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Hakonarson, H.

Publications and source records attributed to Hakonarson, H..

At least 19 recordsLinked to original sources

Applying AlphaGenome Variant Impact for SNV Prioritization

AlphaGenome Atlas, released in September 2026, provides functional predictions for nearly all possible human single-nucleotide variants using the AlphaGenome Variant Impact (AVI) score. However, empirical thresholds relating AVI quantile rank (AVI_QUANTILE) to clinical variant classifications have not been established. We derived AVI_QUANTILE thresholds distinguishing ClinVar pathogenic, likely pathogenic, uncertain, conflicting, likely benign, and benign SNVs using receiver operating characteristic analyses. Pathogenic/likely pathogenic variants were strongly enriched at the upper end of the AVI_QUANTILE distribution, yielding a Youden-optimal ClinVar-derived cutoff of 0.9938. Optimal cutoffs were generally consistent across several major molecular consequence classes, although lower thresholds were observed for selected noncoding categories. Similarly, most well-powered gene-disease groups showed cutoffs close to the global threshold, with modest gene-specific variation. Among 24,989 variants of uncertain significance, 11,357 (45.45%) exceeded the global cutoff, identifying a substantial subset with AlphaGenome-predicted functional effects comparable to those observed among pathogenic/likely pathogenic variants and potentially warranting further evaluation. In a steroid-dependent asthma fine-mapping analysis, AVI_QUANTILE showed little correspondence with SuSiE posterior inclusion probabilities, indicating that AlphaGenome functional predictions capture information distinct from statistical fine-mapping.

genomics↗

CRISPR screening reveals SYCP3 as a key driver of metastasis in prostate cancer

Prostate cancer (PCa) is a prevalent male cancer with high survival rates, except in advanced or metastatic stages, for which effective treatments are lacking. Metastatic PCa involves complex mechanisms including loss of tumor suppressor genes and DNA repair molecules, which impacts therapy responses. We have reanalyzed data from a CRISPR/Cas9 genome wide screening previously performed to identify essential regulators of invasive abilities of the metastatic cell line DU145 identifying SYCP3 as a regulator of metastatic invasion. Subsequent analyses of tumor samples demonstrated that SYCP3 expression is frequently upregulated in PCa tumors from patients in advanced stages. Furthermore, SYCP3 genetic depletion significantly reduced the invasive and migratory abilities of DU145 cells and increased their adhesion capacity. Additionally, and due to the implication of SYCP3 on DNA repair processes, we have analyzed the role of SYCP3 on the cellular response to radiotherapy (RT) and found that its depletion induced RT resistance, suggesting a role for SYCP3 in DNA damage response and genomic instability. All these data support a role for SYCP3 in PCa metastasis and provides opportunities for personalized medicine.

cancer biology↗

Companion to: A molecular basis for milk allergen immune recognition in eosinophilic esophagitis

BackgroundEosinophilic esophagitis (EoE) is a chronic, type 2 inflammatory disease that is increasing in incidence and has substantial morbidity. Despite being clinically defined as a food allergy, the molecular details of food antigen presentation and recognition by the immune system are unknown. ObjectiveThe objective of this study was to identify and characterize the molecular basis of milk antigen presentation and T cell recognition in a patient with EoE milk allergy. MethodsMilk-expanded TCR clonotypes were identified using ex vivo stimulation followed by single cell RNA with linked, paired TRA and TRB sequencing. HLA restriction and antigen specificity of TCRs were identified using a combination of lentiviral expression, HLA sequencing, antibody blockade, and a peptide library screen. ResultsWe isolated a {beta}-casein specific TCR clonotype (eoeTCR-4) and determined its HLA restriction (HLA-DRB1*07:01) and cognate antigen ({beta}-casein AA 59-78). EoeTCR-4 was not detected among a larger group of subjects and is likely private to EoE Subject 1. ConclusionIn conjunction with the parent manuscript, this companion article provides the first molecular identity of food antigen presentation and immune recognition in EoE. SUMMARYThis manuscript is a companion to the parent manuscript "A molecular basis for milk allergen immune recognition in eosinophilic esophagitis". It provides additional data and detailed methods not provided in the parent manuscript. It is designed to supplement and support the findings and conclusions of the parent manuscript.

