Gut microbiota analyses of inflammatory bowel diseases from a representative Saudi population.

BACKGROUND: Crohn's diseases and ulcerative colitis, both of which are chronic immune-mediated disorders of the gastrointestinal tract are major contributors to the overarching Inflammatory bowel diseases. It has become increasingly evident that the pathological processes of IBDs results from interactions between genetic and environmental factors, which can skew immune responses against normal intestinal flora. METHODS: The aim of this study is to assess and analyze the taxa diversity and relative abundances in CD and UC in the Saudi population. We utilized a sequencing strategy that targets all variable regions in the 16 S rRNA gene using the Swift Amplicon 16 S rRNA Panel on Illumina NovaSeq 6000. RESULTS: The composition of stool 16 S rRNA was analyzed from 219 patients with inflammatory bowel disease and from 124 healthy controls. We quantified the abundance of microbial communities to examine any significant differences between subpopulations of samples. At the genus level, two genera in particular, Veillonella and Lachnoclostridium showed significant association with CD versus controls. There were significant differences between subjects with CD versus UC, with the top differential genera spanning Akkermansia, Harryflintia, Maegamonas and Phascolarctobacterium. Furthermore, statistically significant taxa diversity in microbiome composition was observed within the UC and CD groups. CONCLUSIONS: In conclusion we have shown that there are significant differences in gut microbiota between UC, CD and controls in a Saudi Arabian inflammatory bowel disease cohort. This reinforces the need for further studies in large populations that are ethnically and geographically diverse. In addition, our results show the potential to develop classifiers that may have add additional richness of context to clinical diagnosis of UC and CD with larger inflammatory bowel disease cohorts.

Unsupervised mRNA-seq classification of heart transplant endomyocardial biopsies.

BACKGROUND: Endomyocardial biopsy (EMB) is currently considered the gold standard for diagnosing cardiac allograft rejection. However, significant limitations related to histological interpretation variability are well-recognized. We sought to develop a methodology to evaluate EMB solely based on gene expression, without relying on histology interpretation. METHODS: Sixty-four EMBs were obtained from 47 post-heart transplant recipients, who were evaluated for allograft rejection. EMBs were subjected to mRNA sequencing, in which an unsupervised classification algorithm was used to identify the molecular signatures that best classified the EMBs. Cytokine and natriuretic peptide peripheral blood profiling was also performed. Subsequently, we performed gene network analysis to identify the gene modules and gene ontology to understand their biological relevance. We correlated our findings with the unsupervised and histological classifications. RESULTS: Our algorithm classifies EMBs into three categories based solely on clusters of gene expression: unsupervised classes 1, 2, and 3. Unsupervised and histological classifications were closely related, with stronger gene module-phenotype correlations for the unsupervised classes. Gene ontology enrichment analysis revealed processes impacting on the regulation of cardiac and mitochondrial function, immune response, and tissue injury response. Significant levels of cytokines and natriuretic peptides were detected following the unsupervised classification. CONCLUSION: We have developed an unsupervised algorithm that classifies EMBs into three distinct categories, without relying on histology interpretation. These categories were highly correlated with mitochondrial, immune, and tissue injury response. Significant cytokine and natriuretic peptide levels were detected within the unsupervised classification. If further validated, the unsupervised classification could offer a more objective EMB evaluation.

Inference of Causal Relationships Between Genetic Risk Factors for Cardiometabolic Phenotypes and Female-Specific Health Conditions.

