Polycystic ovary syndrome (PCOS) and its underlying features remain poorly understood. In this genetic study (n = 544,513), we expand the number of genetic loci from 16 to 29, and additionally identify 31 associated plasma proteins. Many risk-increasing loci were associated with later age at menopause, underscoring the reproductive longevity related to an increased oocyte number and/or availability across the lifespan. Hormonal regulation in the etiology of this condition, through metabolic and reproductive features, was emphasized. The proteomic analysis highlighted metabolic biology known to be related to PCOS. A polygenic risk score (PRS) was associated with adverse cardiometabolic outcomes, with differing relevance of testosterone and body mass index in women and men. Finally, while oligo-anovulation and anovulatory infertility are features of PCOS, we observed no impact of PCOS susceptibility on childlessness. We suggest that PCOS susceptibility confers balanced pleiotropic influences on fertility in women, and life-long adverse metabolic consequences in both sexes.

ContextThyroid hormones affect neurological development and function, but detailed studies of thyroid hormones and metabolites in autism are lacking.ObjectiveTo characterize thyroid function and metabolism in autistic children.MethodologyThis cross-sectional study compared 788 autistic children (mean age 7.6 ± 3.9 years, 78% male) with 301 non-autistic children (mean age 7.8 ± 4.0 years, 48% male; comprising 215 (71.4%) non-autistic siblings of participants and 86 (28.6%) unrelated individuals). Plasma TSH, free T4 (FT4) and free T3 (FT3) were measured by automated immunoassay, and total T4, total T3 and thyroid hormone metabolites by customized liquid chromatography-tandem mass spectrometry (LCMS/MS). Regression analyses were adjusted for age and sex.ResultsTSH concentrations were similar in autistic and non-autistic children (median 2.3 vs 2.1 mU/L, P = 0.64). FT4 was significantly lower in autistic children (18.4 vs 18.7 pmol/L, P = 0.0003), as was FT3 (7.0 vs 7.1pmol/L, P<0.0001), with no significant difference in the FT4:FT3 ratio (P = 0.24). Total T4 was lower in autistic children (178 vs 194 nmol/L, P = 0.0026, as was total T3 (2.2 vs 2.4 nmol/L, P = 0.018), with no significant difference in the T4:T3 ratio (P = 0.099). Two metabolites were significantly lower in autistic children: 3,5-T2 (0.010 vs 0.021 nmol/L, P<0.0001) and 3,3’-T2 (0.12 vs 0.16 nmol/L, P<0.0001), whereas T0 levels were higher (1.5 vs 1.1 nmol/L, P = 0.028).ConclusionsCirculating thyroid hormones and metabolites differ between autistic and non-autistic children, although the observed differences are small. The study demonstrates the utility of LCMS/MS for in-depth characterization of thyroid hormone economy, with potentially wide applications.

Current antiresorptive therapies reduce bone loss by eliminating osteoclasts or inhibiting their formation. However, these approaches could disrupt osteoclast-osteoblast communication and cause serious complications with long-term usage. There is a need for developing new therapies that selectively inhibit resorptive function, while preserving osteoclast-mediated coupling effects to osteoblasts. Sorting nexin 10 (SNX10), an autosomal recessive osteopetrosis (ARO)-associated gene, plays a role mainly in osteoclast bone resorptive function. However, its potential as a target for developing therapeutic agents for bone disorders remains unexplored. In this study, we employed a multi-step approach combining artificial intelligence (AI)-driven virtual screening with high-throughput screening methods and functional assays to identify small molecules targeting SNX10 that inhibit bone resorption without impairing osteoclast formation. Our lead compound AW-006 emerged as the top candidate across all validation methods, selectively inhibiting osteoclast resorptive function while maintaining normal osteoclastogenesis in vitro. Mechanistic analyses indicated that AW-006 interacts with SNX10 and reduces its thermal stability, while molecular docking predicted binding within the PI(3)P-binding pocket and associated conformational changes affecting residues involved in PI(3)P binding and structural integrity. We discovered that SNX10 interacts with the key vesicular trafficking regulator Rab7 in living cells, and AW-006 abnormally enhances this interaction, dysregulating normal podosome belt formation in osteoclasts. Furthermore, the compound's anti-resorptive efficacy was validated in ovariectomized mice, demonstrating its therapeutic potential in estrogen deficiency-induced bone loss. Our study identifies AW-006 as a novel anti-resorptive candidate and highlights SNX10 as a promising therapeutic target for bone disorders.