immunology↗

Single-Cell Omics for Transcriptome CHaracterization (SCOTCH): isoform-level characterization of gene expression through long-read single-cell RNA sequencing

Recent advances in long-read single-cell transcriptome sequencing (lr-scRNA-Seq) enable full-length isoform profiling at single-cell resolution. We present SCOTCH (Single-Cell Omics for Transcriptome CHaracterization), an end-to-end, platform-independent pipeline for isoform characterization from lr-scRNA-Seq data, supporting Nanopore and PacBio sequencing as well as 10X Genomics and Parse Biosciences protocols. SCOTCH models isoforms as combinations of non-overlapping sub-exons and applies dynamic thresholding for robust isoform assignment while efficiently address ambiguous mapping issues. By refining sub-exon boundaries through integration of read coverage with existing annotations and applying an iterative clustering strategy to reconstruct novel transcripts, SCOTCH reliably recovers more true novel isoforms than existing splice-graph-based methods, with poly(A)-aware filtering further reducing false-positive structures. Extensive simulations demonstrate improved quantification of known isoforms and enhanced reconstruction of novel isoforms. Analyses of human blood and cerebral organoid datasets across multiple platforms further confirm SCOTCHs ability to resolve cell-type-specific transcriptome profiles and uncover experimentally supported novel isoforms.

bioinformatics↗

CRISPR/Cas9 screenings unearth protein arginine methyltransferase 7 as a novel driver of metastasis in prostate cancer

Owing to the inefficacy of available treatments, the survival rate of patients with metastatic prostate cancer (mPCa) is severely decreased. Therefore, it is crucial to identify new therapeutic targets to increase their survival. This study aim was to identify the most relevant regulators of mPCa onset by performing two high-throughput CRISPR/Cas9 screenings. Furthermore, some of the top hits were validated using small interfering RNA (siRNA) technology, with protein arginine methyltransferase 7 (PRMT7) being the best candidate. Its inhibition or depletion via CRISPR significantly reduced mPCa cell capacities in vitro. Moreover, PRMT7 ablation reduced mPCa appearance in chicken chorioallantoic membrane and mouse xenograft assays. Molecularly, PRMT7 reprograms the expression of several adhesion molecules through methylation of several transcription factors, such as FoxK1 or NR1H2, which results in primary tumor PCa cell adhesion loss and motility gain. Importantly, PRMT7 is upregulated in advanced stages of Spanish PCa tumor samples and PRMT7 pharmacological inhibition reduces the dissemination of mPCa cells. Thus, here is shown that PRMT7 is a potential therapeutic target and biomarker of mPCa.

cancer biology↗

Human T follicular helper clones seed the germinal center-resident regulatory pool

How FOXP3+ T follicular regulatory (Tfr) cells simultaneously steer antibody formation toward microbe/vaccine recognition and away from self-reactivity remains unsettled. To explore human Tfr cell provenance, function and location heterogeneity, we used paired TCRVA/TCRVB sequencing to distinguish tonsillar Tfr cells clonally related to natural Tregs (nTfr) from those likely induced from Tfh cells (iTfr). The proteins iTfr and nTfr cells differentially expressed were utilized to pinpoint their in situ locations via multi-plex microscopy and establish divergent functional roles. In-silico and tonsil organoid tracking models corroborated the existence of separate Treg-to-nTfr and Tfh-to-iTfr developmental trajectories. In total, we have identified human iTfr cells as a distinct CD38-expressing, GC-resident, Tfh-descended subset that gains suppressive function while retaining capacities for B-cell help whereas CD38- nTfr cells are elite suppressors primarily localized to follicular mantles. Interventions differentially targeting Tfr subsets may provide therapeutic opportunities to boost immunity or more precisely treat autoimmune diseases. One sentence summaryHuman tonsillar Tfr clones descend from either Treg or Tfh lineages and provenance predicts their TCR repertoires, locations and functional characteristics.

