👤 J D Sharp

Contact sports, including rugby union, are associated with higher rates of neurodegenerative dementia, due to various underlying pathologies such as Alzheimer's disease (AD) and chronic traumatic encephalopathy (CTE). New ultrasensitive multiplexed immunoassays may clarify disease mechanisms after repetitive head impacts (RHI) and traumatic brain injury, potentially aiding risk-stratification, early diagnosis and dementia treatment. Midlife participants in the ABHC cohort underwent plasma biomarker quantification (NULISA - NUcleic acid Linked Immuno-Sandwich Assay; n=124 markers), 3T MRI, trauma exposure ascertainment and phenotyping. Regressions quantified exposure-specific protein expression, relationship to trauma (including position) and brain atrophy, using cluster analysis to test correlates of traumatic encephalopathy syndrome (TES). 197 former elite rugby players and 33 controls were assessed. 24 (12.2%) met criteria for TES but none had dementia. Ex-players returned reduced plasma glial fibrillary acidic protein (GFAP), kallikrein-6 (KLK6) and synaptosomal-associated protein 25 (SNAP25). Ex-forwards specifically showed reduced plasma beta-site amyloid precursor protein cleaving enzyme 1 (BACE1), amyloid beta-38 (Aβ38), and increased phospho-tau Ex-players showed distinctive plasma biomarker changes, more prominently in ex-forwards, possibly reflecting greater RHI exposure. Plasma KLK6, an endothelial serine protease, was reduced across the ex-player group, with potential diagnostic or prognostic utility in future. Reduced GFAP and SNAP25 in ex-forwards has an uncertain basis, while elevated p-tau- Show less

Dietary guidelines recommend replacing saturated fatty acid with unsaturated fats, particularly polyunsaturated fatty acids. Cohort studies do not suggest a clear benefit of higher intake of polyunsaturated fatty acids but, in contrast, higher circulating linoleic acid (LA) levels-reflective of dietary LA intake, are associated with a reduced risk of type 2 diabetes. However, genetic variants in the fatty acid desaturase 1 gene (FADS1) may influence individual responses to plant-based fats. We explored whether FADS1 variants influence the relationships of LA and α-linolenic acid (ALA) intakes and nut consumption with plasma phospholipid fatty acid profiles and type 2 diabetes risk in a large-scale cohort study and a randomized controlled trial. In the EPIC-InterAct case-cohort (7,498 type 2 diabetes cases, 10,087 subcohort participants), we investigated interactions of dietary and plasma phospholipid fatty acids and nut consumption with FADS1 rs174547 in relation to incident type 2 diabetes using weighted Cox regression. In PREDIMED (492 participants in the Mediterranean Diet + Nuts intervention group, 436 participants in the control group), we compared changes in plasma phospholipid FAs from baseline to year 1. In EPIC-InterAct and PREDIMED, nut consumption was positively associated with LA plasma levels and inversely with arachidonic acid, the latter becoming stronger with increasing number of the minor rs174547 C allele (p interaction EPIC-InterAct: 0.030, PREDIMED: 0.003). Although the inverse association of nut consumption with diabetes seemed stronger in participants with rs174547 CC-genotype (HR: 0.73, 95% CI: 0.54-1.00) compared with CT (0.94, 0.81-1.10) or TT (0.90, 0.78-1.05) in EPIC-InterAct, this interaction was not statistically significant. FADS1 variation modified the effect of nut consumption on circulating FAs. We did not observe clear evidence that it modified the association between nut consumption and type 2 diabetes risk. Show less

