👤 G J Myers

Infiltration of T cell acute lymphoblastic leukemia (T-ALL) into the meninges worsens prognosis, underscoring the need to understand mechanisms driving meningeal involvement. Here, we show that T-ALL cells expressing CXCR3 exploit normal T cell function to infiltrate the inflamed meninges. CXCR3 deletion hampered disease progression and extramedullary dissemination by reducing leukemic cell proliferation and migration. Conversely, forced expression of CXCR3 facilitated T-ALL trafficking to the meninges. We identified the ubiquitin-specific protease 7 as a key regulator of CXCR3 protein stability in T-ALL. Furthermore, we discovered elevated levels of CXCL10, a CXCR3 ligand, in the cerebrospinal fluid from patients with T-ALL and leukemia-bearing mice. Our studies demonstrate that meningeal stromal cells, specifically pericytes and fibroblasts, induce CXCL10 expression in response to leukemia and that loss of CXCL10 attenuated T-ALL influx into the meninges. Moreover, we report that leukemia-derived proinflammatory cytokines, TNF-α, IL-27, and IFN-γ, induced CXCL10 in the meningeal stroma. Pharmacological inhibition or deletion of CXCR3 or CXCL10 reduced T-ALL cell migration and adhesion to meningeal stromal cells. Finally, we reveal that CXCR3 and CXCL10 upregulated VLA-4/VCAM-1 signaling, promoting cell-cell adhesion and thus T-ALL retention in the meninges. Our findings highlight the pivotal role of CXCR3-CXCL10 signaling in T-ALL progression and meningeal colonization. Show less

The assessment of serious illness communication (SIC) competence has, to date, primarily utilized tools that are profession-specific and not explicitly designed using competency-based or person-centered frameworks. To address these gaps, we developed and validated a new tool, the Assessment of Clinical Encounters - Communication Tool (ACE-CT). We convened a national panel of interprofessional SIC experts to develop and validate the ACE-CT using a three-phase multi-method approach. Phase 1 focused on item development through review of existing validated tools, and a Bayesian process in which panel members assessed item quality and item-domain correlation. Phase 2 involved item refinement and preliminary validation through stimulated recall interviews using a think-aloud technique. Phase 3 consisted of psychometric analyses for which panel members used the tool to assess video-recorded standardized patient encounters from interprofessional clinicians completing a SIC professional development intervention. In Phase 1, 37 relevant items from previously validated tools were identified, of which 11 items were removed due to redundance. Through the Bayesian process, 14 items were removed and 1 item was generated. Through Phase 2, 2 items were generated, 2 items were combined into 1, and remaining items were refined to optimize measurability and understandability. In Phase 3, reliability was demonstrated through evidence of high internal consistency and moderate reproducibility, both over time and across raters. The tool was found to be responsive and have sound construct validity through evidence of congruence, convergence and credibility. Raters found the tool to be intuitive, easy to complete, and that it accurately captured their perception of the quality of communication observed. The ACE-CT provides a reliable and valid approach to assessing SIC competence among interprofessional clinicians. Through its person-centered orientation, the ACE-CT provides an opportunity to objectively assess elements of SIC that patients and families value. Show less

Association studies have linked many genetic variants to a variety of phenotypes but understanding the biological mechanisms underlying these signals remains a major challenge. Since genes operate within complex networks, statistical interactions between genetic mutations that reflect biological pathways are expected to exist. However, their discovery has been hampered by the vast search space of variant combinations and the multiplicatively small expected effect sizes of interactions. To increase power, we created a test for interaction between single-nucleotide polymorphisms (SNPs) and Show less

Protein truncating variants (PTVs) in To identify high-priority missense variants (HPVs), we applied ‘domain mapping of disease mutations’ for the 637 unique coding In this sample, PTVs and HPVs associated with respectively a 35- and 10-fold increased risk of early onset AD and 17- and 6-fold increased risk of overall AD. The median age at onset (AAO) of PTV- and HPV-carriers was 62 and 64 years, and Our results justify a debate on whether HPV carriers should be considered for clinical counseling. The online version contains supplementary material available at 10.1186/s13024-025-00907-z. Show less

