RNA sequencing unravels novel L cell constituents and mechanisms of GLP-1 secretion in human gastric bypass-operated intestine.

AIMS/HYPOTHESIS: Roux-en-Y gastric bypass surgery (RYGB) frequently results in remission of type 2 diabetes as well as exaggerated secretion of glucagon-like peptide-1 (GLP-1). Here, we assessed RYGB-induced transcriptomic alterations in the small intestine and investigated how they were related to the regulation of GLP-1 production and secretion in vitro and in vivo. METHODS: Human jejunal samples taken perisurgically and 1 year post RYGB (n=13) were analysed by RNA-seq. Guided by bioinformatics analysis we targeted four genes involved in cholesterol biosynthesis, which we confirmed to be expressed in human L cells, for potential involvement in GLP-1 regulation using siRNAs in GLUTag and STC-1 cells. Gene expression analyses, GLP-1 secretion measurements, intracellular calcium imaging and RNA-seq were performed in vitro. OGTTs were performed in C57BL/6j and iScd1-/- mice and immunohistochemistry and gene expression analyses were performed ex vivo. RESULTS: Gene Ontology (GO) analysis identified cholesterol biosynthesis as being most affected by RYGB. Silencing or chemical inhibition of stearoyl-CoA desaturase 1 (SCD1), a key enzyme in the synthesis of monounsaturated fatty acids, was found to reduce Gcg expression and secretion of GLP-1 by GLUTag and STC-1 cells. Scd1 knockdown also reduced intracellular Ca2+ signalling and membrane depolarisation. Furthermore, Scd1 mRNA expression was found to be regulated by NEFAs but not glucose. RNA-seq of SCD1 inhibitor-treated GLUTag cells identified altered expression of genes implicated in ATP generation and glycolysis. Finally, gene expression and immunohistochemical analysis of the jejunum of the intestine-specific Scd1 knockout mouse model, iScd1-/-, revealed a twofold higher L cell density and a twofold increase in Gcg mRNA expression. CONCLUSIONS/INTERPRETATION: RYGB caused robust alterations in the jejunal transcriptome, with genes involved in cholesterol biosynthesis being most affected. Our data highlight SCD as an RYGB-regulated L cell constituent that regulates the production and secretion of GLP-1.

Glucose Controls Glucagon Secretion by Regulating Fatty Acid Oxidation in Pancreatic α-Cells.

Whole-body glucose homeostasis is coordinated through secretion of glucagon and insulin from pancreatic islets. When glucose is low, glucagon is released from α-cells to stimulate hepatic glucose production. However, the mechanisms that regulate glucagon secretion from pancreatic α-cells remain unclear. Here we show that in α-cells, the interaction between fatty acid oxidation and glucose metabolism controls glucagon secretion. The glucose-dependent inhibition of glucagon secretion relies on pyruvate dehydrogenase and carnitine palmitoyl transferase 1a activity and lowering of mitochondrial fatty acid oxidation by increases in glucose. This results in reduced intracellular ATP and leads to membrane repolarization and inhibition of glucagon secretion. These findings provide a new framework for the metabolic regulation of the α-cell, where regulation of fatty acid oxidation by glucose accounts for the stimulation and inhibition of glucagon secretion. ARTICLE HIGHLIGHTS: It has become clear that dysregulation of glucagon secretion and α-cell function plays an important role in the development of diabetes, but we do not know how glucagon secretion is regulated. Here we asked whether glucose inhibits fatty acid oxidation in α-cells to regulate glucagon secretion. We found that fatty acid oxidation is required for the inhibitory effects of glucose on glucagon secretion through reductions in ATP. These findings provide a new framework for the regulation of glucagon secretion by glucose.

Formation of Artificial Fermi Surfaces with a Triangular Superlattice on a Conventional Two-Dimensional Electron Gas.

Imposing an external periodic electrostatic potential to the electrons confined in a quantum well makes it possible to engineer synthetic two-dimensional band structures, with electronic properties different from those in the host semiconductor. Here we report the fabrication and study of a tunable triangular artificial lattice on a GaAs/AlGaAs heterostructure where it is possible to transform from the original GaAs band structure and a circular Fermi surface to a new band structure with multiple artificial Fermi surfaces simply by altering a gate bias. For weak electrostatic modulation magnetotransport measurements reveal multiple quantum oscillations and commensurability oscillations due to the electron scattering from the artificial lattice. Increasing the strength of the modulation reveals new commensurability oscillations of the electrons from the artificial Fermi surface scattering from the triangular artificial lattice. These results show that low disorder gate-tunable lateral superlattices can be used to form artificial two-dimensional crystals with designer electronic properties.