To execute a large-scale, decentralized, clinical-grade whole exome sequencing study, coined Tapestry, for clinical practice, research discovery, and genomic education. Between July 1, 2020, and May 31, 2024, we invited 1,287,608 adult Mayo Clinic patients to participate in Tapestry. Of those contacted, 114,673 patients were consented and 98,222 (65.2% women) are currently enrolled: 62,495 (63.6%) were recruited from Minnesota-, 18,353 (18.7%) from Florida- and 17,374 (17.7%) from Arizona-based practices. Saliva from participants was used to extract DNA, and whole exome sequencing plus ∼300,000 single nucleotide polymorphisms (ie, Exome+ assay) were sequenced by a clinical lab. Results for the Centers for Disease Control and Prevention Tier 1 genes (eg, hereditary breast, ovarian cancer syndrome: BRCA1/2; Lynch syndrome: MLH1, MSH2, MSH6, PMS2, and EPCAM; and familial hypercholesterolemia: APOB, LDLR, PCSK9, and LDLRAP1) were interpreted and entered into the electronic health record. The median age of participants was 59.1 years and ∼11% were from racial/ethnic groups under-represented in research. One thousand eight hundred nineteen (1.9%) participants had actionable pathogenic or likely pathogenic variants (50.0% BRCA1/2, 28.4% familial hypercholesterolemia, and 22.2% Lynch syndrome). Positive results were communicated by genetic counselors who educated patients and providers. Thus far, 62,758 patients' Exome+ assays are stored for research, and the Tapestry Data Access Committee has received 118 requests from investigators, of which 82 have been approved, resulting in the delivery of 1,117,410 Exome+ assays to researchers. A large, decentralized, clinical Exome+ assay study in a tertiary medical center detects actionable germline variants, educates patients as well as providers, and offers access to big data for discovery that advances human health. clinicaltrials.gov Identifier: NCT05212428. Show less

Childhood cancer survivors (CCS) exhibit significantly increased chronic diseases and premature death. Abnormalities in DNA methylation are associated with development of chronic diseases and reduced life expectancy. We investigated the hypothesis that anti-cancer treatments are associated with long-term DNA methylation changes that could be key drivers of adverse late health effects. Genome-wide DNA methylation was assessed using MethylationEPIC arrays in paired samples (before/after therapy) from 32 childhood cancer patients. Separately, methylation was determined in 32 samples from different adult CCS (mean 22-years post-diagnosis) and compared with cancer-free controls (n = 284). Widespread DNA methylation changes were identified post-treatment in childhood cancer patients, including 146 differentially methylated regions (DMRs), which were consistently altered in the 32 post-treatment samples. Analysis of adult CCS identified matching methylation changes at 107/146 of the DMRs, suggesting potential long-term retention of post-therapy changes. Adult survivors also exhibited epigenetic age acceleration, independent of DMR methylation. Furthermore, altered methylation at the DUSP6 DMR was significantly associated with early mortality, suggesting altered methylation may be prognostic for some late adverse health effects in CCS. These novel methylation changes could serve as biomarkers for assessing normal cell toxicity in ongoing treatments and predicting long-term health outcomes in CCS. Show less

Higher plasma vitamin C levels are associated with lower type 2 diabetes risk, but whether this association is causal is uncertain. To investigate this, we studied the association of genetically predicted plasma vitamin C with type 2 diabetes. We conducted genome-wide association studies of plasma vitamin C among 52,018 individuals of European ancestry to discover novel genetic variants. We performed Mendelian randomization analyses to estimate the association of genetically predicted differences in plasma vitamin C with type 2 diabetes in up to 80,983 case participants and 842,909 noncase participants. We compared this estimate with the observational association between plasma vitamin C and incident type 2 diabetes, including 8,133 case participants and 11,073 noncase participants. We identified 11 genomic regions associated with plasma vitamin C ( These findings indicate discordance between biochemically measured and genetically predicted plasma vitamin C levels in the association with type 2 diabetes among European populations. The null Mendelian randomization findings provide no strong evidence to suggest the use of vitamin C supplementation for type 2 diabetes prevention. Show less

