Oleg Borisov

Primary hemophagocytic lymphohistiocytosis (HLH) is mainly caused by biallelic variants in genes disrupting cytotoxic natural killer (NK) cell and T-cell function (PRF1, UNC13D, STX11, STXBP2, RAB27A, and LYST). A “pathway defect accumulation” model proposes that heterozygous variants in multiple familial hemophagocytic lymphohistiocytosis (FHL) genes (digenic or multigenic inheritance) may increase susceptibility, but its significance remains debated. We assessed the prevalence and clinical relevance of digenic/multigenic FHL genotypes in a German FHL cohort (1987-2023) and the UK Biobank (UKB; 469 589 participants). We analyzed (1) variants classified as disease mutations in the Human Gene Mutation database (HGMD); (2) common variants such as PRF1 p.Ala91Val and p.Asn252Ser; and (3) additional variants previously reported in digenic HLH and explored phenotypic associations using codes of the International Classification of Diseases, 10th Revision for possible HLH-related conditions. In the German cohort, among 635 individuals sequenced for >1 FHL gene, no symptomatic patient with abnormal NK/cytotoxic T-lymphocyte degranulation carried digenic/multigenic heterozygous variants. In UKB, 575 individuals carried digenic FHL genotypes (0.1% prevalence), without enrichment for HLH-associated phenotypes (odds ratio, 0.95; P = 1). Four individuals carried trigenic genotypes; none had HLH-related diagnoses. Several HGMD-labeled pathogenic variants were observed biallelically in asymptomatic adults, suggesting potential misclassification. Including PRF1 p.Ala91Val and p.Asn252Ser increased digenic variant carriers to 2590 but did not cause phenotype enrichment. Digenic heterozygous FHL variants are relatively common in the general population but do not confer increased FHL risk. Many reported pathogenic FHL variants may be benign. These findings argue against classifying multigenic heterozygous carriers as at risk and support integrating population data into variant interpretation.

Zinc is essential for many physiological processes and its deficiency is highly prevalent worldwide. Its complex homeostasis involves membrane transporters from the SLC39/ZIP and SLC30/ZnT protein families. We conducted a genome-wide association study (GWAS) meta-analysis of urinary zinc levels in three European-ancestry cohorts (N = 10,113), followed by in silico and in vivo studies to elucidate their underlying public health and physiological relevance. We identified eleven genome-wide significant signals with six mapping to SLC39/ZIP and SLC30/ZnT gene regions. The lead signal (rs3008217C>G, p = 2.42E-110) in the SLC30A2 gene region which explained 6.1% of urinary zinc variation strongly colocalized with its expression in kidney tubules. Low phenotypic and genetic correlations between plasma and urinary zinc levels indicated distinct genetic regulation. High urinary zinc correlated with an unfavorable cardiometabolic profile, and Mendelian randomization analyses suggested causal roles for diabetes increasing urinary zinc levels, and elevated urinary zinc increasing stroke risk. Analyzing country-level allele frequencies and zinc deficiency prevalences revealed a 3-fold higher genetic zinc excretion risk in sub-Saharan Africa compared to Europe, significantly correlating with nutritional zinc deficiency prevalence. Although mutations in SLC30A2 are linked to insufficient zinc in human milk, we found no association with common variants using data generated from 387 mothers. Mice experiments showed that dietary zinc deficiency decreased urinary but not plasma zinc levels, and upregulated kidney Slc30a2 expression. This first GWAS on urinary zinc highlights the involvement of zinc transporters in its genetic regulation, as well as its role as a non-invasive biomarker for cardiometabolic diseases.

Genetic screening for severe congenital immunohematological diseases offers potential for early intervention, particularly through preemptive allogeneic hematopoietic stem cell transplantation (HSCT). However, the clinical value of such screening depends on precise prognostic predictions based on genotype-phenotype correlations and/or functional confirmation. We investigated familial hemophagocytic lymphohistiocytosis type 2 (FHL2), caused by PRF1 variants. Specifically, we evaluated the clinical significance of the frequent PRF1 A91V variant, if present in trans with a predicted loss-of-function (pLOF) PRF1 variant, defined as “disease mutation” listed in the Human Gene Mutation Database. We combined clinical and functional data from our hemophagocytic lymphohistiocytosis (HLH)–network registry with UK Biobank data to evaluate disease penetrance and clinical outcomes. Among 52 individuals with A91V/pLOF genotype in the registry, 39 (72%) showed FHL2-related manifestations with mean onset at 20 years. Four patients had recurrent disease, 15 received transplantation, and 14 died. Among 14 individuals with A91V/pLOF genotype identified by family screening (mean age, 29 years), however, only 1 was symptomatic. Moreover, among 21 A91V/pLOF carriers identified in 200 000 UK Biobank participants, 12 with genotypes identical to symptomatic registry patients, none had developed HLH by age 73 years. Premature stop pLOF alleles appeared more penetrant than missense variants, but functional data including perforin expression or cytotoxicity failed to predict disease manifestation. Our combined registry and population-based approach reveals significant variability in disease penetrance and severity among PRF1 A91V/pLOF carriers, with no clear association between genotype, functional data, and clinical outcomes. This complexity illustrates the challenges of genetic screening and highlights the need for careful clinical decision-making regarding preemptive HSCT in asymptomatic carriers.