immunology↗

Oncogene-induced matrix reorganization controls CD8+ T cell function in the tumor microenvironment

CD8+ T cell dysfunction impedes anti-tumor immunity in solid cancers but the underlying mechanisms are diverse and poorly understood. Extracellular matrix (ECM) composition has been linked to both impaired T cell migration and enhanced tumor progression; however, impacts of individual ECM molecules on T cell function in the tumor microenvironment (TME) are only beginning to be elucidated. Upstream regulators of aberrant ECM deposition and organization in solid tumors are equally ill-defined. Therefore, we investigated how ECM composition modulates CD8+ T cell function in undifferentiated pleomorphic sarcoma (UPS), an immunologically active and desmoplastic tumor. Using an autochthonous murine model of UPS and data from multiple human patient cohorts, we discovered a multifaceted mechanism wherein the transcriptional co-activator YAP1 promotes collagen VI (COLVI) deposition in the UPS TME. In turn, COLVI induces CD8+ T cell dysfunction and immune evasion by remodeling fibrillar collagen and inhibiting T cell autophagic flux. Unexpectedly, collagen I (COLI) opposed COLVI in this setting, promoting CD8+ T cell function and acting as a tumor suppressor. Thus, CD8+ T cell responses in sarcoma depend upon oncogene-mediated ECM composition and remodeling.

cancer biology↗

Ancestral diversity improves discovery and fine-mapping of genetic loci for anthropometric traits - the Hispanic/Latino Anthropometry Consortium

Hispanic/Latinos have been underrepresented in genome-wide association studies (GWAS) for anthropometric traits despite notable anthropometric variability with ancestry proportions, and a high burden of growth stunting and overweight/obesity in Hispanic/Latino populations. This address this knowledge gap, we analyzed densely-imputed genetic data in a sample of Hispanic/Latino adults, to identify and fine-map common genetic variants associated with body mass index (BMI), height, and BMI-adjusted waist-to-hip ratio (WHRadjBMI). We conducted a GWAS of 18 studies/consortia as part of the Hispanic/Latino Anthropometry (HISLA) Consortium (Stage 1, n=59,769) and validated our findings in 9 additional studies (HISLA Stage 2, n=9,336). We conducted a trans-ethnic GWAS with summary statistics from HISLA Stage 1 and existing consortia of European and African ancestries. In our HISLA Stage 1+2 analyses, we discovered one novel BMI locus, as well two novel BMI signals and another novel height signal, each within established anthropometric loci. In our trans-ethnic meta- analysis, we identified three additional novel BMI loci, one novel height locus, and one novel WHRadjBMI locus. We also identified three secondary signals for BMI, 28 for height, and two for WHRadjBMI. We replicated >60 established anthropometric loci in Hispanic/Latino populations at genome-wide significance--representing up to 30% of previously-reported index SNP anthropometric associations. Trans-ethnic meta-analysis of the three ancestries showed a small-to-moderate impact of uncorrected population stratification on the resulting effect size estimates. Our novel findings demonstrate that future studies may also benefit from leveraging differences in linkage disequilibrium patterns to discover novel loci and additional signals with less residual population stratification.

genetics↗

Genomic Considerations for FHIR; eMERGE Implementation Lessons

Structured representation of clinical genetic results is necessary for advancing precision medicine. The Electronic Medical Records and Genomics (eMERGE) Networks Phase III program initially used a commercially developed XML message format for standardized and structured representation of genetic results for electronic health record (EHR) integration. In a desire to move towards a standard representation, the network created a new standardized format based upon Health Level Seven Fast Healthcare Interoperability Resources (HL7 FHIR), to represent clinical genomics results. These new standards improve the utility of HL7 FHIR as an international healthcare interoperability standard for management of genetic data from patients. This work advances the establishment of standards that are being designed for broad adoption in the current health information technology landscape.

genomics↗

Targeting CSF-1 ameliorates experimental autoimmune encephalomyelitis by depleting inflammatory monocytes and microglia in the central nervous system without affecting quiescent microglia.