Silicon-Aluminum Phase-Transformation-Induced Superconducting Rings.

The development of devices that exhibit both superconducting and semiconducting properties is an important endeavor for emerging quantum technologies. We investigate superconducting nanowires fabricated on a silicon-on-insulator (SOI) platform. Aluminum from deposited contact electrodes is found to interdiffuse with Si along the entire length of the nanowire, over micrometer length scales and at temperatures well below the Al-Si eutectic. The phase-transformed material is conformal with the predefined device patterns. The superconducting properties of a transformed mesoscopic ring formed on a SOI platform are investigated. Low-temperature magnetoresistance oscillations, quantized in units of the fluxoid, h/2e, are observed.

Split-thickness Skin Graft Harvest under Local Anesthetic: A Single Pass Technique.

Adequate local anesthetic, in harvesting a split-thickness skin graft (SSG), traditionally involves multiple passes of a needle across the length and width of the marked donor site. We describe a technique using hyaluronidase to uniformly anaesthetize an SSG donor site with one injection, in one pass, of one needle. 1. Preop application of EMLA cream/AMITOP to the donor site 2. Mix 10 mL 1% lidocaine solution with Adrenaline 1:200,000 with 1 vial of Hyaluronidase 1500 units. The mixture is buffered with 1 mL 8.4% sodium bicarbonate to neutralize acidity and minimize pain. 3. Mark out the SSG donor site 4. Using a 27-G long needle (sterican), enter perpendicular to the skin in the middle of the proximal aspect of the donor site. Inject some local anesthetic subdermally, creating a mound. 5. Change the angle of the needle to 180° and continue to inject the remaining anesthetic along one half of the width of the donor site. 6. Using a rolled 4 × 4 swab, apply firm advancing pressure to distribute the mound across the remaining width and length of marked donor site. 7. As the mound advances, the hyluronidase/anesthetic mixture will distribute uniformly across the donor site within the same plane. The skin blanches secondary to the adrenaline during its distribution. The technique described is a fast, reproducible way to improve patient comfort through the elimination of repeated passes of a needle, distributing the anesthetic uniformly across the donor site, and facilitating the acquisition of an SSG of uniform thickness.

Dysregulation of Glucagon Secretion by Hyperglycemia-Induced Sodium-Dependent Reduction of ATP Production.

Diabetes is a bihormonal disorder resulting from combined insulin and glucagon secretion defects. Mice lacking fumarase (Fh1) in their ß cells (Fh1ßKO mice) develop progressive hyperglycemia and dysregulated glucagon secretion similar to that seen in diabetic patients (too much at high glucose and too little at low glucose). The glucagon secretion defects are corrected by low concentrations of tolbutamide and prevented by the sodium-glucose transport (SGLT) inhibitor phlorizin. These data link hyperglycemia, intracellular Na+ accumulation, and acidification to impaired mitochondrial metabolism, reduced ATP production, and dysregulated glucagon secretion. Protein succination, reflecting reduced activity of fumarase, is observed in α cells from hyperglycemic Fh1ßKO and ß-V59M gain-of-function KATP channel mice, diabetic Goto-Kakizaki rats, and patients with type 2 diabetes. Succination is also observed in renal tubular cells and cardiomyocytes from hyperglycemic Fh1ßKO mice, suggesting that the model can be extended to other SGLT-expressing cells and may explain part of the spectrum of diabetic complications.

Psychosocial Health and Lifestyle Behaviors in Young Adults Receiving Renal Replacement Therapy Compared to the General Population: Findings From the SPEAK Study.