CD38, a druggable ectoenzyme, is involved in the generation of adenosine, which is implicated in tumour immune evasion. Its expression and role in prostate tumour-infiltrating immune cells (TIICs) have not been elucidated. To characterise CD38 expression on prostate cancer (PC) epithelial cells and TIICs, and to associate this expression with clinical outcomes. RNAseq from 159 patients with metastatic castration-resistant prostate cancer (mCRPC) in the International Stand Up To Cancer/Prostate Cancer Foundation (SU2C/PCF) cohort and 171 mCRPC samples taken from 63 patients in the Fred Hutchinson Cancer Research Centre cohort were analysed. CD38 expression was immunohistochemically scored by a validated assay on 51 castration-resistant PC (CRPC) and matching, same-patient castration-sensitive PC (CSPC) biopsies obtained between 2016 and 2018, and was associated with retrospectively collected clinical data. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: mCRPC transcriptomes were analysed for associations between CD38 expression and gene expression signatures. Multiplex immunofluorescence determined CD38 expression in PC biopsies. Differences in CD38 CD38 mRNA expression in mCRPC was most significantly associated with upregulated immune signalling pathways. CD38 mRNA expression was associated with interleukin (IL)-12, IL-23, and IL-27 signalling signatures as well as immunosuppressive adenosine signalling and T cell exhaustion signatures. CD38 protein was frequently expressed on phenotypically diverse TIICs including B cells and myeloid cells, but largely absent from tumour epithelial cells. CD38 CD38 CD38 is expressed on the surface of white blood cells surrounding PC cells. These cells may impact PC growth and treatment resistance. Patients with PC with more CD38-expressing white blood cells are more likely to die earlier. Show less

Liver iron excess is observed in several chronic liver diseases and is associated with the development of hepatocellular carcinoma (HCC). However, apart from oxidative stress, other cellular mechanisms by which excess iron may mediate/increase HCC predisposition/progression are not known. HCC pathology involves epithelial to mesenchymal transition (EMT), the basis of cancer phenotype acquisition. Here, the effect of excess iron (holo-transferrin 0-2 g/L for 24 and 48 h) on EMT biomarkers in the liver-derived HepG2 cells was investigated. Holo-transferrin substantially increased intracellular iron. Unexpectedly, mRNA and protein expression of the epithelial marker E-cadherin either remained unaltered or increased. The mRNA and protein levels of metastasis marker N-cadherin and mesenchymal marker vimentin increased significantly. While the mRNA expression of EMT transcription factors SNAI1 and SNAI2 increased and decreased, respectively after 24 h, both factors increased after 48 h. The mRNA expression of TGF-β (EMT-inducer) showed no significant alterations. In conclusion, data showed direct link between iron and EMT. Iron elevated mesenchymal and metastatic biomarkers in HepG2 cells without concomitant decrement in the epithelial marker E-cadherin and altered the expression of the key EMT-mediating transcription factors. Such studies can help identify molecular targets to devise iron-related adjunctive therapies to ameliorate HCC pathophysiology. Show less

The melanocortin 4 receptor (MC4R) is a G protein-coupled receptor whose disruption causes obesity. We functionally characterized 61 MC4R variants identified in 0.5 million people from UK Biobank and examined their associations with body mass index (BMI) and obesity-related cardiometabolic diseases. We found that the maximal efficacy of β-arrestin recruitment to MC4R, rather than canonical Gα Show less

Pharmacological enhancers of lipoprotein lipase (LPL) are in preclinical or early clinical development for cardiovascular prevention. Studying whether these agents will reduce cardiovascular events or diabetes risk when added to existing lipid-lowering drugs would require large outcome trials. Human genetics studies can help prioritize or deprioritize these resource-demanding endeavors. To investigate the independent and combined associations of genetically determined differences in LPL-mediated lipolysis and low-density lipoprotein cholesterol (LDL-C) metabolism with risk of coronary disease and diabetes. In this genetic association study, individual-level genetic data from 392 220 participants from 2 population-based cohort studies and 1 case-cohort study conducted in Europe were included. Data were collected from January 1991 to July 2018, and data were analyzed from July 2014 to July 2018. Six conditionally independent triglyceride-lowering alleles in LPL, the p.Glu40Lys variant in ANGPTL4, rare loss-of-function variants in ANGPTL3, and LDL-C-lowering polymorphisms at 58 independent genomic regions, including HMGCR, NPC1L1, and PCSK9. Odds ratio for coronary artery disease and type 2 diabetes. Of the 392 220 participants included, 211 915 (54.0%) were female, and the mean (SD) age was 57 (8) years. Triglyceride-lowering alleles in LPL were associated with protection from coronary disease (approximately 40% lower odds per SD of genetically lower triglycerides) and type 2 diabetes (approximately 30% lower odds) in people above or below the median of the population distribution of LDL-C-lowering alleles at 58 independent genomic regions, HMGCR, NPC1L1, or PCSK9. Associations with lower risk were consistent in quintiles of the distribution of LDL-C-lowering alleles and 2 × 2 factorial genetic analyses. The 40Lys variant in ANGPTL4 was associated with protection from coronary disease and type 2 diabetes in groups with genetically higher or lower LDL-C. For a genetic difference of 0.23 SDs in LDL-C, ANGPTL3 loss-of-function variants, which also have beneficial associations with LPL lipolysis, were associated with greater protection against coronary disease than other LDL-C-lowering genetic mechanisms (ANGPTL3 loss-of-function variants: odds ratio, 0.66; 95% CI, 0.52-0.83; 58 LDL-C-lowering variants: odds ratio, 0.90; 95% CI, 0.89-0.91; P for heterogeneity = .009). Triglyceride-lowering alleles in the LPL pathway are associated with lower risk of coronary disease and type 2 diabetes independently of LDL-C-lowering genetic mechanisms. These findings provide human genetics evidence to support the development of agents that enhance LPL-mediated lipolysis for further clinical benefit in addition to LDL-C-lowering therapy. Show less

