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SIGNIFICANCE STATEMENT: Kidney stone disease is a common disorder with poorly understood pathophysiology. Observational and genetic studies indicate that adiposity is associated with an increased risk of kidney stone disease. However, the relative contribution of general and central adipose depots and the mechanisms by which effects of adiposity on kidney stone disease are mediated have not been defined. Using conventional and genetic epidemiological techniques, we demonstrate that general and central adiposity are independently associated with kidney stone disease. In addition, one mechanism by which central adiposity increases risk of kidney stone disease is by increasing serum calcium concentration. Therapies targeting adipose depots may affect calcium homeostasis and help to prevent kidney stone disease. BACKGROUND: Kidney stone disease affects approximately 10% of individuals in their lifetime and is frequently recurrent. The disease is linked to obesity, but the mechanisms mediating this association are uncertain. METHODS: Associations of adiposity and incident kidney stone disease were assessed in the UK Biobank over a mean of 11.6 years/person. Genome-wide association studies and Mendelian randomization (MR) analyses were undertaken in the UK Biobank, FinnGen, and in meta-analyzed cohorts to identify factors that affect kidney stone disease risk. RESULTS: Observational analyses on UK Biobank data demonstrated that increasing central and general adiposity is independently associated with incident kidney stone formation. Multivariable MR, using meta-analyzed UK Biobank and FinnGen data, established that risk of kidney stone disease increases by approximately 21% per one standard deviation increase in body mass index (BMI, a marker of general adiposity) independent of waist-to-hip ratio (WHR, a marker of central adiposity) and approximately 24% per one standard deviation increase of WHR independent of BMI. Genetic analyses indicate that higher WHR, but not higher BMI, increases risk of kidney stone disease by elevating adjusted serum calcium concentrations (ß=0.12 mmol/L); WHR mediates 12%-15% of its effect on kidney stone risk in this way. CONCLUSIONS: Our study indicates that visceral adipose depots elevate serum calcium concentrations, resulting in increased risk of kidney stone disease. These findings highlight the importance of weight loss in individuals with recurrent kidney stones and suggest that therapies targeting adipose depots may affect calcium homeostasis and contribute to prevention of kidney stone disease.
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Adiposidade , Cálculos Renais , Humanos , Adiposidade/genética , Cálcio , Fatores de Risco , Estudo de Associação Genômica Ampla , Obesidade/complicações , Obesidade Abdominal/complicações , Obesidade Abdominal/genética , Relação Cintura-Quadril , Índice de Massa Corporal , Cálculos Renais/epidemiologia , Cálculos Renais/etiologia , Análise da Randomização MendelianaRESUMO
OBJECTIVES: To determine the clinical utility of blood tests as a screening tool for metabolic abnormalities in patients with kidney stone disease. SUBJECTS AND METHODS: Clinical and biochemical data from 709 patients attending the Oxford University Hospitals NHS Foundation Trust for assessment and treatment of kidney stones were prospectively collected between April 2011 and February 2017. Data were analysed to determine the utility of serum calcium, parathyroid hormone (PTH), urate, chloride, bicarbonate, potassium and phosphate assays in screening for primary hyperparathyroidism, normocalcaemic hyperparathyroidism, hyperuricosuria, distal renal tubular acidosis (dRTA) and hypercalciuria. RESULTS: An elevated serum calcium level was detected in 2.3% of patients. Further investigations prompted by this finding resulted in a diagnosis of primary hyperparathyroidism in 0.2% of men and 4.6% of women for whom serum calcium was recorded. An elevated serum PTH level in the absence of hypercalcaemia was detected in 15.1% of patients. Of these patients, 74.6% were vitamin D-insufficient; no patients were diagnosed with normocalcaemic hyperparathyroidism. Hyperuricosuria was present in 21.6% of patients and hypercalciuria in 47.1%. Hyperuricaemia was not associated with hyperuricosuria, nor was hypophosphataemia associated with hypercalciuria. No patient was highlighted as being at risk of dRTA using serum chloride and bicarbonate as screening tests. CONCLUSION: This study indicates that individuals presenting with renal calculi should undergo metabolic screening with a serum calcium measurement alone. Use of additional blood tests to screen for metabolic disorders is not cost-effective and may provide false reassurance that metabolic abnormalities are not present. A full metabolic assessment with 24-h urine collection should be undertaken in recurrent stone formers and in those at high risk of future stone disease to identify potentially treatable metabolic abnormalities.