GenIDA is an international patient registry for individuals diagnosed with intellectual disability, autism spectrum disorder, and/or epilepsy, which is based on an online questionnaire that is completed by parent caregivers. In this study, the GenIDA data on Koolen-de Vries syndrome (KdVS) was analyzed illustrating the value of GenIDA and patient/caregiver participation in rare genetic neurodevelopmental disorders (NDDs). Recruitment was done on the GenIDA website from November 2016 to February 2022. Clinical information on individuals with KdVS was extracted for in-depth analysis and for comparison with the GenIDA data of individuals diagnosed with other NDDs. A total of 1417 patients/caregivers across 35 genetic conditions answered to the GenIDA questionnaire, including caregivers of 237 individuals with KdVS. GenIDA findings on KdVS were consistent with the existing literature, and there were no significant differences between individuals with a 17q21.31 microdeletion and those with a pathogenic variant in the GenIDA is a powerful registry to collect and harness valuable data on rare NDDs. The study shows that caregiver-driven data collection is effective in terms of global recruitment and centralization of clinical data. Show less

HIV-specific T cells have diminished effector function and fail to control/eliminate the virus. IL-27, a member of the IL-6/IL-12 cytokine superfamily has been shown to inhibit HIV replication. However, whether or not IL-27 can enhance HIV-specific T cell function is largely unknown. In the present manuscript, we investigated the role of IL-27 signaling in human T cells by evaluating the global transcriptional changes related to the function of HIV-specific T cells. We found that T cells from people living with HIV (PLWH), expressed higher levels of STAT1 leading to enhanced STAT1 activation upon IL-27 stimulation. Observed IL-27 induced transcriptional changes were associated with IFN/STAT1-dependent pathways in CD4 and CD8 T cells. Importantly, IL-27 dependent modulation of T-bet expression promoted IFNγ secretion by TIGIT Show less

Koolen-de Vries syndrome (KdVS) is a genetic condition caused by 17q21.31 microdeletions or pathogenic variants in KANSL1. Affected patients most commonly exhibit some or all of the following: neonatal hypotonia, developmental impairment, facial dysmorphic features, and congenital malformations. Epilepsy occurs in approximately half, often with phenotypes on the epilepsyaphasia spectrum. We describe six children with KdVS found to have continuous spike-wave in sleep (CSWS) on EEG, four of whom were diagnosed with epileptic encephalopathy with CSWS and two with Landau-Kleffner syndrome. When compared with other children with CSWS on EEG, patients with KdVS may present at slightly later ages and with a longer interval between seizure diagnosis and identification of CSWS. There is no clear best treatment for children with CSWS, but two patients in our cohort were trialed on a variation of the ketogenic diet, and both reported clinical improvement. In one of the patients, the response was dramatic, and CSWS recurred when weaning of the ketogenic diet was attempted. Based on our findings, an EEG capturing a prolonged period of sleep should be arranged in any child with KdVS presenting with developmental regression or plateau, particularly if they have a preceding history of seizures. Show less

The paraventricular nucleus of the hypothalamus (PVH) is a heterogeneous collection of neurons that play important roles in modulating feeding and energy expenditure. Abnormal development or ablation of the PVH results in hyperphagic obesity and defects in energy expenditure whereas selective activation of defined PVH neuronal populations can suppress feeding and may promote energy expenditure. Here, we characterize the contribution of calcitonin receptor-expressing PVH neurons (CalcRPVH) to energy balance control. We used Cre-dependent viral tools delivered stereotaxically to the PVH of CalcR2Acre mice to activate, silence, and trace CalcRPVH neurons and determine their contribution to body weight regulation. Immunohistochemistry of fluorescently-labeled CalcRPVH neurons demonstrates that CalcRPVH neurons are largely distinct from several PVH neuronal populations involved in energy homeostasis; these neurons project to regions of the hindbrain that are implicated in energy balance control, including the nucleus of the solitary tract and the parabrachial nucleus. Acute activation of CalcRPVH neurons suppresses feeding without appreciably augmenting energy expenditure, whereas their silencing leads to obesity that may be due in part due to loss of PVH melanocortin-4 receptor signaling. These data show that CalcRPVH neurons are an essential component of energy balance neurocircuitry and their function is important for body weight maintenance. A thorough understanding of the mechanisms by which CalcRPVH neurons modulate energy balance might identify novel therapeutic targets for the treatment and prevention of obesity. Show less