The receptor for colony stimulating factor 1 (CSF-1R) is important for the survival and function of myeloid cells that mediate pathology during experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). CSF-1 and IL-34, the ligands of CSF-1R, have similar bioactivities but distinct tissue and context-dependent expression patterns, suggesting that they have different roles. This could be the case in EAE, given that CSF-1 expression is upregulated in the CNS, while IL-34 remains constitutively expressed. We found that targeting CSF-1 with neutralizing mAb halted ongoing EAE, with efficacy superior to CSF-1R inhibitor BLZ945, whereas IL-34 neutralization had no effect, suggesting that pathogenic myeloid cells were maintained by CSF-1, not IL-34. Both anti-CSF-1- and BLZ945-treatment greatly reduced numbers of monocyte-derived cells and microglia in the CNS. However, anti-CSF-1 selectively depleted inflammatory microglia and monocytes in inflamed CNS areas, whereas BLZ945 depleted virtually all myeloid cells, including quiescent microglia, throughout the CNS. Anti-CSF-1 treatments reduced the size of demyelinated lesions, and microglial activation in the grey matter. Lastly, we found that bone marrow-derived immune cells were the major mediators of CSF-1R-dependent pathology, while microglia played a lesser role. Our findings suggest that targeting CSF-1 could be effective in ameliorating MS pathology, while preserving the homeostatic functions of myeloid cells, thereby minimizing risks associated with total ablation of CSF-1R-dependent cells. Significance StatementMultiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE), are autoimmune diseases characterized by accumulation of myeloid immune cells into the central nervous system (CNS). Both harmful and beneficial myeloid cells are present in EAE/MS, and a goal of MS therapy is to preferentially remove harmful myeloid cells. The receptor for CSF-1 (CSF-1R) is found on myeloid cells and it is important for their survival. CSF-1R can bind two ligands, CSF-1 and IL-34, but is unknown whether their functions in EAE/MS differ. We found that blocking CSF-1 depleted only harmful myeloid cells in the CNS and suppressed EAE, whereas blocking IL-34 had no effect. Thus, we propose that blocking CSF-1 could be a novel therapy for MS.

immunology↗

RUNX1 haploinsufficiency causes a marked deficiency of megakaryocyte-biased hematopoietic progenitor cells: Mechanistic studies and drug correction

Patients with familial platelet disorder with a predisposition to myeloid malignancy (FPDMM) harbor germline monoallelic mutations in a key hematopoietic transcription factor RUNX1. Previous studies of FPDMM have focused on megakaryocyte (Mk) differentiation, and platelet production and signaling. However, the effects of RUNX1 haploinsufficiency on hematopoietic progenitor cells (HPCs) and subsequent megakaryopoiesis remains incomplete. To address this issue, we studied induced-pluripotent stem cell (iPSC)-derived HPCs (iHPCs) and Mks (iMks) from both patient-derived lines and a wildtype line modified to be RUNX1 haploinsufficient (RUNX1+/-), each compared to their isogenic wildtype control. All RUNX1+/- lines showed decreased iMk yield and depletion of a Mk-biased iHPC subpopulation. To investigate global and local gene expression changes underlying this iHPC shift, single-cell RNA sequencing was performed on sorted FPDMM and control iHPCs. We defined several cell subpopulations in FPDMM Mk-biased iHPCs. Analyses of gene sets upregulated in FPDMM iHPCs indicated enrichment for response to stress, regulation of signal transduction and response to cytokine gene sets. Immunoblotting studies in FPDMM iMks were consistent with these findings, but also identified augmented baseline c-Jun N-terminal kinase (JNK) phosphorylation, known to be activated by transforming growth factor {beta}1 and cellular stressors. J-IN8 and RepSox, small drugs targeting these pathways, corrected quantitative defects in FPDMM iHPC production. These findings were confirmed in adult human CD34+-derived stem and progenitor cells transduced with lentiviral RUNX1 short-hairpin (sh) RNA to mimic RUNX1+/-. These mechanistic studies of the defect in megakaryopoiesis in FPDMM suggest druggable pathways for clinical management of thrombocytopenia in affected patients. Key pointsO_LIRUNX1 haploinsufficiency results in a deficiency of megakaryocyte-biased hematopoietic progenitor cells (HPCs). C_LIO_LIRUNX1 haploinsufficiency elevates druggable proinflammatory and TGF{beta}R1-related pathways in HPCs. C_LI

