was in strong linkage disequilibrium with variants associated with predisposition to rheumatoid arthritis, decrease in dopamine, increased levels of GCH1 transcript, dopamine metabolites, and galectin-3. The second signal, represented by rs12323905-T (P-value = 8.17×10-08, beta = 0.30), colocalised with GCH1 splicing and Parkinson’s disease signals. Transcriptome analysis of 605 Sardinians showed that the Parkinson’s disease-predisposing variant was significantly associated with an increase in a shorter and inactive form of GCH1, whose presence is predicted to reduce the GCH1 decamer stability. The GCH1 homo-decamer regulates neopterin and tetrahydrobiopterin production, a cofactor required for the synthesis of dopamine and serotonin. Our data motivate experimental work to test whether modulating GCH1 expression or isoform ratio alters dopaminergic function in Parkinson’s disease models.

BackgroundThe immunoglobulin level following vaccination against SARS-CoV-2 results from a multifaceted immunological process involving cells and molecules that determine its efficacy and protect us against severe infection outcomes. The observed heterogeneity in the immune response to vaccination is partly attributable to host genetic factors; however, this genetic contribution has only been partially explored.MethodsTo elucidate the mechanisms underlying the antibody response elicited by the Pfizer-BioNTech vaccine, we conducted a genome-wide association study on anti-spike immunoglobulin G levels measured in 1,968 Italian individuals who received two doses of the vaccine, selected from a larger cohort of 7,169 volunteers characterized for 8 million genetic variants. Sex, age, body mass index, smoking habit, and time elapsed between vaccine administration and blood draw were accounted as covariates in the linear regression model.ResultsWe identified a novel signal of association on chromosome 3 in the intronic region of the CMTM8 gene and confirmed one previously identified at the HLA locus close to the HLA-B gene. The lead SNP in the CMTM8 gene, rs7643677 (p-value = 2.095×10-8), is associated with anti-S IgG levels and with the expression level of CD66b on granulocytic/polymorphonuclear myeloid-derived suppressor cells.ConclusionsThese findings support a role for CMTM8 in regulating the suppressive activity of specific immune cells, and suggest a potential interplay among genetic, humoral, and cellular mechanisms underlying the immune response to SARS-CoV-2 vaccination.

The severity of malaria varies substantially between individuals, but the mechanisms that underlie these differences remain unclear. Because erythrocytes have a key role in malaria biology, genetic variants associated with the development of these cells could inform the mechanisms that determine disease severity. Here we investigate the mechanistic basis of the association of the variant rs112233623-T with erythrocyte properties, and examine its role in modulating malaria severity. This variant is associated with increased levels of haemoglobin A2, increased erythrocyte size and reduced erythrocyte number1,2. It is found in an erythroid enhancer of CCND3, which encodes cyclin D3-a cell-division activator that enhances the pentose phosphate pathway and thereby helps to counteract reactive oxygen species (ROS)3. We show that rs112233623-T disrupts a binding site for the transcription factor SMAD3, weakens enhancer activity and, in erythrocyte precursors (erythroblasts), is associated with reduced CCND3 expression and inhibition of the G1-S cell-cycle transition, concomitant with a reduction in the number of erythrocytes and an increase in their size. Using population genetic methods, we observe signatures of positive selection for rs112233623-T in the genetic history of Sardinia, a region in which malaria was once prevalent. Furthermore, we show that parasite growth is impaired in cultured Plasmodium falciparum-infected erythrocytes from rs112233623-T carriers, and that this impairment correlates with ROS levels. This mirrors our observations in erythrocytes from individuals who are deficient in the pentose-phosphate-pathway enzyme G6PD-a trait associated with protection against malaria in some settings-and highlights a common ROS-based mechanism of malaria resistance. Our results suggest that a reduction in CCND3 in erythroblasts constitutes a mechanism of resistance to malaria, and could enable therapeutic interventions.