Optimal maternal long-chain PUFA (LCPUFA) status is essential for the developing fetus. The fatty acid desaturase (FADS) genes are involved in the endogenous synthesis of LCPUFA. The minor allele of various FADS SNP have been associated with increased maternal concentrations of the precursors linoleic acid (LA) and α-linolenic acid (ALA), and lower concentrations of arachidonic acid (AA) and DHA. There is limited research on the influence of FADS genotype on cord PUFA status. The current study investigated the influence of maternal and child genetic variation in FADS genotype on cord blood PUFA status in a high fish-eating cohort. Cord blood samples (n 1088) collected from the Seychelles Child Development Study (SCDS) Nutrition Cohort 2 (NC2) were analysed for total serum PUFA. Of those with cord PUFA data available, maternal (n 1062) and child (n 916), FADS1 (rs174537 and rs174561), FADS2 (rs174575), and FADS1-FADS2 (rs3834458) were determined. Regression analysis determined that maternal minor allele homozygosity was associated with lower cord blood concentrations of DHA and the sum of EPA + DHA. Lower cord blood AA concentrations were observed in children who were minor allele homozygous for rs3834458 (β = 0·075; P = 0·037). Children who were minor allele carriers for rs174537, rs174561, rs174575 and rs3834458 had a lower cord blood AA:LA ratio (P < 0·05 for all). Both maternal and child FADS genotype were associated with cord LCPUFA concentrations, and therefore, the influence of FADS genotype was observed despite the high intake of preformed dietary LCPUFA from fish in this population. Show less

Understanding the neural components modulating feeding-related behavior and energy expenditure is crucial to combating obesity and its comorbidities. Neurons within the paraventricular nucleus of the hypothalamus (PVH) are a key component of the satiety response; activation of the PVH decreases feeding and increases energy expenditure, thereby promoting negative energy balance. In contrast, PVH ablation or silencing in both rodents and humans leads to substantial obesity. Recent studies have identified genetically-defined PVH subpopulations that control discrete aspects of energy balance (e.g. oxytocin (OXT), neuronal nitric oxide synthase 1 (NOS1), melanocortin 4-receptor (MC4R), prodynorphin (PDYN)). We previously demonstrated that non-OXT NOS1 Show less

Maternal status of long-chain PUFAs (LC-PUFAs) may be related to fetal growth. Maternal fish consumption exposes the mother to the neurotoxicant methylmercury (MeHg), which, in contrast, may restrict fetal growth. Our aim was to examine relations between maternal LC-PUFA status at 28 wk and birth outcomes (birth weight, length, and head circumference), controlling for MeHg exposure throughout pregnancy, in the Seychelles Child Development Study Nutrition Cohort 2. Our secondary aim was to examine the influence of maternal variation in genes regulating the desaturation of LC-PUFAs [fatty acid desaturase (FADS)] on birth outcomes. From nonfasting blood samples collected at 28 wk of gestation, we measured serum total LC-PUFA concentrations and FADS1 (rs174537, rs174561), FADS1-FADS2rs3834458, and FADS2rs174575 genotypes, with hair total mercury concentrations assessed at delivery. Data were available for n = 1236 mother-child pairs. Associations of maternal LC-PUFAs, MeHg, and FADS genotype with birth outcomes were assessed by multiple linear regression models, adjusting for child sex, gestational age, maternal age, BMI, alcohol use, socioeconomic status, and parity. In our cohort of healthy mothers, neither maternal LC-PUFA status nor MeHg exposure were significant determinants of birth outcomes. However, when compared with major allele homozygotes, mothers who were heterozygous for the minor allele of FADS1 (rs174537 and rs174561, GT compared with TT, β = 0.205, P = 0.03; TC compared with CC, β = 0.203, P = 0.04) and FADS1-FADS2 (rs3834458, Tdel compared with DelDel, β = 0.197, P = 0.04) had infants with a greater head circumference (all P < 0.05). Homozygosity for the minor allele of FADS2 (rs174575) was associated with a greater birth weight (GG compared with CC, β = 0.109, P = 0.04). In our mother-child cohort, neither maternal LC-PUFA status nor MeHg exposure was associated with birth outcomes. The observed associations of variation in maternal FADS genotype with birth outcomes should be confirmed in other populations. Show less