Context:A rare cause of hypocalcemia, autosomal dominant hypocalcemia type 1 (ADH1) arises from a gain-of-function variant of the calcium-sensing receptor gene (CASR). Objective:Three patients from 2 unrelated families, presenting with hypocalcemia and other biochemical parameters consistent with ADH1, were examined for variants in the CASR with the aim to functionally assess any variant detected to confirm the ADH1 diagnosis. Methods:Sanger sequencing of the coding region of the CASR from the 3 patients identified a single CASR variant that was generated by site-directed-mutagenesis in the CASR as a FLAG-tagged construct in the mammalian expression vector pcDNA3.1. The variant's expression in HEK293 cells (compared to FLAG-tagged wild-type [WT] receptor) was assessed by Western blot analysis and its activity measured following calcium dosing experiments using an IP-One enzyme-linked immunosorbent assay. Results:Sequence analysis revealed the presence of a heterozygous missense variant in the CASR, an adenine to guanine transition at nucleotide 1256 causing an asparagine to serine substitution at amino acid 419 (N419S) in the CaSR's Venus flytrap domain in all 3 patients. The N419S variant showed a modest increase in expression compared to the WT receptor. Significantly, the IP-One assay demonstrated that the variant is constitutively active in the absence of Ca++ ions and that this gain-of-function is maintained at physiologically relevant Ca++ ion concentrations. Conclusion:The N419S CASR variant affecting 2 separate families is constitutively activating and therefore causative of ADH1. This is the first report of a constitutively active variant affecting the extracellular domain of the CaSR.

Abstract The kidney is a highly energetic organ, requiring substantial ATP production through mitochondrial oxidative phosphorylation to support tubular reabsorption. Metabolic reprogramming and impaired mitochondrial function are implicated in diabetic kidney disease, yet direct assessment of mitochondrial respiratory flux in the human kidney has been constrained by limited access to freshly obtained tissue. Consequently, much of the evidence supporting altered renal mitochondrial function in diabetes derives from animal models that do not fully recapitulate the human condition. We established a workflow for real-time bioenergetic profiling of fresh kidney cortex obtained during nephrectomy from living individuals with diabetes and preserved kidney function. Mitochondrial respiration, electron transport system activity and tubular mitochondrial morphology were compared with age- and sex-matched, histopathologically normal non-diabetic controls. High-resolution respirometry revealed increased mitochondrial respiratory flux in permeabilised diabetic kidney cortex. In contrast, mitochondria isolated from the same tissue exhibited reduced respiratory capacity and impaired complex I activity. Quantitative analysis of tubular cells demonstrated increased mitochondrial volume density together with greater mitochondrial fragmentation in diabetes. These findings reveal that the human kidney undergoes substantial metabolic adaptation early in diabetes, before measurable loss of kidney function. Increased tissue-level respiratory flux despite intrinsic mitochondrial impairment suggests that expansion and remodelling of the mitochondrial network may initially compensate for reduced organelle efficiency and sustain the kidney’s high energetic demands. This compensatory state may, however, increase metabolic stress and vulnerability to subsequent kidney injury. To our knowledge, this study provides the first direct tissue-level functional evidence that mitochondrial metabolism is reprogrammed in the human kidney in diabetes before measurable kidney dysfunction develops. It defines an early bioenergetic signature characterised by tissue hypermetabolism despite impaired mitochondria-specific respiratory capacity, challenging the concept that diabetes produces a uniform decline in renal mitochondrial function. Failure to sustain this adaptive state may represent a critical transition towards diabetic kidney disease. GRAPHICAL ABSTRACT One Sentence Summary Diabetes drives early metabolic reprogramming of the human kidney before measurable kidney dysfunction