Background Cardiometabolic diseases are highly comorbid, but their relationship with female-specific or overwhelmingly female-predominant health conditions (breast cancer, endometriosis, pregnancy complications) is understudied. This study aimed to estimate the cross-trait genetic overlap and influence of genetic burden of cardiometabolic traits on health conditions unique to women. Methods and Results Using electronic health record data from 71 008 ancestrally diverse women, we examined relationships between 23 obstetrical/gynecological conditions and 4 cardiometabolic phenotypes (body mass index, coronary artery disease, type 2 diabetes, and hypertension) by performing 4 analyses: (1) cross-trait genetic correlation analyses to compare genetic architecture, (2) polygenic risk score-based association tests to characterize shared genetic effects on disease risk, (3) Mendelian randomization for significant associations to assess cross-trait causal relationships, and (4) chronology analyses to visualize the timeline of events unique to groups of women with high and low genetic burden for cardiometabolic traits and highlight the disease prevalence in risk groups by age. We observed 27 significant associations between cardiometabolic polygenic scores and obstetrical/gynecological conditions (body mass index and endometrial cancer, body mass index and polycystic ovarian syndrome, type 2 diabetes and gestational diabetes, type 2 diabetes and polycystic ovarian syndrome). Mendelian randomization analysis provided additional evidence of independent causal effects. We also identified an inverse association between coronary artery disease and breast cancer. High cardiometabolic polygenic scores were associated with early development of polycystic ovarian syndrome and gestational hypertension. Conclusions We conclude that polygenic susceptibility to cardiometabolic traits is associated with elevated risk of certain female-specific health conditions.

Whole transcriptome profiling of prospective endomyocardial biopsies reveals prognostic and diagnostic signatures of cardiac allograft rejection.

BACKGROUND: Heart transplantation provides a significant improvement in survival and quality of life for patients with end-stage heart disease, however many recipients experience different levels of graft rejection that can be associated with significant morbidities and mortality. Current clinical standard-of-care for the evaluation of heart transplant acute rejection (AR) consists of routine endomyocardial biopsy (EMB) followed by visual assessment by histopathology for immune infiltration and cardiomyocyte damage. We assessed whether the sensitivity and/or specificity of this process could be improved upon by adding RNA sequencing (RNA-seq) of EMBs coupled with histopathological interpretation. METHODS: Up to 6 standard-of-care, or for-cause EMBs, were collected from 26 heart transplant recipients from the prospective observational Clinical Trials of Transplantation (CTOT)-03 study, during the first 12-months post-transplant and subjected to RNA-seq (n = 125 EMBs total). Differential expression and random-forest-based machine learning were applied to develop signatures for classification and prognostication. RESULTS: Leveraging the unique longitudinal nature of this study, we show that transcriptional hallmarks for significant rejection events occur months before the actual event and are not visible using traditional histopathology. Using this information, we identified a prognostic signature for 0R/1R biopsies that with 90% accuracy can predict whether the next biopsy will be 2R/3R. CONCLUSIONS: RNA-seq-based molecular characterization of EMBs shows significant promise for the early detection of cardiac allograft rejection.

Design and Methods of the Validating Injury to the Renal Transplant Using Urinary Signatures (VIRTUUS) Study in Children.

Lack of noninvasive diagnostic and prognostic biomarkers to reliably detect early allograft injury poses a major hindrance to long-term allograft survival in pediatric kidney transplant recipients. METHODS: Validating Injury to the Renal Transplant Using Urinary Signatures Children's Study, a North American multicenter prospective cohort study of pediatric kidney transplant recipients, aims to validate urinary cell mRNA and metabolite profiles that were diagnostic and prognostic of acute cellular rejection (ACR) and BK virus nephropathy (BKVN) in adult kidney transplant recipients in Clinical Trials in Organ Transplantation-4. Specifically, we are investigating: (1) whether a urinary cell mRNA 3-gene signature (18S-normalized CD3ε, CXCL10 mRNA, and 18S ribosomal RNA) discriminates biopsies with versus without ACR, (2) whether a combined metabolite profile with the 3-gene signature increases sensitivity and specificity of diagnosis and prognostication of ACR, and (3) whether BKV-VP1 mRNA levels in urinary cells are diagnostic of BKVN and prognostic for allograft failure. RESULTS: To date, 204 subjects are enrolled, with 1405 urine samples, including 144 biopsy-associated samples. Among 424 urine samples processed for mRNA, the median A260:280 ratio (RNA purity) was 1.91, comparable with Clinical Trials in Organ Transplantation-4 (median 1.82). The quality control failure rate was 10%. Preliminary results from urine supernatant showed that our metabolomics platform successfully captured a broad array of metabolites. Clustering of pool samples and overlay of samples from various batches demonstrated platform robustness. No study site effect was noted. CONCLUSIONS: Multicenter efforts to ascertain urinary biomarkers in pediatric kidney transplant recipients are feasible with high-quality control. Further study will inform whether these signatures are discriminatory and predictive for rejection and infection.