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Acidose Tubular Renal/diagnóstico , Hipercalciúria/diagnóstico , Hiperparatireoidismo/diagnóstico , Cálculos Renais/sangue , Doenças Metabólicas/sangue , Doenças Metabólicas/diagnóstico , Acidose Tubular Renal/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Bicarbonatos/sangue , Cálcio/sangue , Cálcio/urina , Cloretos/sangue , Feminino , Testes Hematológicos , Humanos , Hipercalciúria/sangue , Hiperparatireoidismo/sangue , Hipofosfatemia/sangue , Hipofosfatemia/diagnóstico , Cálculos Renais/etiologia , Masculino , Doenças Metabólicas/complicações , Pessoa de Meia-Idade , Hormônio Paratireóideo/sangue , Fosfatos/sangue , Potássio/sangue , Ácido Úrico/sangue , Ácido Úrico/urina , Adulto JovemAssuntos
Estudos Transversais , Gravidez , Feminino , Humanos , Inquéritos e Questionários , Reino UnidoRESUMO
Germline loss- and gain-of-function mutations of G-protein α-11 (Gα11), which couples the calcium-sensing receptor (CaSR) to intracellular calcium (Ca(2+) i) signaling, lead to familial hypocalciuric hypercalcemia type 2 (FHH2) and autosomal dominant hypocalcemia type 2 (ADH2), respectively, whereas somatic Gα11 mutations mediate uveal melanoma development by constitutively up-regulating MAPK signaling. Cinacalcet and NPS-2143 are allosteric CaSR activators and inactivators, respectively, that ameliorate signaling disturbances associated with CaSR mutations, but their potential to modulate abnormalities of the downstream Gα11 protein is unknown. This study investigated whether cinacalcet and NPS-2143 may rectify Ca(2+) i alterations associated with FHH2- and ADH2-causing Gα11 mutations, and evaluated the influence of germline gain-of-function Gα11 mutations on MAPK signaling by measuring ERK phosphorylation, and assessed the effect of NPS-2143 on a uveal melanoma Gα11 mutant. WT and mutant Gα11 proteins causing FHH2, ADH2 or uveal melanoma were transfected in CaSR-expressing HEK293 cells, and Ca(2+) i and ERK phosphorylation responses measured by flow-cytometry and Alphascreen immunoassay following exposure to extracellular Ca(2+) (Ca(2+) o) and allosteric modulators. Cinacalcet and NPS-2143 rectified the Ca(2+) i responses of FHH2- and ADH2-associated Gα11 loss- and gain-of-function mutations, respectively. ADH2-causing Gα11 mutations were demonstrated not to be constitutively activating and induced ERK phosphorylation following Ca(2+) o stimulation only. The increased ERK phosphorylation associated with ADH2 and uveal melanoma mutants was rectified by NPS-2143. These findings demonstrate that CaSR-targeted compounds can rectify signaling disturbances caused by germline and somatic Gα11 mutations, which respectively lead to calcium disorders and tumorigenesis; and that ADH2-causing Gα11 mutations induce non-constitutive alterations in MAPK signaling.