RATIONALE & OBJECTIVE: Patients in late adolescence and early adulthood receiving renal replacement therapy (RRT) face disruption to normal activities, which affects well-being. We aimed to define psychosocial and lifestyle outcomes for young adults on RRT compared to the general population. STUDY DESIGN: We undertook a cross-sectional survey (the SPEAK [Surveying Patients Experiencing Young Adult Kidney Failure] Study) using validated measures and general population comparator data from the Health Survey for England and Avon Longitudinal Study of Parents and Children. Additional clinical information was obtained from the UK Renal Registry. SETTING & PARTICIPANTS: 16- to 30-year-olds receiving RRT. OUTCOMES: Psychosocial health and lifestyle behaviors. ANALYTICAL APPROACH: We compared outcomes between populations using age- and sex-adjusted regression models, weighted to account for response bias by sex, ethnicity, and socioeconomic status. Our findings were used to update recent meta-analyses. RESULTS: We recruited 976 young adults and 64% responded to the survey: 417 (71%) with kidney transplants and 173 (29%) on dialysis therapy. Compared to the general population, young adults on RRT were less likely to be in a relationship and have children and more likely to live in the family home, receive no income, and be unable to work due to health. They had poorer quality of life, worse well-being, and twice the likelihood of a psychological disturbance (OR, 2.7; 95% CI, 2.0-3.7; P<0.001). They reported less smoking, alcohol and drug abuse, and crime. In a meta-analysis, our study showed the greatest differences in quality of life compared to the general population. LIMITATIONS: Cross-sectional study design, meaning that we could not track the impact of treatment changes on the outcomes. CONCLUSIONS: This study involving a large cohort of young adult transplant recipients and dialysis patients provides evidence of worse psychosocial outcomes but more positive lifestyle behaviors in young adults on RRT compared to the age-matched general population.

Adrenaline Stimulates Glucagon Secretion by Tpc2-Dependent Ca2+ Mobilization From Acidic Stores in Pancreatic α-Cells.

Adrenaline is a powerful stimulus of glucagon secretion. It acts by activation of ß-adrenergic receptors, but the downstream mechanisms have only been partially elucidated. Here, we have examined the effects of adrenaline in mouse and human α-cells by a combination of electrophysiology, imaging of Ca2+ and PKA activity, and hormone release measurements. We found that stimulation of glucagon secretion correlated with a PKA- and EPAC2-dependent (inhibited by PKI and ESI-05, respectively) elevation of [Ca2+]i in α-cells, which occurred without stimulation of electrical activity and persisted in the absence of extracellular Ca2+ but was sensitive to ryanodine, bafilomycin, and thapsigargin. Adrenaline also increased [Ca2+]i in α-cells in human islets. Genetic or pharmacological inhibition of the Tpc2 channel (that mediates Ca2+ release from acidic intracellular stores) abolished the stimulatory effect of adrenaline on glucagon secretion and reduced the elevation of [Ca2+]i Furthermore, in Tpc2-deficient islets, ryanodine exerted no additive inhibitory effect. These data suggest that ß-adrenergic stimulation of glucagon secretion is controlled by a hierarchy of [Ca2+]i signaling in the α-cell that is initiated by cAMP-induced Tpc2-dependent Ca2+ release from the acidic stores and further amplified by Ca2+-induced Ca2+ release from the sarco/endoplasmic reticulum.

Sociodemographic, Psychologic Health, and Lifestyle Outcomes in Young Adults on Renal Replacement Therapy.

BACKGROUND AND OBJECTIVES: Young adults receiving RRT face additional challenges in life. The effect of established kidney failure on young adulthood is uncertain. We aimed to establish the psychosocial and lifestyle status of young adults receiving RRT. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Our study was a systematic review and meta-analysis of 16-30-year olds receiving RRT compared with the general population. We selected randomized, controlled trials; cohort studies; or cross-sectional studies without language restriction and extracted proportions of sociodemographic and lifestyle outcomes or validated psychologic health tests producing quality of life, wellbeing, and self-esteem scores. We undertook random effects meta-analysis. RESULTS: There were 60 studies with a total of 15,575 participants. Studies were largely single-center cross-sectional studies of those transplanted in childhood. Compared with healthy peers, young adults on RRT had lower quality of life, which was worse for patients on dialysis (seven studies: standardized mean difference, -1.01; 95% confidence interval [95% CI], -1.32 to -0.70) compared with patients with transplants (nine studies: standardized mean difference, -0.42; 95% CI, -0.64 to -0.20). They were more likely to be unemployed (seven studies: relative risk, 1.89; 95% CI, 1.47 to 2.44) and live in the family home (two studies: relative risk, 1.84; 95% CI, 1.40 to 2.43). They were less likely to be married or have a partner (four studies: relative risk, 0.71; 95% CI, 0.53 to 0.95). Higher education (three studies: relative risk, 1.05; 95% CI, 0.73 to 1.51), alcohol abstinence (three studies: relative risk, 1.96; 95% CI, 0.84 to 4.67), and smoking status (two studies: relative risk, 0.72; 95% CI, 0.36 to 1.44) did not differ. Results were limited by high heterogeneity and a small evidence base, biased toward surviving patients. CONCLUSIONS: Established kidney failure is associated with lower quality of life in young people and limited employment, independence, and relationships compared with healthy peers. PODCAST: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2017_10_19_CJASNPodcast_17_12_.mp3.