Background/Objectives: Autism spectrum disorder (ASD), a neurodevelopmental condition characterised by social and communication differences, is complex and aetiologically heterogeneous. Untargeted metabolomics is emerging as a tool in screening for biochemical abnormalities. This research was conducted using the Australian Autism Biobank resource and involved analysis of plasma metabolites to characterise metabolite differences between autistic children and controls. Methods: We sought to identify molecular signatures in the plasma of study subjects using mass-spectrometry methods. We included 955 untargeted plasma metabolites from autistic children (n = 491; 2–18 years; 78% male) and control subjects (n = 97; 2–17 years of age; 51% male). Statistical analyses were performed using questionnaire data for both groups, including standardised scores from the Autism Diagnostic Observation Schedule—Second Edition (ADOS-2), which measures the severity of autism-related behaviours. We also evaluated intellectual disability by examining the relationships between metabolites and clinical phenotypes. Results: After controlling the false discovery rate at 5%, we identified significant negative associations between the uncharacterised metabolites X-21383 and X-24970 and ASD status (p = 1.85 × 10−6 and p = 1.92 × 10−5 respectively). X-21383 was also found to be significantly reduced in autistic children with coexisting intellectual disability when compared with controls (p = 6.06 × 10−6). No significant associations were identified between the metabolite data and ADOS-2 scores. However, greater levels of X-16938, N1-methyladenosine, and 2-oxoarginine were found to be suggestively associated with higher ADOS-2 scores (p = 2.95 × 10−4–9.6 × 10−5). Conclusion: This metabolomics study in the Australian Autism Biobank has identified several novel metabolites associated with core autism diagnostic behaviours.

Bone undergoes life-long remodeling, in which disorders of bone remodeling could occur in many pathological conditions including osteoporosis. Understanding the cellular metabolism of osteoclasts (OCs) is key to developing new treatments for osteoporosis, a disease that affects over 200 million women worldwide per annum. We found that human OC differentiation from peripheral blood mononuclear cells derived from 8 female patients is featured with a distinct gene expression profile of mitochondrial biogenesis. Elevated mitochondrial membrane potential (MMP, Δψm) was also observed in receptor activator of NF-κB ligand (RANKL)-induced OCs. Interestingly, the gene pathways of heme synthesis and metabolism were activated upon RANKL stimulation, featured by transcriptomic profiling in murine cells at a single-cell resolution, which revealed a stepwise expression pattern of heme-related genes. The real-world human data also divulges potential links between heme-related genes and bone mineral density. Heme is known to have a role in the formation of functional mitochondrial complexes that regulate MMP. Disruption of heme biosynthesis via genetically silencing Ferrochelatase or a selective inhibitor, N-methyl Protoporphyrin IX (NMPP), demonstrated potent inhibition of OC differentiation, with a dose-dependent effect observed in NMPP treatment and a substantial efficacy even at a single dose. In vivo study further showed the protective effect of NMPP on ovariectomy-induced bone loss in female mice. Collectively, we found that RANKL-mediated signaling regulated mitochondrial formation and heme metabolism to synergistically support osteoclastogenesis. Inhibition of heme synthesis impaired OC formation and reversed excessive bone loss, representing a new therapeutic target for metabolic skeletal disorders.