The TYK2:p.Pro1104Ala (rs34536443) hypomorph variant has been associated with protection against numerous autoimmune disorders. Thus, its mechanism of action becomes of great interest. Here, consistent with the participation of activated immune cells in autoimmunity, we show that the variant regulates the levels of immune cells at a human, general population level and is associated particularly with higher levels of T and B lymphocytes, especially the naïve (non-activated) compartment. Also, consistent with a protective function in autoimmunity, the level of regulatory CD4+ T cells was increased. Thus, this variant decreases immune activation thereby protecting from autoimmunity. Our work links the cellular mechanism regulated by the TYK2:p.Pro1104Ala variant to autoimmunity protection and supports TYK2 as a therapeutic target in autoimmunity.

BACKGROUND:Growth differentiation factor 15 (GDF-15) levels are emerging as a candidate biomarker of aging. The present study aimed to: (1) characterize the association of GDF-15 with the continuum of arterial stiffening, assessed as carotid-femoral pulse wave velocity, as age increases; (2) determine the predictive role of serum GDF-15 levels on mortality; and (3) identify genetic determinants of serum GDF-15 levels. METHODS AND RESULTS:Serum levels of GDF-15 and established cardiovascular risk factors, including pulse wave velocity, were assessed in a large (4736 individual) Sardinian population. Serum levels of GDF-15, which can be reliably measured repeatedly over time, increase with age; are associated with a stiffer aorta; "mediate" a large proportion of the age-associated increase in arterial stiffness; pose risks because of their association with greater mortality; and are significantly associated with the variant rs11549407, which causes thalassemia major in homozygosity. CONCLUSIONS:Because of its consistent ability to predict functional and clinical outcomes, including all-cause mortality, we conclude that GDF-15 serum levels serve as a robust biomarker for the continuum from health to the emergence of clinical disease during aging and, subsequently, to the likelihood of mortality.

Iron is an essential mineral that supports numerous biological functions. Studies have reported associations between iron dysregulation and certain cardiovascular and neurodegenerative diseases, but the direction of influence is not clear. Our goal was to use computational approaches to better understand the role of genetically predicted iron levels on disease risk. We meta-analyzed genome-wide association study summary statistics for serum iron levels from two cohorts and two previous meta-analyses. We then obtained summary statistics from 11 neurodegenerative, cerebrovascular, cardiovascular or lipid traits to assess global and regional genetic correlation between iron levels and these traits. We used two-sample Mendelian randomization (MR) to estimate causal effects. Sex-stratified analyses were also carried out to identify effects potentially differing by sex. Overall, we identified three significant global correlations between iron levels and (i) coronary heart disease, (ii) triglycerides, and (iii) high-density lipoprotein (HDL) cholesterol levels. A total of 194 genomic regions had significant (after correction for multiple testing) local correlations between iron levels and the 11 tested traits. MR analysis revealed two potential causal relationships, between genetically predicted iron levels and (i) total cholesterol or (ii) non-HDL cholesterol. Sex-stratified analyses suggested a potential protective effect of iron levels on Parkinson’s disease risk in females, but not in males. Our results will contribute to a better understanding of the genetic basis underlying iron in cardiovascular and neurological health in aging, and to the eventual identification of new preventive interventions or therapeutic avenues for diseases which affect women and men worldwide.

Few genome-wide association studies (GWAS) analyzing genetic regulation of morphological traits of white blood cells have been reported. We carried out a GWAS of 12 morphological traits in 869 individuals from the general population of Sardinia, Italy. These traits, included measures of cell volume, conductivity and light scatter in four white-cell populations (eosinophils, lymphocytes, monocytes, neutrophils). This analysis yielded seven statistically significant signals, four of which were novel (four novel, PRG2, P2RX3, two of CDK6). Five signals were replicated in the independent INTERVAL cohort of 11 822 individuals. The most interesting signal with large effect size on eosinophil scatter (P-value = 8.33 x 10(-32), beta = -1.651, se = 0.1351) falls within the innate immunity cluster on chromosome 11, and is located in the PRG2 gene. Computational analyses revealed that a rare, Sardinian-specific PRG2:p.Ser148Pro mutation modifies PRG2 amino acid contacts and protein dynamics in a manner that could possibly explain the changes observed in eosinophil morphology. Our discoveries shed light on genetics of morphological traits. For the first time, we describe such large effect size on eosinophils morphology that is relatively frequent in Sardinian population.