Early detection of SARS-CoV-2 and other infections in solid organ transplant recipients and household members using wearable devices.

The increasing global prevalence of SARS-CoV-2 and the resulting COVID-19 disease pandemic pose significant concerns for clinical management of solid organ transplant recipients (SOTR). Wearable devices that can measure physiologic changes in biometrics including heart rate, heart rate variability, body temperature, respiratory, activity (such as steps taken per day) and sleep patterns, and blood oxygen saturation show utility for the early detection of infection before clinical presentation of symptoms. Recent algorithms developed using preliminary wearable datasets show that SARS-CoV-2 is detectable before clinical symptoms in >80% of adults. Early detection of SARS-CoV-2, influenza, and other pathogens in SOTR, and their household members, could facilitate early interventions such as self-isolation and early clinical management of relevant infection(s). Ongoing studies testing the utility of wearable devices such as smartwatches for early detection of SARS-CoV-2 and other infections in the general population are reviewed here, along with the practical challenges to implementing these processes at scale in pediatric and adult SOTR, and their household members. The resources and logistics, including transplant-specific analyses pipelines to account for confounders such as polypharmacy and comorbidities, required in studies of pediatric and adult SOTR for the robust early detection of SARS-CoV-2, and other infections are also reviewed.

Genomics and Liver Transplantation: Genomic Biomarkers for the Diagnosis of Acute Cellular Rejection.

Acute cellular rejection (ACR) is a common complication in liver transplantation recipients (LTRs), especially within the first 12 months, and it is associated with increased morbidity and mortality. Although abnormalities in standard liver biochemistries may raise the clinical suspicion for ACR, it lacks specificity, and invasive liver biopsies, which are associated with numerous risks, are required for definitive diagnoses. Biomarker discovery for minimally invasive tools for diagnosis and prognostication of ACR after liver transplantation (LT) has become a rapidly evolving field of research with a recent shift in focus to omics-based biomarker discovery. Although none are yet ready to replace the standard of care, there are several promising minimally invasive, blood-derived biomarkers that are under intensive research for the diagnosis of ACR in LTRs. These omics-based biomarkers, encompassing DNA, RNA, proteins, and metabolites, hold tremendous potential. Some are likely to become integrated into ACR diagnostic algorithms to assist clinical decision making with a high degree of accuracy that is cost-effective and reduces or even obviates the need for an invasive liver biopsy.

Polygenic risk score of non-melanoma skin cancer predicts post-transplant skin cancer across multiple organ types.

Polygenic risk scores (PRSs) calculated from genome-wide association studies (GWASs) of non-melanoma skin cancer (NMSC) in a general, non-transplant setting have recently been shown to predict risk of and time to post-renal transplant skin cancer. In this study, we set out to test these findings in a cohort of heart, lung, and liver transplant patients to see whether these scores could be applied across different organ transplant types. Using the PRS from Stapleton et al (2018), PRS was calculated for each sample across a European ancestry heart, lung, and liver transplant cohorts (n = 523) and tested as predictor of time to NMSC post-transplant. The top PRS, squamous cell carcinoma (SCC) pT1 x 10-5 , (n SNPs = 1953), SCC pT1 x 10-6 , and SCC pT1 x 10-6 (n SNPs = 1061) were significantly predictive in the time to NMSC, SCC, and basal cell carcinoma (BCC) analysis across organ (P = .006, .02, and .02, respectively). We observed here a similar direction of effect and effect size [NMSC HR = 1.31(1.08-1.59)] to that in the original discovery study with increased polygenic burden leading to a faster time to developing NMSC. In summary, we found that PRS of NMSC calculated from GWAS of NMSC in non-transplant populations independently replicated in this cohort of heart, lung, and liver transplant.