molecular biology↗

Risk of preeclampsia in patients with genetic predisposition to common medical conditions: a case-control study

ObjectiveTo assess whether women with a genetic predisposition to medical conditions known to increase preeclampsia risk have an increased risk of preeclampsia in pregnancy. DesignCase-control study. Setting and populationPreeclampsia cases (n=498) and controls (n=1864) of European ancestry from 5 US sites genotyped on a cardiovascular gene-centric array. MethodsSignificant single nucleotide polymorphisms (SNPs) from 21 traits in 7 disease categories (cardiovascular, inflammatory/autoimmune, insulin resistance, liver, obesity, renal, thrombophilia) with published genome-wide association studies (GWAS) were used to create a genetic instrument for each trait. Multivariable logistic regression was used to test the association of each continuous, scaled genetic instrument with preeclampsia. Odds of preeclampsia were compared across quartiles of the genetic instrument and evaluated for significance using a test for trend. Main Outcome Measurespreeclampsia. ResultsAn increasing burden of risk alleles for elevated diastolic blood pressure (DBP) and increased body mass index (BMI) were associated with an increased risk of preeclampsia (DBP: overall OR 1.11 (1.01-1.21), p=0.025; BMI: OR 1.10 (1.00-1.20), p=0.042), while risk alleles associated with elevated alkaline phosphatase (ALP) were protective (OR 0.89 (0.82-0.97), p=0.008), driven primarily by pleiotropic effects of variants in the FADS gene region. The effect of DBP genetic loci was even greater in early-onset (<34 weeks) preeclampsia cases (OR 1.30 (1.08-1.56), p=0.005). For all other traits, the genetic instrument was not robustly associated with preeclampsia risk. ConclusionsThese results suggest that the underlying genetic architecture of preeclampsia is shared with other disorders, specifically hypertension and obesity. TWEETABLE ABSTRACTGenetic predisposition to increased diastolic blood pressure and obesity increases the risk of preeclampsia.

genetics↗

Genome wide association analysis in dilated cardiomyopathy reveals two new key players in systolic heart failure on chromosome 3p25.1 and 22q11.23

We present the results of the largest genome wide association study (GWAS) performed so far in dilated cardiomyopathy (DCM), a leading cause of systolic heart failure and cardiovascular death, with 2,719 cases and 4,440 controls in the discovery population. We identified and replicated two new DCM-associated loci, one on chromosome 3p25.1 (lead SNP rs62232870, p = 8.7 x 10-11 and 7.7 x 10-4 in the discovery and replication step, respectively) and the second on chromosome 22q11.23 (lead SNP rs7284877, p = 3.3 x 10-8 and 1.4 x 10-3 in the discovery and replication step, respectively) while confirming two previously identified DCM loci on chromosome 10 and 1, BAG3 and HSPB7. The genetic risk score constructed from the number of lead risk-alleles at these four DCM loci revealed that individuals with 8 risk-alleles were at a 27% increased risk of DCM compared to individuals with 5 risk alleles (median of the referral population). We estimated the genome wide heritability at 31% {+/-} 8%. In silico annotation and functional 4C-sequencing analysis on iPSC-derived cardiomyocytes strongly suggest SLC6A6 as the most likely DCM gene at the 3p25.1 locus. This gene encodes a taurine and beta-alanine transporter whose involvement in myocardial dysfunction and DCM is supported by recent observations in humans and mice. Although less easy to discriminate the better candidate at the 22q11.23 locus, SMARCB1 appears as the strongest one. This study provides both a better understanding of the genetic architecture of DCM and new knowledge on novel biological pathways underlying heart failure, with the potential for a therapeutic perspective.