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Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/metabolismo , Hipercalcemia/metabolismo , Hipocalcemia/metabolismo , Mutação de Sentido Incorreto , Receptores de Detecção de Cálcio/metabolismo , Transdução de Sinais , Regulação Alostérica/efeitos dos fármacos , Regulação Alostérica/genética , Substituição de Aminoácidos , Cinacalcete/farmacologia , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/genética , Células HEK293 , Humanos , Hipercalcemia/genética , Hipocalcemia/genética , Naftalenos/farmacologia , Receptores de Detecção de Cálcio/genéticaRESUMO
The adaptor protein-2 sigma subunit (AP2σ2) is pivotal for clathrin-mediated endocytosis of plasma membrane constituents such as the calcium-sensing receptor (CaSR). Mutations of the AP2σ2 Arg15 residue result in familial hypocalciuric hypercalcaemia type 3 (FHH3), a disorder of extracellular calcium (Ca(2+) o) homeostasis. To elucidate the role of AP2σ2 in Ca(2+) o regulation, we investigated 65 FHH probands, without other FHH-associated mutations, for AP2σ2 mutations, characterized their functional consequences and investigated the genetic mechanisms leading to FHH3. AP2σ2 mutations were identified in 17 probands, comprising 5 Arg15Cys, 4 Arg15His and 8 Arg15Leu mutations. A genotype-phenotype correlation was observed with the Arg15Leu mutation leading to marked hypercalcaemia. FHH3 probands harboured additional phenotypes such as cognitive dysfunction. All three FHH3-causing AP2σ2 mutations impaired CaSR signal transduction in a dominant-negative manner. Mutational bias was observed at the AP2σ2 Arg15 residue as other predicted missense substitutions (Arg15Gly, Arg15Pro and Arg15Ser), which also caused CaSR loss-of-function, were not detected in FHH probands, and these mutations were found to reduce the numbers of CaSR-expressing cells. FHH3 probands had significantly greater serum calcium (sCa) and magnesium (sMg) concentrations with reduced urinary calcium to creatinine clearance ratios (CCCR) in comparison with FHH1 probands with CaSR mutations, and a calculated index of sCa × sMg/100 × CCCR, which was ≥ 5.0, had a diagnostic sensitivity and specificity of 83 and 86%, respectively, for FHH3. Thus, our studies demonstrate AP2σ2 mutations to result in a more severe FHH phenotype with genotype-phenotype correlations, and a dominant-negative mechanism of action with mutational bias at the Arg15 residue.
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Complexo 2 de Proteínas Adaptadoras/genética , Subunidades sigma do Complexo de Proteínas Adaptadoras/genética , Códon , Genes Dominantes , Estudos de Associação Genética , Hipercalcemia/congênito , Mutação , Complexo 2 de Proteínas Adaptadoras/química , Subunidades sigma do Complexo de Proteínas Adaptadoras/química , Adolescente , Adulto , Substituição de Aminoácidos , Biomarcadores , Linhagem Celular , Criança , Pré-Escolar , Diagnóstico Diferencial , Feminino , Expressão Gênica , Humanos , Hipercalcemia/diagnóstico , Hipercalcemia/genética , Lactente , Masculino , Pessoa de Meia-Idade , Modelos Moleculares , Linhagem , Fenótipo , Conformação Proteica , Relação Estrutura-Atividade , Adulto JovemRESUMO
BACKGROUND: Familial hypocalciuric hypercalcemia is a genetically heterogeneous disorder with three variants: types 1, 2, and 3. Type 1 is due to loss-of-function mutations of the calcium-sensing receptor, a guanine nucleotide-binding protein (G-protein)-coupled receptor that signals through the G-protein subunit α11 (Gα11). Type 3 is associated with adaptor-related protein complex 2, sigma 1 subunit (AP2S1) mutations, which result in altered calcium-sensing receptor endocytosis. We hypothesized that type 2 is due to mutations effecting Gα11 loss of function, since Gα11 is involved in calcium-sensing receptor signaling, and its gene (GNA11) and the type 2 locus are colocalized on chromosome 19p13.3. We also postulated that mutations effecting Gα11 gain of function, like the mutations effecting calcium-sensing receptor gain of function that cause autosomal dominant hypocalcemia type 1, may lead to hypocalcemia. METHODS: We performed GNA11 mutational analysis in a kindred with familial hypocalciuric hypercalcemia type 2 and in nine unrelated patients with familial hypocalciuric hypercalcemia who did not have mutations in the gene encoding the calcium-sensing receptor (CASR) or AP2S1. We also performed this analysis in eight unrelated patients with hypocalcemia who did not have CASR mutations. In addition, we studied the effects of GNA11 mutations on Gα11 protein structure and calcium-sensing receptor signaling in human embryonic kidney 293 (HEK293) cells. RESULTS: The kindred with familial hypocalciuric hypercalcemia type 2 had an in-frame deletion of a conserved Gα11 isoleucine (Ile200del), and one of the nine unrelated patients with familial hypocalciuric hypercalcemia had a missense GNA11 mutation (Leu135Gln). Missense GNA11 mutations (Arg181Gln and Phe341Leu) were detected in two unrelated patients with hypocalcemia; they were therefore identified as having autosomal dominant hypocalcemia type 2. All four GNA11 mutations predicted disrupted protein structures, and assessment on the basis of in vitro expression showed that familial hypocalciuric hypercalcemia type 2-associated mutations decreased the sensitivity of cells expressing calcium-sensing receptors to changes in extracellular calcium concentrations, whereas autosomal dominant hypocalcemia type 2-associated mutations increased cell sensitivity. CONCLUSIONS: Gα11 mutants with loss of function cause familial hypocalciuric hypercalcemia type 2, and Gα11 mutants with gain of function cause a clinical disorder designated as autosomal dominant hypocalcemia type 2. (Funded by the United Kingdom Medical Research Council and others.).