Rare copy number variants in over 100,000 European ancestry subjects reveal multiple disease associations.

Copy number variants (CNVs) are suggested to have a widespread impact on the human genome and phenotypes. To understand the role of CNVs across human diseases, we examine the CNV genomic landscape of 100,028 unrelated individuals of European ancestry, using SNP and CGH array datasets. We observe an average CNV burden of ~650 kb, identifying a total of 11,314 deletion, 5625 duplication, and 2746 homozygous deletion CNV regions (CNVRs). In all, 13.7% are unreported, 58.6% overlap with at least one gene, and 32.8% interrupt coding exons. These CNVRs are significantly more likely to overlap OMIM genes (2.94-fold), GWAS loci (1.52-fold), and non-coding RNAs (1.44-fold), compared with random distribution (P < 1 × 10-3). We uncover CNV associations with four major disease categories, including autoimmune, cardio-metabolic, oncologic, and neurological/psychiatric diseases, and identify several drug-repurposing opportunities. Our results demonstrate robust frequency definition for large-scale rare variant association studies, identify CNVs associated with major disease categories, and illustrate the pleiotropic impact of CNVs in human disease.

Current and Future Approaches for Monitoring Responses to Anti-complement Therapeutics.

Aberrations in complement system functions have been identified as either direct or indirect pathophysiological mechanisms in many diseases and pathological conditions, such as infections, autoimmune diseases, inflammation, malignancies, and allogeneic transplantation. Currently available techniques to study complement include quantification of (a) individual complement components, (b) complement activation products, and (c) molecular mechanisms/function. An emerging area of major interest in translational studies aims to study and monitor patients on complement regulatory drugs for efficacy as well as adverse events. This area is progressing rapidly with several anti-complement therapeutics under development, in clinical trials, or already in clinical use. In this review, we summarized the appropriate indications, techniques, and interpretations of basic complement analyses, exemplified by a number of clinical disorders.

Genome-Wide Study Updates in the International Genetics and Translational Research in Transplantation Network (iGeneTRAiN).

The prevalence of end-stage renal disease (ESRD) and the number of kidney transplants performed continues to rise every year, straining the procurement of deceased and living kidney allografts and health systems. Genome-wide genotyping and sequencing of diseased populations have uncovered genetic contributors in substantial proportions of ESRD patients. A number of these discoveries are beginning to be utilized in risk stratification and clinical management of patients. Specifically, genetics can provide insight into the primary cause of chronic kidney disease (CKD), the risk of progression to ESRD, and post-transplant outcomes, including various forms of allograft rejection. The International Genetics & Translational Research in Transplantation Network (iGeneTRAiN), is a multi-site consortium that encompasses >45 genetic studies with genome-wide genotyping from over 51,000 transplant samples, including genome-wide data from >30 kidney transplant cohorts (n = 28,015). iGeneTRAiN is statistically powered to capture both rare and common genetic contributions to ESRD and post-transplant outcomes. The primary cause of ESRD is often difficult to ascertain, especially where formal biopsy diagnosis is not performed, and is unavailable in ∼2% to >20% of kidney transplant recipients in iGeneTRAiN studies. We overview our current copy number variant (CNV) screening approaches from genome-wide genotyping datasets in iGeneTRAiN, in attempts to discover and validate genetic contributors to CKD and ESRD. Greater aggregation and analyses of well phenotyped patients with genome-wide datasets will undoubtedly yield insights into the underlying pathophysiological mechanisms of CKD, leading the way to improved diagnostic precision in nephrology.