Fumarate Hydratase Deletion in Pancreatic ß Cells Leads to Progressive Diabetes.

We explored the role of the Krebs cycle enzyme fumarate hydratase (FH) in glucose-stimulated insulin secretion (GSIS). Mice lacking Fh1 in pancreatic ß cells (Fh1ßKO mice) appear normal for 6-8 weeks but then develop progressive glucose intolerance and diabetes. Glucose tolerance is rescued by expression of mitochondrial or cytosolic FH but not by deletion of Hif1α or Nrf2. Progressive hyperglycemia in Fh1ßKO mice led to dysregulated metabolism in ß cells, a decrease in glucose-induced ATP production, electrical activity, cytoplasmic [Ca2+]i elevation, and GSIS. Fh1 loss resulted in elevated intracellular fumarate, promoting succination of critical cysteines in GAPDH, GMPR, and PARK 7/DJ-1 and cytoplasmic acidification. Intracellular fumarate levels were increased in islets exposed to high glucose and in islets from human donors with type 2 diabetes (T2D). The impaired GSIS in islets from diabetic Fh1ßKO mice was ameliorated after culture under normoglycemic conditions. These studies highlight the role of FH and dysregulated mitochondrial metabolism in T2D.

Increased vimentin in human α- and ß-cells in type 2 diabetes.

Type 2 diabetes (T2DM) is associated with pancreatic islet dysfunction. Loss of ß-cell identity has been implicated via dedifferentiation or conversion to other pancreatic endocrine cell types. How these transitions contribute to the onset and progression of T2DM in vivo is unknown. The aims of this study were to determine the degree of epithelial-to-mesenchymal transition occurring in α and ß cells in vivo and to relate this to diabetes-associated (patho)physiological conditions. The proportion of islet cells expressing the mesenchymal marker vimentin was determined by immunohistochemistry and quantitative morphometry in specimens of pancreas from human donors with T2DM (n = 28) and without diabetes (ND, n = 38) and in non-human primates at different stages of the diabetic syndrome: normoglycaemic (ND, n = 4), obese, hyperinsulinaemic (HI, n = 4) and hyperglycaemic (DM, n = 8). Vimentin co-localised more frequently with glucagon (α-cells) than with insulin (ß-cells) in the human ND group (1.43% total α-cells, 0.98% total ß-cells, median; P < 0.05); these proportions were higher in T2DM than ND (median 4.53% α-, 2.53% ß-cells; P < 0.05). Vimentin-positive ß-cells were not apoptotic, had reduced expression of Nkx6.1 and Pdx1, and were not associated with islet amyloidosis or with bihormonal expression (insulin + glucagon). In non-human primates, vimentin-positive ß-cell proportion was larger in the diabetic than the ND group (6.85 vs 0.50%, medians respectively, P < 0.05), but was similar in ND and HI groups. In conclusion, islet cell expression of vimentin indicates a degree of plasticity and dedifferentiation with potential loss of cellular identity in diabetes. This could contribute to α- and ß-cell dysfunction in T2DM.

Tomographic indices as possible risk factors for progression in pediatric keratoconus.