Deregulation of the cyclin-dependent kinases (CDKs) has been implicated in the pathogenesis of multiple cancer types. Consequently, CDKs have garnered intense interest as therapeutic targets for the treatment of cancer. We describe herein the molecular and cellular effects of CCT068127, a novel inhibitor of CDK2 and CDK9. Optimized from the purine template of seliciclib, CCT068127 exhibits greater potency and selectivity against purified CDK2 and CDK9 and superior antiproliferative activity against human colon cancer and melanoma cell lines. X-ray crystallography studies reveal that hydrogen bonding with the DFG motif of CDK2 is the likely mechanism of greater enzymatic potency. Commensurate with inhibition of CDK activity, CCT068127 treatment results in decreased retinoblastoma protein (RB) phosphorylation, reduced phosphorylation of RNA polymerase II, and induction of cell cycle arrest and apoptosis. The transcriptional signature of CCT068127 shows greatest similarity to other small-molecule CDK and also HDAC inhibitors. CCT068127 caused a dramatic loss in expression of DUSP6 phosphatase, alongside elevated ERK phosphorylation and activation of MAPK pathway target genes. MCL1 protein levels are rapidly decreased by CCT068127 treatment and this associates with synergistic antiproliferative activity after combined treatment with CCT068127 and ABT263, a BCL2 family inhibitor. These findings support the rational combination of this series of CDK2/9 inhibitors and BCL2 family inhibitors for the treatment of human cancer. Show less

HIV lipodystrophy is characterised by abnormal adipose tissue distribution and metabolism, as a result of altered adipocyte function and gene expression. The protease inhibitor ritonavir is associated with the development of lipodystrophy. Quantifying changes in adipogenic gene expression in the presence of ritonavir may help to identify therapeutic targets for HIV lipodystrophy. Affymetrix Mouse Genome 430 2.0 oligonucleotide microarray was used to investigate gene expression in 3T3-L1 adipocytes treated with 20 µmol/l ritonavir or vehicle control (ethanol). Pparg, Adipoq, Retn and Il6 expression were validated by real time RT-PCR. Transcriptional signalling through PPAR-γ was investigated using a DNA-binding ELISA. Changes in adipocyte function were investigated through secreted adiponectin quantification using ELISA and Oil Red O staining for triglyceride storage. Expression of 389 genes was altered by more than 5-fold in the presence of ritonavir (all P < 0.001). Gene ontology analysis revealed down-regulation of genes responsible for adipocyte triglyceride accumulation including complement factor D (Cfd; 238.42-fold), Cidec (73.75-fold) and Pparg (5.63-fold). Glucose transport genes were also down-regulated including Adipoq (24.42-fold) and Glut4 (13.36-fold), while Il6 was up-regulated (10.39-fold). PPAR-γ regulatory genes Cebpa (11.33-fold) and liver-X-receptor α (Nr1h3) were down-regulated. Changes in Pparg, Adipoq and Il6 were confirmed by RT-PCR. PPAR-γ binding to its nuclear consensus site, adiponectin secretion and triglyceride accumulation were all reduced by ritonavir. Ritonavir had a significant effect on expression of genes involved in adipocyte differentiation, lipid accumulation and glucose metabolism. Down-regulation of Pparg may be mediated by changes in Cebpa, Lcn2 and Nr1h3. Show less

