Jan Halbritter
Research interests
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InterestsPediatric Nephrology, Glomerulonephritis, Renal Disease, Chronic Kidney Failure, Focal Segmental Glomerulosclerosis, Kidney Disease, Kidney Transplantation, Nephrotic Syndrome, Kidney, Hypertension
Publications
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4.64Impact points
MPA: A treatment option for lymphocytic colitis and mesalamine-induced interstitial nephritis.
Inflammatory bowel diseases. 12/2011; 18(3):E599-600.
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2.84Impact points
Effects of SLC10A2 variant rs9514089 on gallstone risk and serum cholesterol levels- meta-analysis of three independent cohorts.
BMC medical genetics. 11/2011; 12:149.
Recently, a single nucleotide polymorphism (SNP) rs9514089 in SLC10A2 (apical sodium-dependent bile acid transporter gene) has been identified as a susceptibility variant for cholelithiasis in humans. Here we assessed the effects of rs9514089 on gallstone risk and related phenotypes of the metabolic... [more] Recently, a single nucleotide polymorphism (SNP) rs9514089 in SLC10A2 (apical sodium-dependent bile acid transporter gene) has been identified as a susceptibility variant for cholelithiasis in humans. Here we assessed the effects of rs9514089 on gallstone risk and related phenotypes of the metabolic syndrome in the self-contained population of Sorbs (183 cases with gallstones/826 controls). Furthermore, we performed a meta-analysis for effects of rs9514089 on susceptibility for cholelithiasis in three independent cohorts (Stuttgart: 56 cases/71 controls, Aachen: 184 cases/184 controls and Sorbs). There was no significant association of rs9514089 with gallstone risk, serum lipid parameters and BMI in the Sorbs and in the meta-analysis of all three cohorts (p > 0.05). There was an effect trend in the subgroup of lean subjects but based on different effect directions in the three cohorts there was no significant association in the meta-analysis. We were not able to replicate the effect of rs9514089 on gallstone risk in the Sorbs. Further analyses in larger cohorts are required to finally assess the role of genetic variants in SLC10A2 in human gallstone development and lipid metabolism.
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3.50Impact points
Successful simultaneous pancreas kidney transplantation in maturity-onset diabetes of the young type 5.
Transplantation. 10/2011; 92(8):e45-7.
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3.89Impact points
Role of genetic variation in the human sodium-glucose cotransporter 2 gene (SGLT2) in glucose homeostasis.
Pharmacogenomics. 08/2011; 12(8):1119-26.
Mutations in the sodium-glucose cotransporter 2 (SGLT2), as well as treatment with SGLT2 inhibitors result in reduced fasting glucose levels, HbA(1c) and BMI. We therefore investigated the effects of common genetic variation in SGLT2 on human Type 2 diabetes and related traits. Four HapMap tagging S... [more] Mutations in the sodium-glucose cotransporter 2 (SGLT2), as well as treatment with SGLT2 inhibitors result in reduced fasting glucose levels, HbA(1c) and BMI. We therefore investigated the effects of common genetic variation in SGLT2 on human Type 2 diabetes and related traits. Four HapMap tagging SNPs covering the common genetic variation in SGLT2 (r² > 0.8 and minor allele frequency > 0.01) were genotyped for subsequent association studies on BMI, Type 2 diabetes and related metabolic traits in 1013 Sorbs (Germany). An independent cohort from Berlin (n = 2042) was taken for replication. The rs9934336 G-allele was nominally associated with increased 30-min plasma glucose, 120-min insulin concentrations and AUC120min(glucose) during oral glucose tolerance test in 907 nondiabetic Sorbs (p < 0.05). In the combined analysis including the Sorbs and the Berlin cohort, rs9934336 was nominally associated with 120-min insulin concentrations (adjusted p < 0.05) in nondiabetic subjects (n = 2590). Our data suggest a role of SGLT2 genetic variation in the regulation of glucose homeostasis and promote pharmacogenomic studies to clarify the efficacy of antidiabetic treatment by SGLT2 inhibitors.
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4.41Impact points
Genetic and evolutionary analyses of the human bone morphogenetic protein receptor 2 (BMPR2) in the pathophysiology of obesity.
PloS one. 01/2011; 6(2):e16155.