Osteoporosis, a widespread skeletal disorder, arises from excessive bone loss, heightening fragility and fracture risk. Osteoclasts, the major type of bone-resorbing cells, are believed to contribute to this loss. Osteoclast bone resorption relies on 2 important organelles: lysosomes for matrix degradation and mitochondria for energy supply. Iron, a critical linker between lysosomes and mitochondria, has emerged as a critical mediator of osteoclast activity. However, the intricate interplay between lysosomes, mitochondria, and iron in osteoclasts and osteoporosis remains poorly understood. This review aims to bridge this knowledge gap by examining the lysosome–iron–mitochondria axis in osteoclasts. Firstly, we summarized the modulatory function of lysosomes in iron metabolism and iron’s involvement in lysosomal biogenesis and function. Next, we conducted a comprehensive analysis on the contribution of iron in mitochondrial function and its implications for osteoclast activity. Subsequently, we highlighted emerging insights into the lysosome–mitochondria crosstalk in iron metabolism. Finally, we delved into the discussion of how dysregulation of this lysosome–iron–mitochondria axis may drive osteoporosis progression and proposed innovative therapeutic strategies targeting this axis to mitigate osteoclast-mediated bone loss.

IntroductionPolycystic ovary syndrome (PCOS) is a common, but clinically heterogeneous, condition. This study explores PCOS subtypes using two orthogonal statistical analyses of biochemical and anthropometric data.MethodsUnsupervised hierarchical cluster analysis and principal component analysis (PCA) of hormonal and metabolic parameters were performed in a cohort of PCOS-affected women, diagnosed based on the NIH criteria. Data collected included body mass index (BMI), blood pressure (BP), fasting insulin and glucose (HOMA-IR), gonadotropins, androgens, and lipids. Subtypes were explored using unsupervised hierarchical cluster analysis, grouping both phenotypic variables and patients into clusters. PCA resolved correlated variables (excluding BMI) into independent factors, and the influence of BMI on the components was then explored.ResultsOne thousand and thirty-five women with PCOS were included in the study, with 975 assessed using cluster analysis and PCA. Two main clusters of variables were evident: one characterized by BP, BMI, HOMA-IR, and lipids (triglycerides/cholesterol/LDL) and the second by LH: FSH, androgens, SHBG, and HDL. Three separate patient clusters emerged: cluster A (29.6% of women) showed higher BP, BMI, HOMA-IR, and lipids (triglycerides/cholesterol/LDL) and lower LH: FSH, SHBG, and HDL. Cluster C (43.3%) showed lower BP, BMI, HOMA-IR, triglycerides, testosterone, and FAI and higher LH: FSH, DHEAS, androstenedione, 17-hydroxyprogesterone, SHBG, and HDL. Cluster B (27.1%) was intermediate. Two components aligned with the cluster analysis: principal component (PC) 1, including HOMA-IR, systolic and diastolic BP, triglycerides, LDL, FAI, and SHBG, was positively correlated with BMI (R2= 0.32, p-value < 0.0001) and aligned with cluster A. PC2, influenced by testosterone, LH: FSH, FAI, DHEAS, androstenedione, and 17-hydroxyprogesterone, with loadings in the opposite direction from LDL and cholesterol, aligned with cluster C, with little relationship with BMI (R2= 0.0067, p-value = 0.0107).DiscussionDifferent metabolic and reproductive PCOS subtypes are evident. Androstenedione and 17-hydroxyprogesterone are important in the reproductive phenotype, highlighting the importance of these hormones in diagnosis and subtype identification and emphasizing their significance in understanding PCOS biology as a predominantly hyperandrogenic disorder. BMI influences and exacerbates the metabolic subtype; in the reproductive group and in lean/normal BMI patients, there is little relationship between weight and other PCOS-related characteristics. Accordingly, traditional treatment paradigms cannot be generalized to all women, and these subtypes may ultimately be viewed as separate disorders