Exome sequencing of Saudi Arabian patients with ADPKD.

Purpose: Autosomal dominant polycystic kidney disease (ADPKD) is characterized by progressive development of kidney cysts and enlargement and dysfunction of the kidneys. The Consortium of Radiologic Imaging Studies of the Polycystic Kidney Disease (CRISP) cohort revealed that 89.1% had either a PKD1 or PKD2 mutation. Of the CRISP patients with a genetic cause detected, mutations in PKD1 accounted for 85%, while mutations in the PKD2 accounted for the remaining 15%. Here, we report exome sequencing of 16 Saudi patients diagnosed with ADPKD and 16 ethnically matched controls. Methods: Exome sequencing was performed using combinatorial probe-anchor synthesis and improved DNA Nanoballs technology on BGISEQ-500 sequencers (BGI, China) using the BGI Exome V4 (59 Mb) Kit. Identified variants were validated with Sanger sequencing. Results: With the exception of GC-rich exon 1, we obtained excellent coverage of PKD1 (mean read depth = 88) including both duplicated and non-duplicated regions. Of nine patients with typical ADPKD presentations (bilateral symmetrical kidney involvement, positive family history, concordant imaging, and kidney function), four had protein truncating PKD1 mutations, one had a PKD1 missense mutation, and one had a PKD2 mutation. These variants have not been previously observed in the Saudi population. In seven clinically diagnosed ADPKD cases but with atypical features, no PKD1 or PKD2 mutations were identified, but rare predicted pathogenic heterozygous variants were found in cystogenic candidate genes including PKHD1, PKD1L3, EGF, CFTR, and TSC2. Conclusions: Mutations in PKD1 and PKD2 are the most common cause of ADPKD in Saudi patients with typical ADPKD. Abbreviations: ADPKD: Autosomal dominant polycystic kidney disease; CFTR: Cystic fibrosis transmembrane conductance regulator; EGF: Epidermal growth factor; MCIC: Mayo Clinic Imaging Classification; PKD: Polycystic kidney disease; TSC2: Tuberous sclerosis complex 2.

Contribution of non-HLA incompatibility between donor and recipient to kidney allograft survival: genome-wide analysis in a prospective cohort.

BACKGROUND: The introduction of HLA matching of donors and recipients was a breakthrough in kidney transplantation. However, half of all transplanted kidneys still fail within 15 years after transplantation. Epidemiological data suggest a fundamental role of non-HLA alloimmunity. METHODS: We genotyped 477 pairs of deceased donors and first kidney transplant recipients with stable graft function at three months that were transplanted between Dec 1, 2005, and April 30, 2015. Genome-wide genetic mismatches in non-synonymous single nucleotide polymorphisms (nsSNPs) were calculated to identify incompatibilities in transmembrane and secreted proteins. We estimated the association between nsSNP mismatch and graft loss in a Cox proportional hazard model, adjusting for HLA mismatch and clinical covariates. Customised peptide arrays were generated to screen for antibodies against genotype-derived mismatched epitopes in 25 patients with biopsy-confirmed chronic antibody-mediated rejection. FINDINGS: 59 268 nsSNPs affecting a transmembrane or secreted protein were analysed. The median number of nsSNP mismatches in immune-accessible transmembrane and secreted proteins between donors and recipients was 1892 (IQR 1850-1936). The degree of nsSNP mismatch was independently associated with graft loss in a multivariable model adjusted for HLA eplet mismatch (HLA-A, HLA-B, HLA-C, HLA-DP, HLA-DQ, and HLA-DR). Each increase by a unit of one IQR had an HR of 1·68 (95% CI 1·17-2·41, p=0·005). 5-year death censored graft survival was 98% in the quartile with the lowest mismatch, 91% in the second quartile, 89% in the third quartile, and 82% in the highest quartile (p=0·003, log-rank test). Customised peptide arrays verified a donor-specific alloimmune response to genetically predicted mismatched epitopes. INTERPRETATION: Genetic mismatch of non-HLA haplotypes coding for transmembrane or secreted proteins is associated with an increased risk of functional graft loss independently of HLA incompatibility. As in HLA alloimmunity, donor-specific alloantibodies can be identified against genotype derived non-HLA epitopes. FUNDING: Austrian Science Fund, WWTF (Vienna Science and Technology Fund), and Ministry of Health of the Czech Republic.