PURPOSE: To determine whether corneal tomography can help predict the risk of progression of keratoconus in children. METHODS: The medical records of pediatric patients with keratoconus presenting to a large tertiary institution in the UK from 2009 to 2014 were reviewed retrospectively. Patients underwent serial clinical examination and corneal tomography. The minimum follow-up period was 5 months. Patients with a history of eye surgery including corneal crosslinking were excluded. The following tomographic parameters were analyzed: thinnest corneal thickness (TCT), average central corneal keratometry (Km), and maximum central posterior elevation (MCPE). The rate of progressive corneal thinning, in µm/month, was calculated as the difference between TCT on presentation and at the most recent visit divided by the time in months. RESULTS: A total of 36 eyes of 19 patients (10-16 years of age) were included. Mean follow-up was 19 months (range, 5-30 months). Six eyes (17%) developed corneal scarring and 1 eye (3%) developed acute hydrops. Of the 29 eyes that did not develop corneal scarring or hydrops, 24 (83%) demonstrated progressive corneal thinning over the period of the study. Eyes with TCT of <450 µm, Km above 50 D, and MCPE above 50 µm at presentation demonstrated the highest rates of progressive corneal thinning over the study period. CONCLUSIONS: In pediatric keratoconus, lower TCT, higher Km, and higher MCPE on corneal tomography seem to be risk factors for faster rates of progressive corneal thinning.

UK Renal Registry 18th Annual Report: Chapter 4 Demography of Patients Receiving Renal Replacement Therapy in Paediatric Centres in the UK in 2014.

A total of 917 children and young people under 18 years with established renal failure (ERF) were receiving treatment at paediatric nephrology centres in 2014.At the census date (31st December 2014), 79.3% of prevalent paediatric patients aged ,18 years had a functioning kidney transplant, 11.2% were receiving haemodialysis (HD) and 9.5% were receiving peritoneal dialysis (PD). In patients aged ,16 years, prevalence of ERF was 60.4 per million age related population (pmarp) and the incidence 9.4 pmarp. The most common primary renal diagnosis was renal dysplasia+reflux, present in 32.6% of prevalent paediatric patients aged ,16 years. About a third of patients had one or more reported comorbidity at onset of renal replacement therapy (RRT). The improvement in rates of pre-emptive transplantation for those referred early has been maintained over the last 10 years at 37.5%, compared to 27.4% in 2000­2004. At transfer to adult services, 90.3% of patients had a functioning kidney transplant. Survival during childhood amongst children commencing RRT was the lowest in those aged less than two years compared to those aged 12 to less than 16 years with a hazard ratio of 4.1 (confidence interval 2.2­8.0), and in those receiving dialysis compared to having a functioning transplant with a hazard ratio of 6.3 (confidence interval 3.9­10.2).

Spin-orbit interaction in a two-dimensional hole gas at the surface of hydrogenated diamond.

Hydrogenated diamond possesses a unique surface conductivity as a result of transfer doping by surface acceptors. Yet, despite being extensively studied for the past two decades, little is known about the system at low temperature, particularly whether a two-dimensional hole gas forms at the diamond surface. Here we report that (100) diamond, when functionalized with hydrogen, supports a p-type spin-3/2 two-dimensional surface conductivity with a spin-orbit interaction of 9.74 ± 0.1 meV through the observation of weak antilocalization effects in magneto-conductivity measurements at low temperature. Fits to 2D localization theory yield a spin relaxation length of 30 ± 1 nm and a spin-relaxation time of ∼ 0.67 ± 0.02 ps. The existence of a 2D system with spin orbit coupling at the surface of a wide band gap insulating material has great potential for future applications in ferromagnet-semiconductor and superconductor-semiconductor devices.

HNF1B-associated renal and extra-renal disease-an expanding clinical spectrum.

Heterozygous mutations in the gene that encodes the transcription factor hepatocyte nuclear factor 1ß (HNF1B) represent the most common known monogenic cause of developmental kidney disease. Renal cysts are the most frequently detected feature of HNF1B-associated kidney disease; however, other structural abnormalities, including single kidneys and renal hypoplasia, and electrolyte abnormalities can also occur. Extra-renal phenotypes might also be observed; consequently, HNF1B-associated disease is considered a multi-system disorder. Other clinical features include early-onset diabetes mellitus, pancreatic hypoplasia, genital tract malformations, abnormal liver function and early-onset gout. Heterozygous mutations in the coding region or splice sites of HNF1B, and complete gene deletion, each account for ∼50% of all cases of HNF1B-associated disease, respectively, and often arise spontaneously. There is no clear genotype-phenotype correlation, consistent with haploinsufficiency as the disease mechanism. Data from animal models suggest that HNF1B has an important function during several stages of nephrogenesis; however, the precise signalling pathways remain to be elucidated. This Review discusses the genetics and molecular pathways that lead to disease development, summarizes the reported renal and extra-renal phenotypes, and identifies areas for future research in HNF1B-associated disease.