Background Genome-wide association studies for glycemic traits have identified hundreds of loci associated with these biomarkers of glucose homeostasis. Despite this success, the challenge remains to link variant associations to genes, and underlying biological pathways. Methods To identify coding variant associations which may pinpoint effector genes at both novel and previously established genome-wide association loci, we performed meta-analyses of exome-array studies for four glycemic traits: glycated hemoglobin (HbA1c, up to 144,060 participants), fasting glucose (FG, up to 129,665 participants), fasting insulin (FI, up to 104,140) and 2hr glucose post-oral glucose challenge (2hGlu, up to 57,878). In addition, we performed network and pathway analyses. Results Single-variant and gene-based association analyses identified coding variant associations at more than 60 genes, which when combined with other datasets may be useful to nominate effector genes. Network and pathway analyses identified pathways related to insulin secretion, zinc transport and fatty acid metabolism. HbA1c associations were strongly enriched in pathways related to blood cell biology. Conclusions Our results provided novel glycemic trait associations and highlighted pathways implicated in glycemic regulation. Exome-array summary statistic results are being made available to the scientific community to enable further discoveries.

Tobacco and alcohol use are heritable behaviours associated with 15% and 5.3% of worldwide deaths, respectively, due largely to broad increased risk for disease and injury 1 – 4 . These substances are used across the globe, yet genome-wide association studies have focused largely on individuals of European ancestries 5 . Here we leveraged global genetic diversity across 3.4 million individuals from four major clines of global ancestry (approximately 21% non-European) to power the discovery and fine-mapping of genomic loci associated with tobacco and alcohol use, to inform function of these loci via ancestry-aware transcriptome-wide association studies, and to evaluate the genetic architecture and predictive power of polygenic risk within and across populations. We found that increases in sample size and genetic diversity improved locus identification and fine-mapping resolution, and that a large majority of the 3,823 associated variants (from 2,143 loci) showed consistent effect sizes across ancestry dimensions. However, polygenic risk scores developed in one ancestry performed poorly in others, highlighting the continued need to increase sample sizes of diverse ancestries to realize any potential benefit of polygenic prediction.

Reproductive longevity is essential for fertility and influences healthy ageing in women1,2, but insights into its underlying biological mechanisms and treatments to preserve it are limited. Here we identify 290 genetic determinants of ovarian ageing, assessed using normal variation in age at natural menopause (ANM) in about 200,000 women of European ancestry. These common alleles were associated with clinical extremes of ANM; women in the top 1% of genetic susceptibility have an equivalent risk of premature ovarian insufficiency to those carrying monogenic FMR1 premutations3. The identified loci implicate a broad range of DNA damage response (DDR) processes and include loss-of-function variants in key DDR-associated genes. Integration with experimental models demonstrates that these DDR processes act across the life-course to shape the ovarian reserve and its rate of depletion. Furthermore, we demonstrate that experimental manipulation of DDR pathways highlighted by human genetics increases fertility and extends reproductive life in mice. Causal inference analyses using the identified genetic variants indicate that extending reproductive life in women improves bone health and reduces risk of type 2 diabetes, but increases the risk of hormone-sensitive cancers. These findings provide insight into the mechanisms that govern ovarian ageing, when they act, and how they might be targeted by therapeutic approaches to extend fertility and prevent disease.