genomics↗

Single-cell transcriptomic profile reveals macrophage heterogeneity in medulloblastoma and their treatment-dependent recruitment

The role of macrophages in medulloblastoma, the most common malignant pediatric brain tumor, is unclear. Using single-cell RNA sequencing in a mouse model of sonic hedgehog medulloblastoma and analysis of bulk RNA sequencing of human medulloblastoma, we investigated macrophage heterogeneity. Our findings reveal differential recruitment of macrophages with molecular-targeted versus radiation therapy and identify an immunosuppressive monocyte-derived macrophages following radiation treatment of mouse medulloblastoma, uncovering potential strategies for immunomodulation as adjunctive therapy.

cancer biology↗

A polygenic and phenotypic risk prediction for Polycystic Ovary Syndrome evaluated by Phenome-wide association studies

PurposeAs many as 75% of patients with Polycystic ovary syndrome (PCOS) are estimated to be unidentified in clinical practice. Utilizing polygenic risk prediction, we aim to identify the phenome-wide comorbidity patterns characteristic of PCOS to improve accurate diagnosis and preventive treatment.\n\nMethods and FindingsLeveraging the electronic health records (EHRs) of 124,852 individuals, we developed a PCOS risk prediction algorithm by combining polygenic risk scores (PRS) with PCOS component phenotypes into a polygenic and phenotypic risk score (PPRS). We evaluated its predictive capability across different ancestries and perform a PRS-based phenome-wide association study (PheWAS) to assess the phenomic expression of the heightened risk of PCOS. The integrated polygenic prediction improved the average performance (pseudo-R2) for PCOS detection by 0.228 (61.5-fold), 0.224 (58.8-fold), 0.211 (57.0-fold) over the null model across European, African, and multi-ancestry participants respectively. The subsequent PRS-powered PheWAS identified a high level of shared biology between PCOS and a range of metabolic and endocrine outcomes, especially with obesity and diabetes: morbid obesity, type 2 diabetes, hypercholesterolemia, disorders of lipid metabolism, hypertension and sleep apnea reaching phenome-wide significance.\n\nConclusionsOur study has expanded the methodological utility of PRS in patient stratification and risk prediction, especially in a multifactorial condition like PCOS, across different genetic origins. By utilizing the individual genome-phenome data available from the EHR, our approach also demonstrates that polygenic prediction by PRS can provide valuable opportunities to discover the pleiotropic phenomic network associated with PCOS pathogenesis.

bioinformatics↗

Epistasis Detection using Model-Based Multifactor Dimensionality Reduction in Structured Populations

In genome-wide association studies, the extent and impact of confounding due population structure have been well recognized. Inadequate handling of such confounding is likely to lead to spurious associations, hampering replication and the identification of causal variants. Several strategies have been developed for protecting associations against confounding, the most popular one is based on Principal Component Analysis. In contrast, the extent and impact of confounding due to population structure in gene-gene interaction association epistasis studies are much less investigated and understood. In particular, the role of non-linear genetic population substructure in epistasis detection is largely under-investigated, especially outside a regression framework. In order to identify causal variants in synergy, to improve interpretability and replicability of epistasis results, we introduce three strategies based on model-based multifactor dimensionality reduction (MB-MDR) approach for structured populations. We demonstrate through extensive simulation studies the effect of various degrees of genetic population structure and relatedness on epistasis detection and propose appropriate remedial measures based on linear and non-linear sample genetic similarity. Authors SummaryOne of the biggest challenges in human genetics is to understand the genetic basis of complex diseases such as cancer, diabetes, heart disease, depression, asthma, inflammatory bowel disease and hypertension, for instance via identifying genes, gene-gene and gene-environment interactions in association studies. Over the years, a more prominent role has been given to gene-gene interaction (epistasis) detection, in view of precision medicine and the hunt for novel drug targets and biomarkers. However, the increasing number of consortium-based epistasis studies that are marked by heterogeneous sample collections due to population structure or shared genetic ancestry are likely to be prone to spurious association and low power detection of associated or causal genes. In this work we introduced various strategies in epistasis studies with correction for confounding due to population structure. Based on extensive simulation studies we demonstrated the effect of genetic population structure on epistasis detection and investigated remedial measures to confounding by linear and nonlinear sample genetic similarity.