Impact of month of birth on the development of autoimmune thyroid disease in the United Kingdom and Europe.

CONTEXT: Viral/bacterial infection is proposed as a trigger for the autoimmune thyroid diseases (AITD): Graves' disease (GD) and Hashimoto's thyroiditis (HT). Previous studies in European Caucasian AITD subjects found higher birth rates in the autumn/winter, suggesting those born in the autumn/winter experience increased viral/bacterial exposure after birth, impacting upon immune system development and predisposing to AITD later in life. OBJECTIVE: Month of birth effects were investigated in three independent European Caucasian AITD datasets. DESIGN: Variation in GD and HT onset was compared across months and seasons, with fluctuations across all 12 months analyzed using a Walter-Elwood test. SETTING: The study was conducted at a research laboratory. PATIENTS: National UK Caucasian AITD Case Control Collection (2746 GD and 502 HT compared with 1 423 716 UK births), National UK Caucasian GD Family Collection (239 GD and 227 unaffected siblings), and OXAGEN AITD Caucasian Family Collection (885 GD, 717 HT, and 794 unaffected siblings of European Caucasian decent). MAIN OUTCOME MEASURES: Case-control and family-based association studies were measured. RESULTS: No consistent month of birth effects were detected in GD females or males across all three collections. In HT females from the OXAGEN AITD Caucasian Family Collection, slightly higher birth rates were detected in autumn (Walter's test statistic = 7.47, P = .024) however, this was not seen in the HT females from the case-control cohort. CONCLUSION: Our results suggest in UK/Northern European Caucasian GD subjects, month of birth does not impact on AITD development. Although some month of birth effects for HT females in one collection cannot be excluded, only further work in larger European Caucasian AITD collections can confirm these effects.

Identification of novel genetic Loci associated with thyroid peroxidase antibodies and clinical thyroid disease.

Autoimmune thyroid diseases (AITD) are common, affecting 2-5% of the general population. Individuals with positive thyroid peroxidase antibodies (TPOAbs) have an increased risk of autoimmune hypothyroidism (Hashimoto's thyroiditis), as well as autoimmune hyperthyroidism (Graves' disease). As the possible causative genes of TPOAbs and AITD remain largely unknown, we performed GWAS meta-analyses in 18,297 individuals for TPOAb-positivity (1769 TPOAb-positives and 16,528 TPOAb-negatives) and in 12,353 individuals for TPOAb serum levels, with replication in 8,990 individuals. Significant associations (P<5×10(-8)) were detected at TPO-rs11675434, ATXN2-rs653178, and BACH2-rs10944479 for TPOAb-positivity, and at TPO-rs11675434, MAGI3-rs1230666, and KALRN-rs2010099 for TPOAb levels. Individual and combined effects (genetic risk scores) of these variants on (subclinical) hypo- and hyperthyroidism, goiter and thyroid cancer were studied. Individuals with a high genetic risk score had, besides an increased risk of TPOAb-positivity (OR: 2.18, 95% CI 1.68-2.81, P = 8.1×10(-8)), a higher risk of increased thyroid-stimulating hormone levels (OR: 1.51, 95% CI 1.26-1.82, P = 2.9×10(-6)), as well as a decreased risk of goiter (OR: 0.77, 95% CI 0.66-0.89, P = 6.5×10(-4)). The MAGI3 and BACH2 variants were associated with an increased risk of hyperthyroidism, which was replicated in an independent cohort of patients with Graves' disease (OR: 1.37, 95% CI 1.22-1.54, P = 1.2×10(-7) and OR: 1.25, 95% CI 1.12-1.39, P = 6.2×10(-5)). The MAGI3 variant was also associated with an increased risk of hypothyroidism (OR: 1.57, 95% CI 1.18-2.10, P = 1.9×10(-3)). This first GWAS meta-analysis for TPOAbs identified five newly associated loci, three of which were also associated with clinical thyroid disease. With these markers we identified a large subgroup in the general population with a substantially increased risk of TPOAbs. The results provide insight into why individuals with thyroid autoimmunity do or do not eventually develop thyroid disease, and these markers may therefore predict which TPOAb-positives are particularly at risk of developing clinical thyroid dysfunction.