To determine the diagnostic yield of a commercial epilepsy gene panel in adults with chronic epilepsy and accompanying intellectual disability, given that genetic evaluation is often overlooked in this group of patients. This is a cross-sectional study analyzing the results of epilepsy gene panels including up to 185 genes in adult epilepsy patients with intellectual disability, according to Diagnostic and Statistical Manual of Mental Disorders, fifth edition. Patients with acquired structural brain abnormalities or known chromosomal abnormalities were excluded. From approximately 600 patients seen from January 2017 to June 2018 at a single academic epilepsy center, 64 probands and two affected relatives (32 males, mean age = 31 years ± 10) were selected and clinically tested. Fourteen probands (14/64 = 22%; four males, mean age = 32 years ± 10) were found to have pathogenic or likely pathogenic variants in the following genes: SCN1A, GABRB3, UBE3A, KANSL1, SLC2A1, KCNQ2, SLC6A1, HNRNPU, STX1B, SCN2A, PURA, and CHD2. Six variants arose de novo, and the inheritance was not determined in eight. Nine probands (64%) had severe or profound intellectual disability, and five (35%) had autistic features. Eight patients (57%) had a diagnostic change from presumptive clinical diagnosis prior to genetic testing. We were able to demonstrate that a commercial epilepsy gene panel can be an important resource in clinical practice, identifying the etiology in 22% of adults with epilepsy and intellectual disability. The diagnostic yield is similar to previously reported pediatric cohorts. Larger samples would be required to evaluate the more prevalent genotypes among adult epilepsy patients. Show less

KANSL1 haploinsufficiency causes Koolen-de Vries syndrome (KdVS), characterized by dysmorphic features and intellectual disability; amiable personality, congenital malformations and seizures also commonly occur. The epilepsy phenotypic spectrum in KdVS is broad, but most individuals have focal seizures with some having a phenotype resembling the self-limited focal epilepsies of childhood (SFEC). We hypothesized that variants in KANSL1 contribute to pathogenesis of SFEC. We screened KANSL1 for single nucleotide variants in 90 patients with SFEC. We then screened a cohort of 208 patients with two specific SFEC syndromes, childhood epilepsy with centrotemporal spikes (CECTS) and atypical childhood epilepsy with centrotemporal spikes (ACECTS) for KANSL1 variants. The second cohort was also used to evaluate minor allelic variants that appeared overrepresented in the initial cohort. One variant, p.Lys104Thr, was predicted damaging and appeared overrepresented in our 90-patient cohort compared to Genome Aggregation Database (gnomAD) allele frequency (0.217 to 0.116, with no homozygotes in gnomAD). However, there was no difference in p.Lys104Thr allele frequency in the follow-up CECTS/ACECTS cohort and controls. Four rare KANSL1 variants of uncertain significance were identified in the CECTS/ACECTS cohort. Our data do not support a major role for KANSL1 variants in pathogenesis of SFEC. Show less