Genetic studies of the metabolome can uncover enzymatic and transport processes shaping human metabolism. Using rare variant aggregation testing based on whole-exome sequencing data to detect genes associated with levels of 1,294 plasma and 1,396 urine metabolites, we discovered 235 gene–metabolite associations, many previously unreported. Complementary approaches (genetic, computational (in silico gene knockouts in whole-body models of human metabolism) and one experimental proof of principle) provided orthogonal evidence that studies of rare, damaging variants in the heterozygous state permit inferences concordant with those from inborn errors of metabolism. Allelic series of functional variants in transporters responsible for transcellular sulfate reabsorption (SLC13A1, SLC26A1) exhibited graded effects on plasma sulfate and human height and pinpointed alleles associated with increased odds of diverse musculoskeletal traits and diseases in the population. This integrative approach can identify new players in incompletely characterized human metabolic reactions and reveal metabolic readouts informative of human traits and diseases.

Key Points: Integrated analysis of proteome and metabolome identifies modules associated with CKD progression and kidney failure. Ephrin transmembrane proteins and podocyte-expressed CRIM1 and NPNT emerged as central components and warrant experimental and clinical investigation. Background: Proteins and metabolites play crucial roles in various biological functions and are frequently interconnected through enzymatic or transport processes. Methods: We present an integrated analysis of 4091 proteins and 630 metabolites in the Chronic Renal Insufficiency Cohort study ( N =1708; average follow-up for kidney failure, 9.5 years, with 537 events). Proteins and metabolites were integrated using an unsupervised clustering method, and we assessed associations between clusters and CKD progression and kidney failure using Cox proportional hazards models. Analyses were adjusted for demographics and risk factors, including the eGFR and urine protein–creatinine ratio. Associations were identified in a discovery sample (random two thirds, n =1139) and then evaluated in a replication sample (one third, n =569). Results: We identified 139 modules of correlated proteins and metabolites, which were represented by their principal components. Modules and principal component loadings were projected onto the replication sample, which demonstrated a consistent network structure. Two modules, representing a total of 236 proteins and 82 metabolites, were robustly associated with both CKD progression and kidney failure in both discovery and validation samples. Using gene set enrichment, several transmembrane-related terms were identified as overrepresented in these modules. Transmembrane–ephrin receptor activity displayed the largest odds (odds ratio=13.2, P value = 5.5×10 ⁻⁵ ). A module containing CRIM1 and NPNT expressed in podocytes demonstrated particularly strong associations with kidney failure ( P value = 2.6×10 ⁻⁵ ). Conclusions: This study demonstrates that integration of the proteome and metabolome can identify functions of pathophysiologic importance in kidney disease.

Genetic studies of the metabolome can uncover enzymatic and transport processes shaping human metabolism. Using WES-based rare variant aggregation testing to detect genes associated with levels of 1,294 plasma and 1,396 urine metabolites, we discovered 235 gene-metabolite associations, many previously unreported. Validation through genetic and new computational approaches ( in silico gene knockouts in whole-body models of human metabolism) provided orthogonal evidence that population-based studies of rare, damaging variants in the heterozygous state permit inferences usually obtained from inborn errors of metabolism. Allelic series of functional variants in transporters responsible for transcellular sulfate reabsorption (SLC13A1, SLC26A1) exhibited graded effects on plasma sulfate and human height, and pinpointed alleles that strongly increased risk for dozens of musculoskeletal traits and diseases in the population. We present a powerful approach to identify new players in incompletely characterized human metabolic reactions, and to reveal metabolic readouts of disease risk to inform disease prevention and treatment.

Male-pattern hair loss (MPHL) is common and highly heritable. While genome-wide association studies (GWAS) have generated insights into the contribution of common variants to MPHL etiology, the relevance of rare variants remains unclear. To determine the contribution of rare variants to MPHL etiology, we perform gene-based and single-variant analyses in exome-sequencing data from 72,469 male UK Biobank participants. While our population-level risk prediction suggests that rare variants make only a minor contribution to general MPHL risk, our rare variant collapsing tests identified a total of five significant gene associations. These findings provide additional evidence for previously implicated genes (EDA2R, WNT10A) and highlight novel risk genes at and beyond GWAS loci (HEPH, CEPT1, EIF3F). Furthermore, MPHL-associated genes are enriched for genes considered causal for monogenic trichoses. Together, our findings broaden the MPHL-associated allelic spectrum and provide insights into MPHL pathobiology and a shared basis with monogenic hair loss disorders.

Male-pattern hair loss (MPHL) is a highly heritable and prevalent form of hair loss. While genome-wide association studies (GWAS) have provided i | POSTER