The HNF4A R76W mutation causes atypical dominant Fanconi syndrome in addition to a ß cell phenotype.

BACKGROUND: Mutation specific effects in monogenic disorders are rare. We describe atypical Fanconi syndrome caused by a specific heterozygous mutation in HNF4A. Heterozygous HNF4A mutations cause a beta cell phenotype of neonatal hyperinsulinism with macrosomia and young onset diabetes. Autosomal dominant idiopathic Fanconi syndrome (a renal proximal tubulopathy) is described but no genetic cause has been defined. METHODS AND RESULTS: We report six patients heterozygous for the p.R76W HNF4A mutation who have Fanconi syndrome and nephrocalcinosis in addition to neonatal hyperinsulinism and macrosomia. All six displayed a novel phenotype of proximal tubulopathy, characterised by generalised aminoaciduria, low molecular weight proteinuria, glycosuria, hyperphosphaturia and hypouricaemia, and additional features not seen in Fanconi syndrome: nephrocalcinosis, renal impairment, hypercalciuria with relative hypocalcaemia, and hypermagnesaemia. This was mutation specific, with the renal phenotype not being seen in patients with other HNF4A mutations. In silico modelling shows the R76 residue is directly involved in DNA binding and the R76W mutation reduces DNA binding affinity. The target(s) selectively affected by altered DNA binding of R76W that results in Fanconi syndrome is not known. CONCLUSIONS: The HNF4A R76W mutation is an unusual example of a mutation specific phenotype, with autosomal dominant atypical Fanconi syndrome in addition to the established beta cell phenotype.

An unusual case of intraorbital foreign body and its management.

A 36-year-old aboriginal female presented following an assault with a wooden fence paling. Examination revealed a wooden object protruding lateral to the left eyebrow. CT scan showed a blow-in fracture of lateral orbital wall and a hypodense foreign body causing indentation of the globe and stretching of the optic nerve. The case was managed successfully with complete recovery of the visual acuity on day 1 post-surgery. This case highlights the importance of prompt removal of large lateral wooden intraorbital foreign body to achieve an excellent visual outcome.

Prevalence in the General Population of a CFH Sequence Variant Associated with Atypical Haemolytic Uraemic Syndrome in an Extensive Family from Southwest England.

BACKGROUND/AIMS: Twenty-five members of a family from the county of Devon in England have been affected by atypical haemolytic uraemic syndrome (aHUS) associated with a CFH mutation (c.3643C>G; p.Arg1215Gly). A 65-year-old male was diagnosed with aHUS after losing a renal transplant to a thrombotic microangiopathy. Subsequent mutation screening revealed the same CFH mutation without him being knowingly related to the local kindred. We designed a study to investigate the prevalence of this mutation in the local area. In addition, we examined the diagnoses of pre-existing haemodialysis patients to determine whether other patients might unknowingly be at risk of carrying the same CFH mutation. METHODS: The Exeter Ten Thousand (EXTEND) study aims to recruit 10,000 healthy volunteers over the age of 18 years living within 25 miles of Exeter in Devon. We genotyped DNA from 4,000 EXTEND subjects for CFH c.3643C>G; p.Arg1215Gly. We reviewed the diagnoses of 294 haemodialysis patients in the Devon area and genotyped 7 patients with either end-stage renal disease of unknown aetiology, malignant hypertension or renovascular disease. RESULTS: CFH c.3643C>G; p.Arg1215Gly was not detected in any of the 7 haemodialysis patients or the 4,000 individuals within the EXTEND study. CONCLUSIONS: We conclude that CFH c.3643C>G; p.Arg1215Gly is not endemic in Devon. This reinforces our existing practice of genotyping only patients with kidney disease and evidence of a thrombotic microangiopathy for this mutation. This is the first study looking at the prevalence of CFH mutations in the general population.