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Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/genética , Subunidades alfa de Proteínas de Ligação ao GTP/genética , Hipercalcemia/genética , Hipocalcemia/genética , Mutação , Cálcio/análise , Análise Mutacional de DNA , Líquido Extracelular/química , Feminino , Subunidades alfa de Proteínas de Ligação ao GTP/química , Genes Dominantes , Mutação em Linhagem Germinativa , Heterozigoto , Humanos , Masculino , Modelos Moleculares , Linhagem , Conformação Proteica , Transdução de SinaisAssuntos
Complexo 2 de Proteínas Adaptadoras/genética , Subunidades sigma do Complexo de Proteínas Adaptadoras/genética , Calcimiméticos/uso terapêutico , Cinacalcete/uso terapêutico , Hipercalcemia/tratamento farmacológico , Adulto , Feminino , Humanos , Hipercalcemia/genética , Masculino , Pessoa de Meia-Idade , MutaçãoRESUMO
Objectives: The aim was to assess the prevalence of never events (NEs) specific to urology in the United Kingdom and identify commonly occurring themes. Methods: Data from the National Health Service (NHS) NEs website were obtained and all NEs from 2012 to 2022 were reviewed. Urology-specific NEs were identified and further analysed in their respective categories. Data regarding the total number of surgical procedures performed in the NHS specific to each specialty were obtained via the NHS Hospital Episode Statistics website. Results: There were 3972 NEs recorded over the 10-year period with 95 (2.4%) of these as a result of urology surgery. The most common surgical intervention associated with a urological NE was ureteric stenting, which comprised 45/95 (47.4%) of all analysed NEs. These consisted of wrong site ureteric stent insertion (n = 29), wrong site ureteric stent removal (n = 9), wrong stent type (n = 5) and retained guidewires (n = 2). There were 7.14 million urology surgeries performed in the 10-year period, and prevalence was 0.0013%. Conclusion: NEs are fully preventable serious incidents in the NHS. This is the first study to investigate the prevalence of NEs in urology in the United Kingdom. This study demonstrates that in the last 10 years the prevalence of urology NEs is low at 0.0013%, with ureteric stent procedures accounting for more than half of the NEs. Urologists should be mindful of the potential for wrong site surgery in urologic stenting procedures.
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Mendelian randomization (MR) is a genetic epidemiological technique that uses genetic variation to infer causal relationships between modifiable exposures and outcome variables. Conventional observational epidemiological studies are subject to bias from a range of sources; MR analyses can offer an advantage in that they are less prone to bias as they use genetic variants inherited at conception as "instrumental variables" which are proxies of an exposure. However, as with all research tools, MR studies must be carefully designed to yield valuable insights into causal relationships between exposures and outcomes, and to avoid biased or misleading results that undermine the validity of the causal inferences drawn from the study. In this review we outline Mendel's laws of inheritance, the assumptions and principles that underlie MR, MR study designs and methods, and how MR analyses can be applied, and reported. Using the example of serum phosphate concentrations on liability to kidney stone disease we illustrate how MR estimates may be visualized and, finally, we contextualize MR in bone and mineral research including exemplifying how this technique could be employed to inform clinical studies and future guidelines concerning bone mineral density and fracture risk. This review provides a framework to enhance understanding of how MR may be used to triangulate evidence and progress research in bone and mineral metabolism as we strive to infer causal effects in health and disease.