bioinformatics↗

Ultra-rare genetic variation in the epilepsies: a whole-exome sequencing study of 17,606 individuals

Sequencing-based studies have identified novel risk genes for rare, severe epilepsies and revealed a role of rare deleterious variation in common epilepsies. To identify the shared and distinct ultra-rare genetic risk factors for rare and common epilepsies, we performed a whole-exome sequencing (WES) analysis of 9,170 epilepsy-affected individuals and 8,364 controls of European ancestry. We focused on three phenotypic groups; the rare but severe developmental and epileptic encephalopathies (DEE), and the commoner phenotypes of genetic generalized epilepsy (GGE) and non-acquired focal epilepsy (NAFE). We observed that compared to controls, individuals with any type of epilepsy carried an excess of ultra-rare, deleterious variants in constrained genes and in genes previously associated with epilepsy, with the strongest enrichment seen in DEE and the least in NAFE. Moreover, we found that inhibitory GABAA receptor genes were enriched for missense variants across all three classes of epilepsy, while no enrichment was seen in excitatory receptor genes. The larger gene groups for the GABAergic pathway or cation channels also showed a significant mutational burden in DEE and GGE. Although no single gene surpassed exome-wide significance among individuals with GGE or NAFE, highly constrained genes and genes encoding ion channels were among the top associations, including CACNA1G, EEF1A2, and GABRG2 for GGE and LGI1, TRIM3, and GABRG2 for NAFE. Our study confirms a convergence in the genetics of common and rare epilepsies associated with ultra-rare coding variation and highlights a ubiquitous role for GABAergic inhibition in epilepsy etiology in the largest epilepsy WES study to date.

genetics↗

Clinical and Functional Characterization of Melanocortin 4 Receptor genetic variants in African American and/or Hispanic children with severe early onset obesity.

ContextMutations in melanocortin receptor (MC4R) are the most frequent cause of monogenic obesity in children of European ancestry, but little is known about their prevalence in children from minority populations in the United States.\n\nObjectiveThis study aims to identify the prevalence of MC4R mutations in children with severe early onset obesity of African-American and/or Latina ancestry.\n\nDesign and SettingIndividuals were recruited from the weight management clinics at two hospitals and from the institutional biobank at a third hospital. Sequencing of the MC4R gene was performed by whole exome and/or Sanger sequencing. Functional testing was performed to establish the surface expression of the receptor and cAMP response to its cognate ligand -melanocyte stimulating hormone.\n\nParticipantsThree hundred and twelve children (1-18 years, 50% girls) with body mass index (BMI) > 120% of 95th percentile of CDC 2000 growth charts at an age < 6 years, with no known pathological cause of obesity were enrolled.\n\nResultsEight rare MC4R mutations (2.6%) were identified in this study (R7S, F202L (n=2), M215I, G252D, V253I, I269N, F284I), three of which have not been previously reported (M215I, G252D, F284I). The pathogenicity of the variants was confirmed either by prior literature reports, or by functional testing. There was no significant difference in the BMI or height trajectories of children with or without MC4R mutations in this cohort.\n\nConclusionsWhile the prevalence of MC4R mutations in this cohort was similar to that reported in obese children of European ancestry, some of the variants were novel.

genetics↗