Genome-wide association studies (GWAS) relevant to osteoporosis have identified hundreds of loci; however, understanding how these variants influence the phenotype is complicated because most reside in non-coding DNA sequence that serves as transcriptional enhancers and repressors. To advance knowledge on these regulatory elements in osteoclasts (OCs), we performed Micro-C analysis, which informs on the genome topology of these cells and integrated the results with transcriptome and GWAS data to further define loci linked to BMD. Using blood cells isolated from 4 healthy participants aged 31-61 yr, we cultured OC in vitro and generated a Micro-C chromatin conformation capture dataset. We characterized chromatin loops (CLs) in OC from among more than 69 million chromatin interactions identified in the genome. Of the CL identified in OC, >16 000 were unique compared to precursor cells. When sentinel single nucleotide polymorphisms from osteoporosis and bone-related GWAS and those in linkage disequilibrium at r 2 > 0.6 were mapped to CL for OC, 12 588 of these variants were observed within chromatin contact regions. Notable in differential gene ontology enrichment analyses of the topology data for OC and precursors were pathways regulating pluripotency of stem cells, Wnt signaling, nucleotide-binding oligomerization domain (NOD)-like receptor signaling and chemokine signaling. These data, in combination with other 3D genome architecture and epigenetic data (eg, histone modifications and chromatin accessibility), will be useful in modeling to predict genome-wide, which enhancers regulate which genes in OC. This data will therefore also be informative for resolving GWAS hits. In conclusion, we have generated a high-resolution genome topology dataset for human OC and have used this to identify CLs relevant to studies of the genetics of osteoporosis. This data will serve as a powerful resource to inform future functional studies of OC biology.

To date only a fraction of the genetic footprint of thyroid function has been clarified. We report a genome-wide association study meta-analysis of thyroid function in up to 271,040 individuals of European ancestry, including reference range thyrotropin (TSH), free thyroxine (FT4), free and total triiodothyronine (T3), proxies for metabolism (T3/FT4 ratio) as well as dichotomized high and low TSH levels. We revealed 259 independent significant associations for TSH (61% novel), 85 for FT4 (67% novel), and 62 novel signals for the T3 related traits. The loci explained 14.1%, 6.0%, 9.5% and 1.1% of the total variation in TSH, FT4, total T3 and free T3 concentrations, respectively. Genetic correlations indicate that TSH associated loci reflect the thyroid function determined by free T3, whereas the FT4 associations represent the thyroid hormone metabolism. Polygenic risk score and Mendelian randomization analyses showed the effects of genetically determined variation in thyroid function on various clinical outcomes, including cardiovascular risk factors and diseases, autoimmune diseases, and cancer. In conclusion, our results improve the understanding of thyroid hormone physiology and highlight the pleiotropic effects of thyroid function on various diseases.

Polycystic ovary syndrome (PCOS) and its underlying features remain poorly understood. In this genetic and proteomic study, we expand the number of genetic loci from 19 to 29, and identify 31 associated plasma proteins. Many risk-increasing loci were associated with later age at menopause, underscoring the reproductive longevity related to a larger functional ovarian reserve. Hormonal regulation in the aetiology of this condition, through metabolic and reproductive features, was emphasised. The proteomic analysis highlighted perturbations of metabolically-related biology that are typical in women with PCOS. A PCOS polygenic risk score was associated with adverse cardio-metabolic outcomes, with differing contributions of testosterone and BMI in women and men. Finally, while oligo- and anovulatory infertility are characteristic features of PCOS, we observed no impact of PCOS susceptibility on childlessness. We suggest that PCOS susceptibility confers balanced pleiotropic influences on fertility in women, and life-long adverse metabolic consequences in both sexes.

CONTEXT:Autoimmune thyroid disease (AITD) includes Graves disease (GD) and Hashimoto disease (HD), which often run in the same family. AITD etiology is incompletely understood: Genetic factors may account for up to 75% of phenotypic variance, whereas epigenetic effects (including DNA methylation [DNAm]) may contribute to the remaining variance (eg, why some individuals develop GD and others HD). OBJECTIVE:This work aimed to identify differentially methylated positions (DMPs) and differentially methylated regions (DMRs) comparing GD to HD. METHODS:Whole-blood DNAm was measured across the genome using the Infinium MethylationEPIC array in 32 Australian patients with GD and 30 with HD (discovery cohort) and 32 Danish patients with GD and 32 with HD (replication cohort). Linear mixed models were used to test for differences in quantile-normalized β values of DNAm between GD and HD and data were later meta-analyzed. Comb-p software was used to identify DMRs. RESULTS:We identified epigenome-wide significant differences (P < 9E-8) and replicated (P < .05) 2 DMPs between GD and HD (cg06315208 within MDC1 and cg00049440 within KLF9). We identified and replicated a DMR within CUTA (5 CpGs at 6p21.32). We also identified 64 DMPs and 137 DMRs in the meta-analysis. CONCLUSION:Our study reveals differences in DNAm between GD and HD, which may help explain why some people develop GD and others HD and provide a link to environmental risk factors. Additional research is needed to advance understanding of the role of DNAm in AITD and investigate its prognostic and therapeutic potential.