Since RNA expression differences have been reported in autism spectrum disorder (ASD) for blood and brain, and differential alternative splicing (DAS) has been reported in ASD brains, we determined if there was DAS in blood mRNA of ASD subjects compared to typically developing (TD) controls, as well as in ASD subgroups related to cerebral volume. RNA from blood was processed on whole genome exon arrays for 2-4-year-old ASD and TD boys. An ANCOVA with age and batch as covariates was used to predict DAS for ALL ASD (n=30), ASD with normal total cerebral volumes (NTCV), and ASD with large total cerebral volumes (LTCV) compared to TD controls (n=20). A total of 53 genes were predicted to have DAS for ALL ASD versus TD, 169 genes for ASD_NTCV versus TD, 1 gene for ASD_LTCV versus TD, and 27 genes for ASD_LTCV versus ASD_NTCV. These differences were significant at P <0.05 after false discovery rate corrections for multiple comparisons (FDR <5% false positives). A number of the genes predicted to have DAS in ASD are known to regulate DAS (SFPQ, SRPK1, SRSF11, SRSF2IP, FUS, LSM14A). In addition, a number of genes with predicted DAS are involved in pathways implicated in previous ASD studies, such as ROS monocyte/macrophage, Natural Killer Cell, mTOR, and NGF signaling. The only pathways significant after multiple comparison corrections (FDR <0.05) were the Nrf2-mediated reactive oxygen species (ROS) oxidative response (superoxide dismutase 2, catalase, peroxiredoxin 1, PIK3C3, DNAJC17, microsomal glutathione S-transferase 3) and superoxide radical degradation (SOD2, CAT). These data support differences in alternative splicing of mRNA in blood of ASD subjects compared to TD controls that differ related to head size. The findings are preliminary, need to be replicated in independent cohorts, and predicted alternative splicing differences need to be confirmed using direct analytical methods. Show less

To infer the causal association between childhood BMI and age at menarche, we performed a mendelian randomisation analysis using twelve established "BMI-increasing" genetic variants as an instrumental variable (IV) for higher BMI. In 8,156 women of European descent from the EPIC-Norfolk cohort, height was measured at age 39-77 years; age at menarche was self-recalled, as was body weight at age 20 years, and BMI at 20 was calculated as a proxy for childhood BMI. DNA was genotyped for twelve BMI-associated common variants (in/near FTO, MC4R, TMEM18, GNPDA2, KCTD15, NEGR1, BDNF, ETV5, MTCH2, SEC16B, FAIM2 and SH2B1), and for each individual a "BMI-increasing-allele-score" was calculated by summing the number of BMI-increasing alleles across all 12 loci. Using this BMI-increasing-allele-score as an instrumental variable for BMI, each 1 kg/m(2) increase in childhood BMI was predicted to result in a 6.5% (95% CI: 4.6-8.5%) higher absolute risk of early menarche (before age 12 years). While mendelian randomisation analysis is dependent on a number of assumptions, our findings support a causal effect of BMI on early menarche and suggests that increasing prevalence of childhood obesity will lead to similar trends in the prevalence of early menarche. Show less