There is a critical gap in our knowledge of the mechanisms that govern interactions between daily life experiences (e.g., stress) and metabolic diseases, despite evidence that stress can have profound effects on cardiometabolic health. Apolipoprotein A-IV (apoA-IV) is a protein found in chylomicrons (lipoprotein particles that transport lipids throughout the body) where it participates in lipid handling and the regulation of peripheral metabolism. Moreover, apoA-IV is expressed in brain regions that regulate energy balance including the arcuate nucleus. Given that both peripheral and central metabolic processes are important modulators of hypothalamic-pituitary-adrenocortical (HPA) axis activity, the present work tests the hypothesis that apoA-IV activity affects stress responses. As emerging data suggests that apoA-IV actions can vary with background strain, we also explore the strain-dependence of apoA-IV stress regulation. These studies assess HPA axis, metabolic (hyperglycemia), and anxiety-related behavioral responses to psychogenic stress in control (wildtype) and apoA-IV-deficient (KO) mice on either the C57Bl/6J (C57) or 129×1/SvJ (129) background strain. The results indicate that apoA-IV KO increases post-stress corticosterone and anxiety-related behavior specifically in the 129 strain, and increases stress-induced hyperglycemia exclusively in the C57 strain. These data support the hypothesis that apoA-IV is a novel factor that limits stress reactivity in a manner that depends on genetic background. An improved understanding of the complex relationship among lipid homeostasis, stress sensitivity, and genetics is needed to optimize the development of personalized treatments for stress- and metabolism-related diseases. Show less

This study was designed to describe the spectrum of epilepsy phenotypes in Koolen-de Vries syndrome (KdVS), a genetic syndrome involving dysmorphic features, intellectual disability, hypotonia, and congenital malformations, that occurs secondary to 17q21.31 microdeletions and heterozygous mutations in KANSL1. We were invited to attend a large gathering of individuals with KdVS and their families. While there, we recruited individuals with KdVS and seizures, and performed thorough phenotyping. Additional subjects were included who approached us after the family support group brought attention to our research via social media. Inclusion criteria were genetic testing results demonstrating 17q21.31 deletion or KANSL1 mutation, and at least one seizure. Thirty-one individuals were studied, aged 2-35 years. Median age at seizure onset was 3.5 years, and 9 of 22 had refractory seizures 2 years after onset. Focal impaired awareness seizures were the most frequent seizure type occurring in 20 of 31, usually with prominent autonomic features. Twenty-one patients had prolonged seizures and, at times, refractory status epilepticus. Electroencephalography (EEG) showed focal/multifocal epileptiform discharges in 20 of 26. MRI studies of 13 patients were reviewed, and all had structural anomalies. Corpus callosum dysgenesis, abnormal hippocampi, and dilated ventricles were the most common, although periventricular nodular heterotopia, focal cortical dysplasia, abnormal sulcation, and brainstem and cerebellum abnormalities were also observed. One patient underwent epilepsy surgery for a lesion that proved to be an angiocentric glioma. The typical epilepsy phenotype of KdVS involves childhood-onset focal seizures that are prolonged and have prominent autonomic features. Multifocal epileptiform discharges are the typical EEG pattern. Structural brain abnormalities may be universal, including signs of abnormal neuroblast migration and abnormal axonal guidance. Epilepsy surgery should be undertaken with care given the widespread neuroanatomic abnormalities; however, tumors are a rare, yet important, occurrence. Show less