BackgroundType 2 diabetes (T2D) susceptibility is influenced by genetic and environmental factors. Previous findings suggest DNA methylation as a potential mechanism in T2D pathogenesis and progression.MethodsWe profiled DNA methylation in 248 blood samples from participants of European ancestry from 7 twin cohorts using a methylation sequencing platform targeting regulatory genomic regions encompassing 2,048,698 CpG sites.FindingsWe find and replicate 3 previously unreported T2D differentially methylated CpG positions (T2D-DMPs) at FDR 5% in RGL3, NGB and OTX2, and 20 signals at FDR 25%, of which 14 replicated. Integrating genetic variation and T2D-discordant monozygotic twin analyses, we identify both genetic-based and genetic-independent T2D-DMPs. The signals annotate to genes with established GWAS and EWAS links to T2D and its complications, including blood pressure (RGL3) and eye disease (OTX2).InterpretationThe results help to improve our understanding of T2D disease pathogenesis and progression and may provide biomarkers for its complications.FundingFunding acknowledgements for each cohort can be found in the Supplementary Note.

Background Polycystic ovary syndrome (PCOS) is a complex multifactorial disorder with a substantial genetic component. However, the clinical manifestations of PCOS are heterogeneous with notable differences between lean and obese women, implying a different pathophysiology manifesting in differential body mass index (BMI). We performed a meta-analysis of genome-wide association study (GWAS) data from six well-characterised cohorts, using a case–control study design stratified by BMI, aiming to identify genetic variants associated with lean and overweight/obese PCOS subtypes. Results The study comprised 254,588 women (5,937 cases and 248,651 controls) from individual studies performed in Australia, Estonia, Finland, the Netherlands and United States of America, and separated according to three BMI stratifications (lean, overweight and obese). Genome-wide association analyses were performed for each stratification within each cohort, with the data for each BMI group meta-analysed using METAL software. Almost half of the total study population (47%, n = 119,584) were of lean BMI (≤ 25 kg/m 2 ). Two genome-wide significant loci were identified for lean PCOS, led by rs12000707 within DENND1A ( P = 1.55 × 10 –12 ) and rs2228260 within XBP1 ( P = 3.68 × 10 –8 ). One additional locus, LINC02905 , was highlighted as significantly associated with lean PCOS through gene-based analyses ( P = 1.76 × 10 –6 ). There were no significant loci observed for the overweight or obese sub-strata when analysed separately, however, when these strata were combined, an association signal led by rs569675099 within DENND1A reached genome-wide significance ( P = 3.22 × 10 –9 ) and a gene-based association was identified with ERBB4 ( P = 1.59 × 10 –6 ). Nineteen of 28 signals identified in previous GWAS, were replicated with consistent allelic effect in the lean stratum. There were less replicated signals in the overweight and obese groups, and only 4 SNPs were replicated in each of the three BMI strata. Conclusions Genetic variation at the XBP1, LINC02905 and ERBB4 loci were associated with PCOS within unique BMI strata, while DENND1A demonstrated associations across multiple strata, providing evidence of both distinct and shared genetic features between lean and overweight/obese PCOS-affected women. This study demonstrated that PCOS-affected women with contrasting body weight are not only phenotypically distinct but also show variation in genetic architecture; lean PCOS women typically display elevated gonadotrophin ratios, lower insulin resistance, higher androgen levels, including adrenal androgens, and more favourable lipid profiles. Overall, these findings add to the growing body of evidence supporting a genetic basis for PCOS as well as differences in genetic patterns relevant to PCOS BMI-subtype.