OBJECTIVE Recent genome-wide association studies have revealed loci associated with glucose and insulin-related traits. We aimed to characterize 19 such loci using detailed measures of insulin processing, secretion, and sensitivity to help elucidate their role in regulation of glucose control, insulin secretion and/or action. RESEARCH DESIGN AND METHODS We investigated associations of loci identified by the Meta-Analyses of Glucose and Insulin-related traits Consortium (MAGIC) with circulating proinsulin, measures of insulin secretion and sensitivity from oral glucose tolerance tests (OGTTs), euglycemic clamps, insulin suppression tests, or frequently sampled intravenous glucose tolerance tests in nondiabetic humans (n = 29,084). RESULTS The glucose-raising allele in MADD was associated with abnormal insulin processing (a dramatic effect on higher proinsulin levels, but no association with insulinogenic index) at extremely persuasive levels of statistical significance (P = 2.1 x 10(-71)). Defects in insulin processing and insulin secretion were seen in glucose-raising allele carriers at TCF7L2, SCL30A8, GIPR, and C2CD4B. Abnormalities in early insulin secretion were suggested in glucose-raising allele carriers at MTNR1B, GCK, FADS1, DGKB, and PROX1 (lower insulinogenic index; no association with proinsulin or insulin sensitivity). Two loci previously associated with fasting insulin (GCKR and IGF1) were associated with OGTT-derived insulin sensitivity indices in a consistent direction. CONCLUSIONS Genetic loci identified through their effect on hyperglycemia and/or hyperinsulinemia demonstrate considerable heterogeneity in associations with measures of insulin processing, secretion, and sensitivity. Our findings emphasize the importance of detailed physiological characterization of such loci for improved understanding of pathways associated with alterations in glucose homeostasis and eventually type 2 diabetes. Show less

Glucose levels 2 h after an oral glucose challenge are a clinical measure of glucose tolerance used in the diagnosis of type 2 diabetes. We report a meta-analysis of nine genome-wide association studies (n = 15,234 nondiabetic individuals) and a follow-up of 29 independent loci (n = 6,958-30,620). We identify variants at the GIPR locus associated with 2-h glucose level (rs10423928, beta (s.e.m.) = 0.09 (0.01) mmol/l per A allele, P = 2.0 x 10(-15)). The GIPR A-allele carriers also showed decreased insulin secretion (n = 22,492; insulinogenic index, P = 1.0 x 10(-17); ratio of insulin to glucose area under the curve, P = 1.3 x 10(-16)) and diminished incretin effect (n = 804; P = 4.3 x 10(-4)). We also identified variants at ADCY5 (rs2877716, P = 4.2 x 10(-16)), VPS13C (rs17271305, P = 4.1 x 10(-8)), GCKR (rs1260326, P = 7.1 x 10(-11)) and TCF7L2 (rs7903146, P = 4.2 x 10(-10)) associated with 2-h glucose. Of the three newly implicated loci (GIPR, ADCY5 and VPS13C), only ADCY5 was found to be associated with type 2 diabetes in collaborating studies (n = 35,869 cases, 89,798 controls, OR = 1.12, 95% CI 1.09-1.15, P = 4.8 x 10(-18)). Show less

Levels of circulating glucose are tightly regulated. To identify new loci influencing glycemic traits, we performed meta-analyses of 21 genome-wide association studies informative for fasting glucose, fasting insulin and indices of beta-cell function (HOMA-B) and insulin resistance (HOMA-IR) in up to 46,186 nondiabetic participants. Follow-up of 25 loci in up to 76,558 additional subjects identified 16 loci associated with fasting glucose and HOMA-B and two loci associated with fasting insulin and HOMA-IR. These include nine loci newly associated with fasting glucose (in or near ADCY5, MADD, ADRA2A, CRY2, FADS1, GLIS3, SLC2A2, PROX1 and C2CD4B) and one influencing fasting insulin and HOMA-IR (near IGF1). We also demonstrated association of ADCY5, PROX1, GCK, GCKR and DGKB-TMEM195 with type 2 diabetes. Within these loci, likely biological candidate genes influence signal transduction, cell proliferation, development, glucose-sensing and circadian regulation. Our results demonstrate that genetic studies of glycemic traits can identify type 2 diabetes risk loci, as well as loci containing gene variants that are associated with a modest elevation in glucose levels but are not associated with overt diabetes. Show less