Mendelian randomization is a powerful tool used by researchers to understand how factors like lifestyle choices or medical conditions affect our health. Some research studies can be hampered by inaccurate information or measurements which mean the results are unreliable. Mendelian randomization uses genetic information to evade this problem. Because a person's genetic information does not change the studies can provide more reliable conclusions about how different factors influence our health. This review provides an overview of Mendelian randomization principles, its applications, and how researchers in bone and mineral research have used it to uncover cause-and-effect relationships.
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A 74-year-old man was suffering from nine months of perineal pain and progressive worsening of urinary symptoms including nocturia and urgency. His prostate-specific antigen (PSA) levels were 1.48 ng/mL at the time of referral. Initially, a differential diagnosis of prostatitis or seminal vesicle inflammation was made, and four weeks of antibiotics were prescribed, which were later extended to six weeks due to failure of symptoms to resolve. Magnetic resonance imaging (MRI) of the prostate was then conducted. The impression was that there was ejaculatory duct obstruction caused by enlarged seminal vesicles with no evidence of significant prostate cancer. The prostate-specific antigen density (PSAd) was 0.04, and the prostate imaging reporting and data system (PIRADS) score was I-II. A CT chest with contrast was conducted for further investigation of pulmonary nodules found on the CT urogram. It revealed multiple calcified pulmonary nodules which were suspicious of malignancy. A CT-guided biopsy of one of the pulmonary nodules was taken, and histopathological analysis revealed a mucinous adenocarcinoma. A transurethral resection of the prostate (TURP) was then performed. Histopathological analysis of the prostatic surgical specimen revealed invasive mucinous adenocarcinoma. Based on the findings, a diagnosis of mucinous adenocarcinoma of the prostate with atypical lung metastasis without osseous or regional lymph node involvement was made, stage T4 N0 M1a. The patient is currently on a treatment regimen consisting of carboplatin, pemetrexed, and pembrolizumab.
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CONTEXT: Familial hypocalciuric hypercalcemia type 1 (FHH-1) defines an autosomal dominant disease, related to mutations in the CASR gene, with mild hypercalcemia in most cases. Cases of FHH-1 with a short QT interval have not been reported to date. OBJECTIVE: Three family members presented with FHH-1 and short QT interval (<360 ms), a condition that could lead to cardiac arrhythmias, and the effects of cinacalcet, an allosteric modulator of the CaSR, in rectifying the abnormal sensitivity of the mutant CaSR and in correcting the short QT interval were determined. METHODS: CASR mutational analysis was performed by next-generation sequencing and functional consequences of the identified CaSR variant (p.Ile555Thr), and effects of cinacalcet were assessed in HEK293 cells expressing wild-type and variant CaSRs. A cinacalcet test consisting of administration of 30 mg cinacalcet (8 Am) followed by hourly measurement of serum calcium, phosphate, and parathyroid hormone during 8 hours and an electrocardiogram was performed. RESULTS: The CaSR variant (p.Ile555Thr) was confirmed in all 3 FHH-1 patients and was shown to be associated with a loss of function that was ameliorated by cinacalcet. Cinacalcet decreased parathyroid hormone by >50% within two hours, and decreases in serum calcium and increases in serum phosphate occurred within 8 hours, with rectification of the QT interval, which remained normal after 3 months of cinacalcet treatment. CONCLUSION: Our results indicate that FHH-1 patients should be assessed for a short QT interval and a cinacalcet test used to select patients who are likely to benefit from this treatment.