Background. Primary hyperparathyroidism (PHPT) and familial hypocalciuric hypercalcaemia (FHH) are common causes of hypercalcaemia. Patients are mostly asymptomatic in the case of FHH and often so in the case of PHPT. In addition, biochemical parameters show considerable overlap, making differential diagnosis difficult. Genetic screening for inactivating variants in the calcium-sensing receptor (CASR) gene that are causative of FHH assists with the diagnosis since such variants are not generally associated with PHPT. However, novel CASR variants must undergo functional assessment before they can be definitively assigned a causative role in FHH. Case Presentations. We describe a 73-year-old female (patient A) who presented with mild parathyroid hormone (PTH)-dependent hypercalcaemia and a history of osteoporosis. Family history revealed that her sister (patient B) had presented a decade earlier with symptoms of PHPT including a history of mild hypercalcaemia and multiple renal calculi, prompting parathyroid surgery. However, a subtotal parathyroidectomy did not resolve her hypercalcaemia long term. On this basis, genetic screening was performed on patient A. This identified a heterozygous variant in the CASR, NM_000388.4:c.T101C: p.Leu34Pro (L34P). Functional analysis showed that the L34P variant was unable to produce mature, dimerized receptor and did not respond to Ca++ ions. Adopting American College of Medical Genetics-based guidelines, the variant was classified as 'Pathogenic (II)'. Patient B was subsequently found to carry the L34P variant heterozygously, confirming a diagnosis of FHH, not PHPT. Conclusion. This study shows the importance of examining patient’s family history in providing clues to the diagnosis in isolated cases of hypercalcaemia. In this case, history of a sister’s unsuccessful parathyroidectomy prompted genetic screening in a patient who might otherwise have undergone inappropriate parathyroid surgery. Screening detected an inactivating CASR variant, firming up a diagnosis of FHH. These studies reaffirm the requirement for functionally assessing novel CASR variants prior to assigning causality to FHH.

Objectives Osteoarthritis (OA) is a joint disease with a heritable component. Genetic loci identified via genome-wide association studies (GWAS) account for an estimated 26.3% of the disease trait variance in humans. Currently, there is no method for predicting the onset or progression of OA. We describe the first use of the Collaborative Cross (CC), a powerful genetic resource, to investigate knee OA in mice, with follow-up targeted multi-omics analysis of homologous regions of the human genome. Methods We histologically screened 275 mice for knee OA and conducted quantitative trait locus (QTL) mapping in the complete cohort (> 8 months) and the younger onset sub-cohort (8–12 months). Multi-omic analysis of human genetic datasets was conducted to investigate significant loci. Results We observed a range of OA phenotypes. QTL mapping identified a genome-wide significant locus on mouse chromosome 19 containing Glis3 , the human equivalent of which has been identified as associated with OA in recent GWAS. Mapping the younger onset sub-cohort identified a genome-wide significant locus on chromosome 17. Multi-omic analysis of the homologous region of the human genome (6p21.32) indicated the presence of pleiotropic effects on the expression of the HLA − DPB2 gene and knee OA development risk, potentially mediated through the effects on DNA methylation. Conclusions The significant associations at the 6p21.32 locus in human datasets highlight the value of the CC model of spontaneous OA that we have developed and lend support for an immune role in the disease. Our results in mice also add to the accumulating evidence of a role for Glis3 in OA.