Background: Defective alleles within the PRF1 gene, encoding the pore-forming protein perforin, in combination with environmental factors, cause familial type 2 hemophagocytic lymphohistiocytosis (FHL2), a rare, severe autosomal recessive childhood disorder characterized by massive release of cytokines-cytokine storm. Objective: The aim of this study was to determine the function of hypomorph PRF1:p.A91V g.72360387 G > A on multiple sclerosis (MS) and type 1 diabetes (T1D). Methods: We cross-compare the association data for PRF1:p.A91V mutation derived from GWAS on adult MS and pediatric T1D in Sardinians. The novel association with T1D was replicated in metanalysis in 12,584 cases and 17,692 controls from Sardinia, the United Kingdom, and Scotland. To dissect this mutation function, we searched through the coincident association immunophenotypes in additional set of general population Sardinians. Results: We report that PRF1:p.A91V, is associated with increase of lymphocyte levels, especially within the cytotoxic memory T-cells, at general population level with reduced interleukin 7 receptor expression on these cells. The minor allele increased risk of MS, in 2903 cases and 2880 controls from Sardinia p = 2.06 x 10(-4), odds ratio OR = 1.29, replicating a previous finding, whereas it protects from T1D p = 1.04 x 10(-5), OR = 0.82. Conclusion: Our results indicate opposing contributions of the cytotoxic T-cell compartment to MS and T1D pathogenesis.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Valeria Orrù§, Maristella Steri§, Carlo Sidore§, Michele Marongiu, Valentina Serra, Stefania Olla, Gabriella Sole, Sandra Lai, Mariano Dei, Antonella Mulas, Francesca Virdis, Maria Grazia Piras, Monia Lobina, Mara Marongiu, Maristella Pitzalis, Francesca Deidda, Annalisa Loizedda, Stefano Onano, Magdalena Zoledziewska, Marcella Devoto, Matteo Floris, Mauro Pala, David Schlessinger, Edoardo Fiorillo, Francesco Cucca.

AbstractTo investigate the genetic regulation of platelet (PLT) levels we carried out a whole-genome association analysis in 6,528 Sardinians from the general population of the Lanusei valley. We found 6 variants significantly influencing PLT levels, including a novel rare missense mutation (p.Pro27Ser) in the GP1BB protein that is associated with PLT reduction (P=1.17×10−16). This mutation is rare in the SardiNIA population cohort (frequency of 0.45%), even rarer in the rest of the Sardinian island (frequency of 0.16%), and not reported elsewhere. Notably, GP1BB is involved in Bernard-Soulier syndrome (BSS), a rare autosomal recessive bleeding disorder caused by a defect in the platelet GPIb-IX-V protein complex. Consistently, the 57 identified individuals heterozygous for the p.P27S mutation showed mild thrombocytopenia, morphologically enlarged platelets (P=2.13×10−10), and reduced expression of two GPIb-IX-V-complex components: GPIbα (−26.51%, P=3.66×10−8) and GPIX (−24.69%, P=2.66×10−6). Molecular modeling infers a corresponding reduction in the stability of GP1BB. These observations predict that in homozygosity as well as in individuals carrying specific compound heterozygous configurations, this variant likely causes BSS.

1. Szuber N, Mudireddy M, Nicolosi M, Penna D, Vallapureddy RR, Lasho TL, et al. 3023 Mayo clinic patients with myeloproliferative neoplasms: risk-stratified comparison of survival and outcomes data among disease subgroups. Mayo Clin Proc. 2019;94:599–610. 2. Tefferi A, Mudireddy M, Mannelli F, Begna KH, Patnaik MM, Hanson CA, et al. Blast phase myeloproliferative neoplasm: Mayo-AGIMM study of 410 patients from two separate cohorts. Leukemia. 2018;32:1200–10. 3. Mei M, Aldoss I, Marcucci G, Pullarkat V. Hypomethylating agents in combination with venetoclax for acute myeloid leukemia: Update on clinical trial data and practical considerations for use. Am J Hematol. 2019;94:358–62. 4. Dohner H, Estey E, Grimwade D, Amadori S, Appelbaum FR, Buchner T, et al. Diagnosis and management of AML in adults: 2017 ELN recommendations from an international expert panel. Blood. 2017;129: 424–47. 5. DiNardo CD, Pratz K, Pullarkat V, Jonas BA, Arellano M, Becker PS, et al. Venetoclax combined with decitabine or azacitidine in treatmentnaive, elderly patients with acute myeloid leukemia. Blood. 2019;133:7–17. 6. Morsia E, McCullough K, Joshi M, Cook J, Alkhateeb H, Al-Kali A, et al. Venetoclax and hypomethylating agents in acute myeloid leukemia: Mayo Clinic series on 86 patients. Submitted to Am J Hematol. 2020. https://doi. org/10.1002/ajh.25978