Polygenic risk score as a determinant of risk of non-melanoma skin cancer in a European-descent renal transplant cohort.

Renal transplant recipients have an increased risk of non-melanoma skin cancer (NMSC) compared to in the general population. Here, we show polygenic risk scores (PRS) calculated from genome-wide association studies (GWAS) of NMSC in a general, nontransplant setting, can predict risk of, and time to posttransplant skin cancer. Genetic variants, reaching predefined P-value thresholds were chosen from published squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) nontransplant GWAS. Using these GWAS, BCC and SCC PRS were calculated for each sample across three European ancestry renal transplant cohorts (n = 889) and tested as predictors of case:control status and time to NMSC posttransplant. BCC PRS calculated at P-value threshold 1 × 10-5 was the most significant predictor of case:control status of NMSC posttransplant (OR = 1.61; adjusted P = .0022; AUC [full model adjusted for clinical predictors and PRS] = 0.81). SCC PRS at P-value threshold 1 × 10-5 was the most significant predictor of time to posttransplant NMSC (adjusted P = 9.39 × 10-7 ; HR = 1.41, concordance [full model] = 0.74). PRS of nontransplant NMSC is predictive of case:control status and time to NMSC posttransplant. These results are relevant to how genomics can risk stratify patients to help develop personalized treatment regimens.

Assessing known chronic kidney disease associated genetic variants in Saudi Arabian populations.

BACKGROUND: Genome wide association studies of patients with European descent have identified common variants associated with risk of reduced estimated glomerular filtration rate (eGFR). A panel of eight variants were selected to evaluate their association and prevalence in a Saudi Arabian patient cohort with chronic kidney disease (CKD). METHODS: Eight genetic variants in four genes (SHROOM3, MYH9, SLC7A9, and CST3) were genotyped in 160 CKD patients and 189 ethnicity-matched healthy controls. Genetic variants were tested for association with the development of CKD (eGFR < 60 ml/min/1.73m2) and effects were compared with results obtained from 133,413 participants in the CKD genetics consortium. Multivariable regression was used to evaluate the role of these eight variants in improving prediction of CKD development. RESULTS: All eight variants were present in Saudi populations with minor allele frequency ranging from 16 to 46%. The risk variant in all four genes demonstrated the same direction of effect as observed in European populations. One variant, rs4821480, in MYH9 was significantly associated with increased risk of development of CKD (OR = 1.69, 95% CI 1.22-2.36, P = 0.002), but the additional variants were not statistically significant given our modest sample size. CONCLUSIONS: CKD risk variants identified in European populations are present in Saudis. We did not find evidence to suggest heterogeneity of effect size compared to previously published estimates in European populations. Multivariable logistic regression analysis showed a statistically significant improvement in predicting the CKD using models with either FGF23 and vitamin D or FGF23, vitamin D level, and MYH9 genotypes (AUC = 0.93, 95% CI 0.90-0.95, P <  0.0001).

NPHP1 (Nephrocystin-1) Gene Deletions Cause Adult-Onset ESRD.