The liver X receptors (LXRs, NR1H2 and NR1H3) and peroxisome proliferator-activated receptor gamma (PPARG, NR1C3) nuclear receptor transcription factors (TFs) are master regulators of energy homeostasis. Intriguingly, recent studies suggest that these metabolic regulators also impact tumor cell proliferation. However, a comprehensive temporal molecular characterization of the LXR and PPARG gene regulatory responses in tumor cells is still lacking. To better define the underlying molecular processes governing the genetic control of cellular growth in response to extracellular metabolic signals, we performed a comprehensive, genome-wide characterization of the temporal regulatory cascades mediated by LXR and PPARG signaling in HT29 colorectal cancer cells. For this analysis, we applied a multi-tiered approach that incorporated cellular phenotypic assays, gene expression profiles, chromatin state dynamics, and nuclear receptor binding patterns. Our results illustrate that the activation of both nuclear receptors inhibited cell proliferation and further decreased glutathione levels, consistent with increased cellular oxidative stress. Despite a common metabolic reprogramming, the gene regulatory network programs initiated by these nuclear receptors were widely distinct. PPARG generated a rapid and short-term response while maintaining a gene activator role. By contrast, LXR signaling was prolonged, with initial, predominantly activating functions that transitioned to repressive gene regulatory activities at late time points. Through the use of a multi-tiered strategy that integrated various genomic datasets, our data illustrate that distinct gene regulatory programs elicit common phenotypic effects, highlighting the complexity of the genome. These results further provide a detailed molecular map of metabolic reprogramming in cancer cells through LXR and PPARG activation. As ligand-inducible TFs, these nuclear receptors can potentially serve as attractive therapeutic targets for the treatment of various cancers. Show less

Long-chain n-6 and n-3 PUFA (LC-PUFA), arachidonic acid (AA) (20:4n-6) and DHA (22:6n-3), are critical for optimal brain development. These fatty acids can be consumed directly from the diet, or synthesized endogenously from precursor PUFA by Δ-5 (encoded by FADS1) and Δ-6 desaturases (encoded by FADS2). The aim of this study was to determine the potential importance of maternal genetic variability in FADS1 and FADS2 genes to maternal LC-PUFA status and infant neurodevelopment in populations with high fish intakes. The Nutrition Cohorts 1 (NC1) and 2 (NC2) are longitudinal observational mother-child cohorts in the Republic of Seychelles. Maternal serum LC-PUFA was measured at 28 weeks gestation and genotyping for rs174537 (FADS1), rs174561 (FADS1), rs3834458 (FADS1-FADS2) and rs174575 (FADS2) was performed in both cohorts. The children completed the Bayley Scales of Infant Development II (BSID-II) at 30 months in NC1 and at 20 months in NC2. Complete data were available for 221 and 1310 mothers from NC1 and NC2 respectively. With increasing number of rs3834458 minor alleles, maternal concentrations of AA were significantly decreased (NC1 p=0.004; NC2 p<0.001) and precursor:product ratios for linoleic acid (LA) (18:2n-6)-to-AA (NC1 p<0.001; NC2 p<0.001) and α-linolenic acid (ALA) (18:3n-3)-to-DHA were increased (NC2 p=0.028). There were no significant associations between maternal FADS genotype and BSID-II scores in either cohort. A trend for improved PDI was found among infants born to mothers with the minor rs3834458 allele.In these high fish-eating cohorts, genetic variability in FADS genes was associated with maternal AA status measured in serum and a subtle association of the FADS genotype was found with neurodevelopment. Show less

Here, we identify coiled-coil domain-containing protein 13 (Ccdc13) in a genome-wide RNA interference screen for regulators of genome stability. We establish that Ccdc13 is a newly identified centriolar satellite protein that interacts with PCM1, Cep290 and pericentrin and prevents the accumulation of DNA damage during mitotic transit. Depletion of Ccdc13 results in the loss of microtubule organisation in a manner similar to PCM1 and Cep290 depletion, although Ccdc13 is not required for satellite integrity. We show that microtubule regrowth is enhanced in Ccdc13-depleted cells, but slowed in cells that overexpress Ccdc13. Furthermore, in serum-starved cells, Ccdc13 localises to the basal body, is required for primary cilia formation and promotes the localisation of the ciliopathy protein BBS4 to both centriolar satellites and cilia. These data highlight the emerging link between DNA damage response factors, centriolar and peri-centriolar satellites and cilia-associated proteins and implicate Ccdc13 as a centriolar satellite protein that functions to promote both genome stability and cilia formation. Show less