SummaryMetabolic dysregulation in multiple tissues alters glucose homeostasis and influences risk for type 2 diabetes (T2D). To identify pathways and tissues influencing T2D-relevant glycemic traits (fasting glucose [FG], fasting insulin [FI], two-hour glucose [2hGlu] and glycated hemoglobin [HbA1c]), we investigated associations of exome-array variants in up to 144,060 individuals without diabetes of multiple ancestries. Single-variant analyses identified novel associations at 21 coding variants in 18 novel loci, whilst gene-based tests revealed signals at two genes, TF (HbA1c) and G6PC (FG, FI). Pathway and tissue enrichment analyses of trait-associated transcripts confirmed the importance of liver and kidney for FI and pancreatic islets for FG regulation, implicated adipose tissue in FI and the gut in 2hGlu, and suggested a role for the non-endocrine pancreas in glucose homeostasis. Functional studies demonstrated that a novel FG/FI association at the liver-enriched G6PC transcript was driven by multiple rare loss-of-function variants. The FG/HbA1c-associated, islet-specific G6PC2 transcript also contained multiple rare functional variants, including two alleles within the same codon with divergent effects on glucose levels. Our findings highlight the value of integrating genomic and functional data to maximize biological inference.Highlights23 novel coding variant associations (single-point and gene-based) for glycemic traits51 effector transcripts highlighted different pathway/tissue signatures for each traitThe exocrine pancreas and gut influence fasting and 2h glucose, respectivelyMultiple variants in liver-enriched G6PC and islet-specific G6PC2 influence glycemia

Tobacco and alcohol use are leading causes of mortality that influence risk for many complex diseases and disorders1. They are heritable2,3 and etiologically related4,5 behaviors that have been resistant to gene discovery efforts6–11. In sample sizes up to 1.2 million individuals, we discovered 566 genetic variants in 406 loci associated with multiple stages of tobacco use (initiation, cessation, and heaviness) as well as alcohol use, with 150 loci evidencing pleiotropic association. Smoking phenotypes were positively genetically correlated with many health conditions, whereas alcohol use was negatively correlated with these conditions, such that increased genetic risk for alcohol use is associated with lower disease risk. We report evidence for the involvement of many systems in tobacco and alcohol use, including genes involved in nicotinic, dopaminergic, and glutamatergic neurotransmission. The results provide a solid starting point to evaluate the effects of these loci in model organisms and more precise substance use measures. Association studies of up to 1.2 million individuals identify 566 genetic variants in 406 loci associated with tobacco use and addiction (initiation, cessation, and heaviness) as well as alcohol use, with 150 loci showing pleiotropic association.

European populations display low genetic differentiation as the result of long-term blending of their ancient founding ancestries. However, it is unclear how the combination of ancient ancestries related to early foragers, Neolithic farmers, and Bronze Age nomadic pastoralists can explain the distribution of genetic variation across Europe. Populations in natural crossroads like the Italian peninsula are expected to recapitulate the continental diversity, but have been systematically understudied. Here, we characterize the ancestry profiles of Italian populations using a genome-wide dataset representative of modern and ancient samples from across Italy, Europe, and the rest of the world. Italian genomes capture several ancient signatures, including a non-steppe contribution derived ultimately from the Caucasus. Differences in ancestry composition, as the result of migration and admixture, have generated in Italy the largest degree of population structure detected so far in the continent, as well as shaping the amount of Neanderthal DNA in modern-day populations.