Background Nephronophthisis (NPH) is the most prevalent genetic cause for ESRD in children. However, little is known about the prevalence of NPH in adult-onset ESRD. Homozygous full gene deletions of the NPHP1 gene encoding nephrocystin-1 are a prominent cause of NPH. We determined the prevalence of NPH in adults by assessing homozygous NPHP1 full gene deletions in adult-onset ESRD.Methods Adult renal transplant recipients from five cohorts of the International Genetics and Translational Research in Transplantation Network (iGeneTRAiN) underwent single-nucleotide polymorphism genotyping. After quality control, we determined autosomal copy number variants (such as deletions) on the basis of median log2 ratios and B-allele frequency patterns. The findings were independently validated in one cohort. Patients were included in the analysis if they had adult-onset ESRD, defined as start of RRT at ≥18 years old.Results We included 5606 patients with adult-onset ESRD; 26 (0.5%) showed homozygous NPHP1 deletions. No donor controls showed homozygosity for this deletion. Median age at ESRD onset was 30 (range, 18-61) years old for patients with NPH, with 54% of patients age ≥30 years old. Notably, only three (12%) patients were phenotypically classified as having NPH, whereas most patients were defined as having CKD with unknown etiology (n=11; 42%).Conclusions Considering that other mutation types in NPHP1 or mutations in other NPH-causing genes were not analyzed, NPH is a relatively frequent monogenic cause of adult-onset ESRD. Because 88% of patients had not been clinically diagnosed with NPH, wider application of genetic testing in adult-onset ESRD may be warranted.

Genetic predisposition to elevated levels of C-reactive protein is associated with a decreased risk for preeclampsia.

OBJECTIVE: To examine the association between genetic predisposition to elevated C-reactive protein (CRP)and risk for preeclampsia using validated genetic loci for C-reactive protein. METHODS: Preeclampsia cases (n = 177) and normotensive controls (n = 116) were selected from live birth certificates to nulliparous Iowa women during the period August 2002-May 2005. Disease status was verified by the medical chart review. Genetic predisposition to CRP was estimated by a genetic risk score on the basis of established loci for CRP levels. Logistic regression analyses were used to evaluate the relationships between the genotype score and preeclampsia. Replication analyses were performed in an independent, US population of preeclampsia cases (n = 516) and controls (n = 1,097) of European ancestry. RESULTS: The genetic risk score (GRS) related to higher levels of CRP demonstrated a significantly decreased risk of preeclampsia (OR 0.89, 95% CI 0.82-0.96). When the GRS was analyzed by quartile, an inverse linear trend was observed (p = 0.0006). The results were similar after adjustments for the body mass index (BMI), smoking, and leisure-time physical activity. In the independent replication population, the association with the CRP GRS was also marginally significant (OR 0.97, 95% CI 0.92, 1.02). Meta-analysis of the two studies was statistically significant (OR 0.95, 95% CI 0.90, 0.99). CONCLUSION: Our data suggest an inverse, counterintuitive association between the genetic predisposition to elevated levels of CRP and a decreased risk of preeclampsia. This suggests that the blood CRP level is a marker of preeclampsia, but it does not appear to be a factor on the causal pathway.

An ectopically expressed serum miRNA signature is prognostic, diagnostic, and biologically related to liver allograft rejection.