The G-protein linked signaling system (GPLS) comprises a large number of G-proteins, G protein-coupled receptors (GPCRs), GPCR ligands, and downstream effector molecules. G-proteins interact with both GPCRs and downstream effectors such as cyclic adenosine monophosphate (cAMP), phosphatidylinositols, and ion channels. The GPLS is implicated in the pathophysiology and pharmacology of both major depressive disorder (MDD) and bipolar disorder (BPD). This study evaluated whether GPLS is altered at the transcript level. The gene expression in the dorsolateral prefrontal (DLPFC) and anterior cingulate (ACC) were compared from MDD, BPD, and control subjects using Affymetrix Gene Chips and real time quantitative PCR. High quality brain tissue was used in the study to control for confounding effects of agonal events, tissue pH, RNA integrity, gender, and age. GPLS signaling transcripts were altered especially in the ACC of BPD and MDD subjects. Transcript levels of molecules which repress cAMP activity were increased in BPD and decreased in MDD. Two orphan GPCRs, GPRC5B and GPR37, showed significantly decreased expression levels in MDD, and significantly increased expression levels in BPD. Our results suggest opposite changes in BPD and MDD in the GPLS, "activated" cAMP signaling activity in BPD and "blunted" cAMP signaling activity in MDD. GPRC5B and GPR37 both appear to have behavioral effects, and are also candidate genes for neurodegenerative disorders. In the context of the opposite changes observed in BPD and MDD, these GPCRs warrant further study of their brain effects. Show less

Circulatory metabolites are important biomarkers for many diseases, especially metabolic disorders. The biological mechanism regulating circulatory levels of metabolites remains incompletely understood. Focusing on the liver as the central organ controlling metabolic homeostasis, we investigated the potential function of nine polymorphisms associated with serum metabolomic traits in a recent GWAS. The mRNA levels of the associated genes were measured by real-time PCR and correlated with genotypes in normal liver tissue (n=42). Genotype and mRNA data were also correlated with total hepatic lipid content (HLC). Our findings were also compared with the previously published gene expression quantitative traits loci (eQTL) data in the liver. We found that seven out of nine genes were highly expressed in hepatic tissue, while expression of four genes was significantly or marginally associated with genotypes (SPTLC3 vs rs168622, P=.002; ACADS vs rs2014355, P=.016; PLEKHH1 vs rs7156144, P=.076; ACADL vs rs2286963, P=.068). The SNP rs168622 at the SPTLC3 locus was also significantly correlated with HLC (P=.02). HLC was significantly correlated with FADS1 (r=-0.45; P=.003) and ETFDH (r=0.33; P=.037) expression. When compared with published eQTL data, SNPs in SPTLC3, ACADS, ELOVL2 and FADS1 were also in strong linkage disequilibrium (R(2)≥0.41, D'≥0.96) with eQTLs significantly affecting expression of these genes (P≤1.74×10(-5)). Our study suggests that genetic variants affecting serum metabolites levels may play a functional role in the liver. This may help elucidate the mechanism by which genetic variants are involved in metabolic diseases. Show less

Obesity is globally prevalent and highly heritable, but its underlying genetic factors remain largely elusive. To identify genetic loci for obesity susceptibility, we examined associations between body mass index and ∼ 2.8 million SNPs in up to 123,865 individuals with targeted follow up of 42 SNPs in up to 125,931 additional individuals. We confirmed 14 known obesity susceptibility loci and identified 18 new loci associated with body mass index (P < 5 × 10⁻⁸), one of which includes a copy number variant near GPRC5B. Some loci (at MC4R, POMC, SH2B1 and BDNF) map near key hypothalamic regulators of energy balance, and one of these loci is near GIPR, an incretin receptor. Furthermore, genes in other newly associated loci may provide new insights into human body weight regulation. Show less