Large-scale genome-wide association (GWA) studies have thus far identified 16 loci incontrovertibly associated with obesity-related traits in adults. We examined associations of variants in these loci with anthropometric traits in children and adolescents. Seventeen variants representing 16 obesity susceptibility loci were genotyped in 1,252 children (mean ± SD age 9.7 ± 0.4 years) and 790 adolescents (15.5 ± 0.5 years) from the European Youth Heart Study (EYHS). We tested for association of individual variants and a genetic predisposition score (GPS-17), calculated by summing the number of effect alleles, with anthropometric traits. For 13 variants, summary statistics for associations with BMI were meta-analyzed with previously reported data (N(total) = 13,071 children and adolescents). In EYHS, 15 variants showed associations or trends with anthropometric traits that were directionally consistent with earlier reports in adults. The meta-analysis showed directionally consistent associations with BMI for all 13 variants, of which 9 were significant (0.033-0.098 SD/allele; P < 0.05). The near-TMEM18 variant had the strongest effect (0.098 SD/allele P = 8.5 × 10(-11)). Effect sizes for BMI tended to be more pronounced in children and adolescents than reported earlier in adults for variants in or near SEC16B, TMEM18, and KCTD15, (0.028-0.035 SD/allele higher) and less pronounced for rs925946 in BDNF (0.028 SD/allele lower). Each additional effect allele in the GPS-17 was associated with an increase of 0.034 SD in BMI (P = 3.6 × 10(-5)), 0.039 SD, in sum of skinfolds (P = 1.7 × 10(-7)), and 0.022 SD in waist circumference (P = 1.7 × 10(-4)), which is comparable with reported results in adults (0.039 SD/allele for BMI and 0.033 SD/allele for waist circumference). Most obesity susceptibility loci identified by GWA studies in adults are already associated with anthropometric traits in children/adolescents. Whereas the association of some variants may differ with age, the cumulative effect size is similar. Show less

The neuronal ceroid lipofuscinoses (NCLs) are severe inherited neurodegenerative disorders affecting children. In this disease, lysosomes accumulate autofluorescent storage material and there is death of neurons. Five types of NCL are caused by mutations in lysosomal proteins (CTSD, CLN1/PPT1, CLN2/TTPI, CLN3 and CLN5), and one type is caused by mutations in a protein that recycles between the ER and ERGIC (CLN8). The CLN6 gene underlying a variant of late infantile NCL (vLINCL) was recently identified. It encodes a novel 311 amino acid transmembrane protein. Antisera raised against CLN6 peptides detected a protein of 30 kDa by Western blotting of human cells, which was missing in cells from some CLN6 deficient patients. Using immunofluorescence microscopy, CLN6 was shown to reside in the endoplasmic reticulum (ER). CLN6 protein tagged with GFP at the C-terminus and expressed in HEK293 cells was also found within the ER. Investigation of the effect of five CLN6 disease mutations that affect single amino acids showed that the mutant proteins were retained in the ER. These data suggest that CLN6 is an ER resident protein, the activity of which, despite this location, must contribute to lysosomal function. Show less

The neuronal ceroid lipofuscinoses (NCLs) are a group of autosomal recessive neurodegenerative diseases of childhood. CLN6, the gene mutated in variant late infantile NCL (vLINCL), was recently cloned. We report the identification of eight further mutations in CLN6 making a total of 18 reported mutations. These mutations include missense, nonsense, small deletions or insertions, and two splice-site mutations. Ten mutations affect single amino acids, all of which are conserved across vertebrate species. Minor differences in the pattern of disease symptom evolution can be identified. One patient with a more protracted disease progression was a compound heterozygote for a missense mutation and an unidentified mutation. Fifteen CLN6 mutations occur in one or two families only, and families from the same country do not all share the same mutation. Unlike NCLs caused by mutations in CLN1, CLN3, CLN5, and CLN8, there is no major founder mutation in CLN6. However, one mutation (E72X) is significantly more common in patients from Costa Rica than two other mutations present in that same population. In addition, a 1-bp insertion (c.316insC) is associated with families from Pakistan and I154del may be common in Portugal. A group of Roma Gypsy families from the Czech Republic share two disease-associated haplotypes, one of which is also present in a Pakistani family, consistent with the proposed migration of the Roma from the Indian subcontinent 1,000 years ago. All mutations are recorded in the NCL Mutation Database together with their country of origin for use in the development of rapid screening assays to confirm diagnosis and to facilitate carrier testing appropriate to a population. Show less