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Hipercalcemia , Hiperparatireoidismo , Humanos , Hipercalcemia/tratamento farmacológico , Hipercalcemia/genética , Cinacalcete/uso terapêutico , Cálcio , Células HEK293 , Mutação , Hormônio Paratireóideo , Fosfatos , Receptores de Detecção de Cálcio/genéticaRESUMO
Familial hypocalciuric hypercalcemia type 2 (FHH2) and autosomal dominant hypocalcemia type 2 (ADH2) are due to loss- and gain-of-function mutations, respectively, of the GNA11 gene that encodes the G protein subunit Gα11, a signaling partner of the calcium-sensing receptor (CaSR). To date, four probands with FHH2-associated Gα11 mutations and eight probands with ADH2-associated Gα11 mutations have been reported. In a 10-year period, we identified 37 different germline GNA11 variants in >1200 probands referred for investigation of genetic causes for hypercalcemia or hypocalcemia, comprising 14 synonymous, 12 noncoding, and 11 nonsynonymous variants. The synonymous and noncoding variants were predicted to be benign or likely benign by in silico analysis, with 5 and 3, respectively, occurring in both hypercalcemic and hypocalcemic individuals. Nine of the nonsynonymous variants (Thr54Met, Arg60His, Arg60Leu, Gly66Ser, Arg149His, Arg181Gln, Phe220Ser, Val340Met, Phe341Leu) identified in 13 probands have been reported to be FHH2- or ADH2-causing. Of the remaining nonsynonymous variants, Ala65Thr was predicted to be benign, and Met87Val, identified in a hypercalcemic individual, was predicted to be of uncertain significance. Three-dimensional homology modeling of the Val87 variant suggested it was likely benign, and expression of Val87 variant and wild-type Met87 Gα11 in CaSR-expressing HEK293 cells revealed no differences in intracellular calcium responses to alterations in extracellular calcium concentrations, consistent with Val87 being a benign polymorphism. Two noncoding region variants, a 40bp-5'UTR deletion and a 15bp-intronic deletion, identified only in hypercalcemic individuals, were associated with decreased luciferase expression in vitro but no alterations in GNA11 mRNA or Gα11 protein levels in cells from the patient and no abnormality in splicing of the GNA11 mRNA, respectively, confirming them to be benign polymorphisms. Thus, this study identified likely disease-causing GNA11 variants in <1% of probands with hypercalcemia or hypocalcemia and highlights the occurrence of GNA11 rare variants that are benign polymorphisms. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Hipercalcemia , Hipocalcemia , Humanos , Hipocalcemia/genética , Hipocalcemia/metabolismo , Hipercalcemia/genética , Cálcio/metabolismo , Células HEK293 , Mutação/genética , Receptores de Detecção de Cálcio/genética , Receptores de Detecção de Cálcio/metabolismo , Subunidades alfa de Proteínas de Ligação ao GTP/genética , Subunidades alfa de Proteínas de Ligação ao GTP/metabolismoRESUMO
To discover rare disease-gene associations, we developed a gene burden analytical framework and applied it to rare, protein-coding variants from whole genome sequencing of 35,008 cases with rare diseases and their family members recruited to the 100,000 Genomes Project (100KGP). Following in silico triaging of the results, 88 novel associations were identified including 38 with existing experimental evidence. We have published the confirmation of one of these associations, hereditary ataxia with UCHL1 , and independent confirmatory evidence has recently been published for four more. We highlight a further seven compelling associations: hypertrophic cardiomyopathy with DYSF and SLC4A3 where both genes show high/specific heart expression and existing associations to skeletal dystrophies or short QT syndrome respectively; monogenic diabetes with UNC13A with a known role in the regulation of ß cells and a mouse model with impaired glucose tolerance; epilepsy with KCNQ1 where a mouse model shows seizures and the existing long QT syndrome association may be linked; early onset Parkinson's disease with RYR1 with existing links to tremor pathophysiology and a mouse model with neurological phenotypes; anterior segment ocular abnormalities associated with POMK showing expression in corneal cells and with a zebrafish model with developmental ocular abnormalities; and cystic kidney disease with COL4A3 showing high renal expression and prior evidence for a digenic or modifying role in renal disease. Confirmation of all 88 associations would lead to potential diagnoses in 456 molecularly undiagnosed cases within the 100KGP, as well as other rare disease patients worldwide, highlighting the clinical impact of a large-scale statistical approach to rare disease gene discovery.