The ability to noninvasively diagnose acute cellular rejection (ACR) with high specificity and sensitivity would significantly advance personalized liver transplant recipient care and management of immunosuppression. We performed microRNA (miRNA) profiling in 318 serum samples from 69 liver transplant recipients enrolled in the Immune Tolerance Network immunosuppression withdrawal (ITN030ST) and Clinical Trials in Organ Transplantation (CTOT-03) studies. We quantified serum miRNA at clinically indicated and/or protocol biopsy events (n = 130). The trajectory of ACR diagnostic miRNAs during immunosuppression withdrawal were also evaluated in sera taken at predetermined intervals during immunosuppression minimization before and at clinically indicated liver biopsy (n = 119). Levels of 31 miRNAs were significantly associated with ACR diagnosis with two miRNAs differentiating ACR from non-ACR (area under the receiver operating characteristic curve = 90%, 95% confidence interval = 82%-96%) and predicted ACR events up to 40 days before biopsy-proven rejection. The most differentially expressed miRNAs were low or absent in the blood of healthy individuals but highly expressed in liver tissue, indicating an ectopic origin from the liver allograft. Pathway analyses of rejection-associated miRNAs and their target messenger RNAs (mRNAs) showed induction of proinflammatory and cell death-related pathways. Integration of differentially expressed serum miRNA with concordant liver biopsy mRNA demonstrates interaction between molecules with a known role in transplant rejection. CONCLUSION: Distinct miRNA levels profiled from sera at the time of clinical allograft dysfunction can be used to noninvasively diagnose ACR. Predictive trajectories of the same profile during supervised immunosuppression minimization diagnosed rejection up to 40 days prior to clinical expression. The rejection-associated miRNAs in sera appear to be ectopically expressed liver and specific immune cell miRNAs that are biologically related, and the consequences of immune-mediated damage to the allograft. (Hepatology 2017;65:269-280).

CSF1R mosaicism in a family with hereditary diffuse leukoencephalopathy with spheroids.

Mutations in the colony stimulating factor 1 receptor (CSF1R) have recently been discovered as causal for hereditary diffuse leukoencephalopathy with axonal spheroids. We identified a novel, heterozygous missense mutation in CSF1R [c.1990G > A p.(E664K)] by exome sequencing in five members of a family with hereditary diffuse leukoencephalopathy with axonal spheroids. Three affected siblings had characteristic white matter abnormalities and presented with progressive neurological decline. In the fourth affected sibling, early progression halted after allogeneic haematopoietic stem cell transplantation from a related donor. Blood spot DNA from this subject displayed chimerism in CSF1R acquired after haematopoietic stem cell transplantation. Interestingly, both parents were unaffected but the mother's blood and saliva were mosaic for the CSF1R mutation. Our findings suggest that expression of wild-type CSF1R in some cells, whether achieved by mosaicism or chimerism, may confer benefit in hereditary diffuse leukoencephalopathy with axonal spheroids and suggest that haematopoietic stem cell transplantation might have a therapeutic role for this disorder.

Gene-centric approach identifies new and known loci for FVIII activity and VWF antigen levels in European Americans and African Americans.

Coagulation factor VIII and von Willebrand factor (VWF) are key proteins in procoagulant activation. Higher FVIII coagulant activity (FVIII :C) and VWF antigen (VWF :Ag) are risk factors for cardiovascular disease and venous thromboembolism. Beyond associations with ABO blood group, genetic determinants of FVIII and VWF are not well understood, especially in non European-American populations. We performed a genetic association study of FVIII :C and VWF:Ag that assessed 50,000 gene-centric single nucleotide polymorphisms (SNPs) in 18,556 European Americans (EAs) and 5,047 African Americans (AAs) from five population-based cohorts. Previously unreported associations for FVIII :C were identified in both AAs and EAs with KNG1 (most significantly associated SNP rs710446, Ile581Thr, Ile581Thr, P = 5.10 × 10(-7) in EAs and P = 3.88 × 10(-3) in AAs) and VWF rs7962217 (Gly2705Arg,P = 6.30 × 10(-9) in EAs and P = 2.98 × 10(-2) in AAs. Significant associations for FVIII :C were also observed with F8/TMLHE region SNP rs12557310 in EAs (P = 8.02 × 10(-10) ), with VWF rs1800380 in AAs (P = 5.62 × 10(-11) ), and with MAT1A rs2236568 in AAs (P51.69 × 10(-6) ). We replicated previously reported associations of FVIII :C and VWF :Ag with the ABO blood group, VWF rs1063856(Thr789Ala), rs216321 (Ala852Gln), and VWF rs2229446 (Arg2185Gln). Findings from this study expand our understanding of genetic influences for FVIII :C and VWF :Ag in both EAs and AAs.