Background Epidemiological studies have reported a comorbid relationship between migraine and thyroid dysfunction. Methods We investigated the genetic relationship between migraine and thyroid function traits using genome-wide association study (GWAS) data. Results We found a significant genetic correlation ( r g ) with migraine for hypothyroidism ( r g = 0.0608), secondary hypothyroidism ( r g = 0.195), free thyroxine (fT4) ( r g = 0.0772), and hyperthyroidism ( r g = –0.1046), but not thyroid stimulating hormone (TSH). Pairwise GWAS analysis revealed two shared loci with TSH and 11 shared loci with fT4. Cross-trait GWAS meta-analysis of migraine identified novel genome-wide significant loci: 17 with hypothyroidism, one with hyperthyroidism, five with secondary hypothyroidism, eight with TSH, and 15 with fT4. Of the genes at these loci, six ( RERE, TGFB2, APLF, SLC9B1, SGTB, BTBD16; migraine + hypothyroidism), three ( GADD45A, PFDN1, RSPH6A; migraine + TSH), and three ( SSBP3, BRD3, TEF; migraine + fT4) were significant in our gene-based analysis ( p Fisher’s combined P-value < 2.04 × 10 −6 ). In addition, causal analyses suggested a negative causal relationship between migraine and hyperthyroidism ( p = 8.90 × 10 −3 ) and a positive causal relationship between migraine and secondary hypothyroidism ( p = 1.30 × 10 −3 ). Conclusion These findings provide strong evidence for genetic correlation and suggest complex causal relationships between migraine and thyroid traits.

Skull bone mineral density (SK-BMD) provides a suitable trait for the discovery of key genes in bone biology, particularly to intramembranous ossification, not captured at other skeletal sites. We perform a genome-wide association meta-analysis (n ~ 43,800) of SK-BMD, identifying 59 loci, collectively explaining 12.5% of the trait variance. Association signals cluster within gene-sets involved in skeletal development and osteoporosis. Among the four novel loci (ZIC1, PRKAR1A, AZIN1/ATP6V1C1, GLRX3), there are factors implicated in intramembranous ossification and as we show, inherent to craniosynostosis processes. Functional follow-up in zebrafish confirms the importance of ZIC1 on cranial suture patterning. Likewise, we observe abnormal cranial bone initiation that culminates in ectopic sutures and reduced BMD in mosaic atp6v1c1 knockouts. Mosaic prkar1a knockouts present asymmetric bone growth and, conversely, elevated BMD. In light of this evidence linking SK-BMD loci to craniofacial abnormalities, our study provides new insight into the pathophysiology, diagnosis and treatment of skeletal diseases.

There has been a growing interest in the role of the subchondral bone and its resident osteoclasts in the progression of osteoarthritis (OA). A recent genome-wide association study (GWAS) identified 100 independent association signals for OA traits. Most of these signals are led by noncoding variants, suggesting that genetic regulatory effects may drive many of the associations. We have generated a unique human osteoclast-like cell-specific expression quantitative trait locus (eQTL) resource for studying the genetics of bone disease. Considering the potential role of osteoclasts in the pathogenesis of OA, we performed an integrative analysis of this dataset with the recently published OA GWAS results. Summary data-based Mendelian randomization (SMR) and colocalization analyses identified 38 genes with a potential role in OA, including some that have been implicated in Mendelian diseases with joint/skeletal abnormalities, such as BICRA, EIF6, CHST3, and FBN2. Several OA GWAS signals demonstrated colocalization with more than one eQTL peak, including at 19q13.32 (hip OA with BCAM, PRKD2, and BICRA eQTL). We also identified a number of eQTL signals colocalizing with more than one OA trait, including FAM53A, GCAT, HMGN1, MGAT4A, RRP7BP, and TRIOBP. An SMR analysis identified 3 loci with evidence of pleiotropic effects on OA-risk and gene expression: LINC01481, CPNE1, and EIF6. Both CPNE1 and EIF6 are located at 20q11.22, a locus harboring 2 other strong OA candidate genes, GDF5 and UQCC1, suggesting the presence of an OA-risk gene cluster. In summary, we have used our osteoclast-specific eQTL dataset to identify genes potentially involved with the pathogenesis of OA.