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BACKGROUND: Calcium kidney stones are common and recurrences are often not preventable by available empiric remedies. Their etiology is multifactorial and polygenic, and an increasing number of genes are implicated. Their identification will enable improved management. METHODS: DNA from three stone-formers in a Southampton family (UK) and two from an Italian family were analyzed independently by whole exome sequencing and selected variants were genotyped across all available members of both pedigrees. A disease variant of SLC25A25 (OMIM 608745), encoding the mitochondrial ATP-Mg/Pi carrier 3 (APC3) was identified, and analyzed structurally and functionally with respect to its calcium-regulated transport activity. RESULTS: All five patients had a heterozygous dominant SLC25A25 variant (rs140777921; GRCh37.p13: chr 9 130868670 G>C; p.Gln349His; Reference Sequence NM_001006641.3). Non-stone formers also carried the variant indicating incomplete penetrance. Modeling suggests that the variant lacks a conserved polar interaction, which may cause structural instability. Calcium-regulated ATP transport was reduced to ~20% of the wild type, showing a large reduction in function. CONCLUSION: The transporter is important in regulating mitochondrial ATP production. This rare variant may increase urine lithogenicity through impaired provision of ATP for solute transport processes in the kidney, and/or for purinergic signaling. Variants found in other genes may compound this abnormality.
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Proteínas de Ligação ao Cálcio/genética , Sequenciamento do Exoma , Genes Mitocondriais , Variação Genética , Cálculos Renais/diagnóstico , Cálculos Renais/etiologia , Proteínas de Transporte da Membrana Mitocondrial/genética , Adolescente , Adulto , Idoso , Alelos , Sequência de Aminoácidos , Bancos de Espécimes Biológicos , Biomarcadores , Família , Feminino , Predisposição Genética para Doença , Genótipo , Humanos , Cálculos Renais/metabolismo , Masculino , Pessoa de Meia-Idade , Linhagem , Polimorfismo de Nucleotídeo Único , Conformação Proteica , Relação Estrutura-Atividade , Avaliação de Sintomas , Reino Unido , Adulto JovemRESUMO
Kidney stone disease (nephrolithiasis) is a common problem that can be associated with alterations in urinary solute composition including hypercalciuria. Studies suggest that the prevalence of monogenic kidney stone disorders, including renal tubular acidosis with deafness, Bartter syndrome, primary hyperoxaluria and cystinuria, in patients attending kidney stone clinics is â¼15%. However, for the majority of individuals, nephrolithiasis has a multifactorial aetiology involving genetic and environmental factors. Nonetheless, the genetic influence on stone formation in these idiopathic stone formers remains considerable and twin studies estimate a heritability of >45% for nephrolithiasis and >50% for hypercalciuria. The contribution of polygenic influences from multiple loci have been investigated by genome-wide association and candidate gene studies, which indicate that a number of genes and molecular pathways contribute to the risk of stone formation. Genetic approaches, studying both monogenic and polygenic factors in nephrolithiasis, have revealed that the following have important roles in the aetiology of kidney stones: transporters and channels; ions, protons and amino acids; the calcium-sensing receptor (a G protein-coupled receptor) signalling pathway; and the metabolic pathways for vitamin D, oxalate, cysteine, purines and uric acid. These advances, which have increased our understanding of the pathogenesis of nephrolithiasis, will hopefully facilitate the future development of targeted therapies for precision medicine approaches in patients with nephrolithiasis.
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Cálculos Renais/genética , Estudo de Associação Genômica Ampla , Humanos , Cálculos Renais/etiologiaRESUMO
Kidney stone disease (nephrolithiasis) is a major clinical and economic health burden with a heritability of ~45-60%. We present genome-wide association studies in British and Japanese populations and a trans-ethnic meta-analysis that include 12,123 cases and 417,378 controls, and identify 20 nephrolithiasis-associated loci, seven of which are previously unreported. A CYP24A1 locus is predicted to affect vitamin D metabolism and five loci, DGKD, DGKH, WDR72, GPIC1, and BCR, are predicted to influence calcium-sensing receptor (CaSR) signaling. In a validation cohort of only nephrolithiasis patients, the CYP24A1-associated locus correlates with serum calcium concentration and a number of nephrolithiasis episodes while the DGKD-associated locus correlates with urinary calcium excretion. In vitro, DGKD knockdown impairs CaSR-signal transduction, an effect rectified with the calcimimetic cinacalcet. Our findings indicate that studies of genotype-guided precision-medicine approaches, including withholding vitamin D supplementation and targeting vitamin D activation or CaSR-signaling pathways in patients with recurrent kidney stones, are warranted.