Heterochromatin protein-1 (HP1) plays an essential role in both the assembly of higher-order chromatin structure and epigenetic inheritance. The C-terminal chromo shadow domain (CSD) of HP1 is responsible for homodimerization and interaction with a number of chromatin-associated nonhistone proteins, including EMSY, which is a BRCA2-interacting protein that has been implicated in the development of breast and ovarian cancer. We have determined the crystal structure of the HP1beta CSD in complex with the N-terminal domain of EMSY at 1.8 A resolution. Surprisingly, the structure reveals that EMSY is bound by two HP1 CSD homodimers, and the binding sequences differ from the consensus HP1 binding motif PXVXL. This structural information expands our understanding of HP1 binding specificity and provides insights into interactions between HP1 homodimers that are likely to be important for heterochromatin formation. Show less

Familial combined hyperlipidemia (FCHL), the most common familial dyslipidemia, is implicated in up to 20% of cases of premature coronary heart disease. Although underlying mutations for FCHL have yet to be identified, several candidate genes/regions have been identified. A positive linkage to chromosome 1q markers has been reported, with the highest lod score of 5.93 occurring at a location between D1S104 and D1S1677. Using the same diagnostic criteria, the Family Heart Study (FHS) has defined 71 FCHL families, comprising 170 cases, for a total of 137 possible affected sibling pairs. The FCHL criteria require elevation in serum low density lipoprotein cholesterol and triglyceride levels within the family, with at least 2 affected first-degree relatives. Markers D1S104 and D1S1677 were typed, and significant allele sharing was found in FCHL sibships (multipoint lod score with use of the model from the Finnish study was 2.52, and multipoint nonparametric score was 2.48; P=0.007), replicating linkage in this chromosome 1 region. In addition, previously reported linkage of FCHL to apolipoprotein A-I/C-III/A-IV has been investigated in FHS families. FHS results revealed positive but nonsignificant allele sharing among FCHL sibships with apolipoprotein A-I/C-III/A-IV by use of marker D11S4127 (nonparametric linkage score 1.11, P=0.13). Two-locus analyses of D1S104 and D11S4127 suggested possible heterogeneity rather than epistasis, with a maximum 2-locus lod score of 3.05. A nonparametric 2-locus analysis revealed significant improvement in the 2-locus versus single-locus scores. Finally, no linkage was found with markers near the lipoprotein lipase gene region. Show less

Among the epilepsies, the progressive myoclonus epilepsies (PMEs) form a heterogeneous group of rare diseases characterized by myoclonus, epilepsy, and progressive neurologic deterioration, particularly dementia and ataxia. The success of the Human Genome Project and the fact that most PMEs are inherited through a mendelian or mitochondrial mode have resulted in important advances in the definition of the molecular basis of PME. The gene defects for the most common forms of PME (Unverricht-Lundborg disease, the neuronal ceroid lipofuscinoses, Lafora disease, type I sialidosis, and myoclonus epilepsy with ragged-red fibers) have been either identified or mapped to specific chromosome sites. Unverricht-Lundborg disease has been shown to be caused by mutations in the gene that codes for cystatin B, an inhibitor of cysteine protease. The most common mutation in Unverricht-Lundborg disease is an expansion of a dodecamer repeat located in a noncoding region upstream of the transcription start site of the cystatin B gene, making it the first human disease associated with instability of a dodecamer repeat. Juvenile neuronal ceroid lipofuscinosis is caused by mutations in the CLN3 gene, a gene of unknown function that encodes a 438-amino-acid protein of possible mitochondrial location. Other forms of neuronal ceroid lipofuscinosis that occur as PME and Lafora disease have been mapped by means of linkage analysis, but the corresponding gene defects remain unknown. Sialidosis has been shown to be caused by mutations in the sialidase gene, and myoclonus epilepsy with ragged-red fibers is well known to be caused by mutations in the mitochondrial gene that codes for tRNA(Lys). How the different PME gene defects described produce the various PME phenotypes, including epileptic seizures, remains unknown. The development of animal models that bear these mutations is needed to increase our knowledge of the basic mechanisms involved in the PMEs. This knowledge should lead to the development of new and effective forms of therapy, which are especially lacking for the PMEs. Show less