One variant form of late infantile neuronal ceroid lipofuscinosis (LINCL) is found predominantly within the Turkish population (CLN7). Exclusion mapping showed that CLN7 was not an allelic variant of known NCL loci (CLN1, CLN2, CLN3, CLN5 or CLN6). Using the method of homozygosity mapping, a genome-wide search was undertaken and a total of 358 microsatellite markers were typed at an average distance of about 10 cM. A region of shared homozygosity was identified on chromosome 8p23. This telomeric region contained the recently identified CLN8 gene. A missense mutation in CLN8 causes progressive epilepsy with mental retardation (EPMR) or Northern epilepsy, which has so far been reported only from Finland and is now classified as an NCL. The mouse model mnd has been shown to carry a 1 bp insertion in the orthologous Cln8 gene. Statistically significant evidence for linkage was obtained in this region, with LOD scores > 3, assuming either homogeneity or heterogeneity. Flanking recombinants defined a critical region of 14 cM between D8S504 and D8S1458 which encompasses CLN8. This suggests that Turkish variant LINCL, despite having an earlier onset and more severe phenotype, may be an allelic variant of Northern epilepsy. However mutation analysis has not so far identified a disease causing mutation within the coding or non-coding exons of CLN8 in the families. The Turkish variant LINCL disease-causing mutation remains to be delineated. Show less

The neuronal ceroid lipofuscinoses (NCLs) represent a group of neurodegenerative disorders characterised by progressive visual failure, neurodegeneration, epilepsy and the accumulation of an autofluorescent lipopigment in neurons and other cells. The main childhood subtypes are infantile (INCL;CLN1), classical late infantile (LINCL;CLN2) and juvenile NCL (JNCL;CLN3), distinguished on the basis of age of onset, clinical course and ultrastructural morphology, and recently genetic analysis. In addition several variant forms of the disease complex have been described as well as a rare adult onset form. Advances in both genetics and biochemistry have led to the identification of the genes for the three main subtypes of childhood NCL and their corresponding protein products and to mapping of two additional genes for two variant forms. The disease causing genes in both INCL and classical LINCL have been shown to encode lysosomal enzymes whilst the JNCL gene codes for a protein whose function is as yet unknown. Show less

Atrophin-1 contains a polyglutamine repeat, expansion of which is responsible for dentatorubral and pallidoluysian atrophy (DRPLA). The normal function of atrophin-1 is unknown. We have identified five atrophin-1 interacting proteins (AIPs) which bind to atrophin-1 in the vicinity of the polyglutamine tract using the yeast two-hybrid system. Four of the interactions were confirmed using in vitro binding assays. All five interactors contained multiple WW domains. Two are novel. The AIPs can be divided into two distinct classes. AIP1 and AIP3/WWP3 are MAGUK-like multidomain proteins containing a number of protein-protein interaction modules, namely a guanylate kinase-like region, two WW domains, and multiple PDZ domains. AIP2/WWP2, AIP4, and AIP5/WWP1 are highly homologous, each having four WW domains and a HECT domain characteristic of ubiquitin ligases. These interactors are similar to recently isolated huntingtin-interacting proteins, suggesting possible commonality of function between two proteins responsible for very similar diseases. Show less

The childhood neuronal ceroid lipofuscinoses (NCLs) are a group of autosomal recessive neurodegenerative disorders characterised by progressive visual failure, neurodegeneration, epilepsy and the accumulation of an autofluorescent lipopigment in neurones and other cells. Three main subtypes have been identified according to age of onset, clinical features and ultrastructural morphology. These are infantile NCL (INCL; CLN1), classical late infantile NCL (LINCL; CLN2) and juvenile NCL (JNCL; CLN3). Several atypical forms of late infantile NCL (LINCL) have also been described including a Finnish variant LINCL (CLN5). The CLN2 gene has been excluded from the CLN1, CLN3 and CLN5 loci. A genome search was initiated using a homozygosity mapping strategy in five classical LINCL and two variant LINCL consanguineous families. A common region of homozygosity was identified on chromosome 11p15 in two of the classical families. Analysis of a further 33 classical LINCL families supported linkage in this region (Zmax = 3.07 at theta = 0.06 at D11S1338). A common region of homozygosity was also observed on chromosome 15q21-23 in the two variant LINCL families. Extension of the analysis to include a further seven families of identical ultrastructural phenotype established linkage to this region (Zmax = 6.00 at theta = 0.00 at D15S1020). Show less