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Cálcio/metabolismo , Cálculos Renais/genética , Vitamina D/metabolismo , Adulto , Idoso , Povo Asiático/genética , Diacilglicerol Quinase/genética , Diacilglicerol Quinase/metabolismo , Feminino , Variação Genética , Estudo de Associação Genômica Ampla , Genótipo , Humanos , Japão , Cálculos Renais/metabolismo , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Estudos Prospectivos , Proteínas/genética , Proteínas/metabolismo , Receptores de Detecção de Cálcio/genética , Receptores de Detecção de Cálcio/metabolismo , Reino Unido , População Branca/genéticaRESUMO
Loss-of-function mutations of GNA11, which encodes G-protein subunit α11 (Gα11), a signaling partner for the calcium-sensing receptor (CaSR), result in familial hypocalciuric hypercalcemia type 2 (FHH2). FHH2 is characterized by hypercalcemia, inappropriately normal or raised parathyroid hormone (PTH) concentrations, and normal or low urinary calcium excretion. A mouse model for FHH2 that would facilitate investigations of the in vivo role of Gα11 and the evaluation of calcimimetic drugs, which are CaSR allosteric activators, is not available. We therefore screened DNA from > 10,000 mice treated with the chemical mutagen N-ethyl-N-nitrosourea (ENU) for GNA11 mutations and identified a Gα11 variant, Asp195Gly (D195G), which downregulated CaSR-mediated intracellular calcium signaling in vitro, consistent with it being a loss-of-function mutation. Treatment with the calcimimetic cinacalcet rectified these signaling responses. In vivo studies showed mutant heterozygous (Gna11+/195G) and homozygous (Gna11195G/195G) mice to be hypercalcemic with normal or increased plasma PTH concentrations and normal urinary calcium excretion. Cinacalcet (30mg/kg orally) significantly reduced plasma albumin-adjusted calcium and PTH concentrations in Gna11+/195G and Gna11195G/195G mice. Thus, our studies have established a mouse model with a germline loss-of-function Gα11 mutation that is representative for FHH2 in humans and demonstrated that cinacalcet can correct the associated abnormalities of plasma calcium and PTH.
Assuntos
Cinacalcete/uso terapêutico , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/efeitos dos fármacos , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/genética , Hipercalcemia/tratamento farmacológico , Mutação/efeitos dos fármacos , Administração Oral , Animais , Cálcio/sangue , Cálcio/urina , Cinacalcete/administração & dosagem , Modelos Animais de Doenças , Etilnitrosoureia/farmacologia , Feminino , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/química , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Modelos Moleculares , Hormônio Paratireóideo/sangue , Hormônio Paratireóideo/metabolismo , Receptores de Detecção de Cálcio/metabolismo , Alinhamento de Sequência , Análise de Sequência de DNA , Albumina Sérica , Transdução de SinaisRESUMO
Heterozygous germline gain-of-function mutations of G-protein subunit α11 (Gα11), a signaling partner for the calcium-sensing receptor (CaSR), result in autosomal dominant hypocalcemia type 2 (ADH2). ADH2 may cause symptomatic hypocalcemia with low circulating parathyroid hormone (PTH) concentrations. Effective therapies for ADH2 are currently not available, and a mouse model for ADH2 would help in assessment of potential therapies. We hypothesized that a previously reported dark skin mouse mutant (Dsk7) - which has a germline hypermorphic Gα11 mutation, Ile62Val - may be a model for ADH2 and allow evaluation of calcilytics, which are CaSR negative allosteric modulators, as a targeted therapy for this disorder. Mutant Dsk7/+ and Dsk7/Dsk7 mice were shown to have hypocalcemia and reduced plasma PTH concentrations, similar to ADH2 patients. In vitro studies showed the mutant Val62 Gα11 to upregulate CaSR-mediated intracellular calcium and MAPK signaling, consistent with a gain of function. Treatment with NPS-2143, a calcilytic compound, normalized these signaling responses. In vivo, NPS-2143 induced a rapid and marked rise in plasma PTH and calcium concentrations in Dsk7/Dsk7 and Dsk7/+ mice, which became normocalcemic. Thus, these studies have established Dsk7 mice, which harbor a germline gain-of-function Gα11 mutation, as a model for ADH2 and have demonstrated calcilytics as a potential targeted therapy.