Human bone morphogenetic protein receptor 2 (BMPR2) is essential for BMP signalling and may be involved in the regulation of adipogenesis. The BMPR2 locus has been suggested as target of recent selection in human populations. We hypothesized that BMPR2 might have a role in the pathophysiology of obe... [more] Human bone morphogenetic protein receptor 2 (BMPR2) is essential for BMP signalling and may be involved in the regulation of adipogenesis. The BMPR2 locus has been suggested as target of recent selection in human populations. We hypothesized that BMPR2 might have a role in the pathophysiology of obesity. Evolutionary analyses (dN/dS, Fst, iHS) were conducted in vertebrates and human populations. BMPR2 mRNA expression was measured in 190 paired samples of visceral and subcutaneous adipose tissue. The gene was sequenced in 48 DNA samples. Nine representative single nucleotide polymorphisms (SNPs) were genotyped for subsequent association studies on quantitative traits related to obesity in 1830 German Caucasians. An independent cohort of 925 Sorbs was used for replication. Finally, relation of genotypes to mRNA in fat was examined. The evolutionary analyses indicated signatures of selection on the BMPR2 locus. BMPR2 mRNA expression was significantly increased both in visceral and subcutaneous adipose tissue of 37 overweight (BMI>25 and <30 kg/m²) and 80 obese (BMI>30 kg/m²) compared with 44 lean subjects (BMI< 25 kg/m²) (P<0.001). In a case-control study including lean and obese subjects, two intronic SNPs (rs6717924, rs13426118) were associated with obesity (adjusted P<0.05). Combined analyses including the initial cohort and the Sorbs confirmed a consistent effect for rs6717924 (combined P = 0.01) on obesity. Moreover, rs6717924 was associated with higher BMPR2 mRNA expression in visceral adipose tissue. Combined BMPR2 genotype-phenotype-mRNA expression data as well as evolutionary aspects suggest a role of BMPR2 in the pathophysiology of obesity.
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0.34Impact points
[Interstitial nephritis.]
Der Internist. 09/2009;
Drugs such as antibiotics, non-steroidal anti-inflammatory drugs and proton pump inhibitors, infections and systemic diseases can trigger interstitial nephritis. The clinical outcome varies from asymptomatic progression to acute kidney injury. Interstitial nephritis often leads to characteristic and... [more] Drugs such as antibiotics, non-steroidal anti-inflammatory drugs and proton pump inhibitors, infections and systemic diseases can trigger interstitial nephritis. The clinical outcome varies from asymptomatic progression to acute kidney injury. Interstitial nephritis often leads to characteristic and detectable partial tubular disorders such as tubular proteinuria (alpha(1)-microglobulin), phosphaturia with hypophosphatemia, aminoaciduria, diminished H(+) secretion with metabolic acidosis with inadequate high urinary pH, glucosuria and salt loss. The main principle of treatment is avoidance of the inducing agent. In addition corticosteroids have been proven usable after exclusion of an infection so that a good prognosis can be expected for acute nephritis in the majority of cases. In chronic forms the interstitial nephritis involves the glomeruli as well as potentially resulting in end-stage renal failure in the long run. Supportive therapies are then required in the sense of chronic renal failure in order to prevent further functional loss up to end-stage renal disease.
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2.65Impact points
Isolated renal relapse of sarcoidosis under low-dose glucocorticoid therapy.
Journal of general internal medicine : official journal of the Society for Research and Education in Primary Care Internal Medicine. 07/2008; 23(6):879-82.
Sarcoidosis is a multisystem disease of unknown etiology. Renal manifestation is rare and usually caused by hypercalcemia and nephrocalcinosis. Moreover, renal disease can occur as granulomatous interstitial nephritis (GIN), which is a histological diagnosis. We describe a case of sarcoidosis first ... [more] Sarcoidosis is a multisystem disease of unknown etiology. Renal manifestation is rare and usually caused by hypercalcemia and nephrocalcinosis. Moreover, renal disease can occur as granulomatous interstitial nephritis (GIN), which is a histological diagnosis. We describe a case of sarcoidosis first presenting with multiple organ involvement including renal failure caused by severe GIN and subsequent remission on glucocorticoid therapy. After 18 months under low-dose prednisolone, the patient was readmitted with acute renal failure, histologically confirmed to be a relapse of renal sarcoidosis. Extrarenal manifestations of sarcoidosis were not present. Glucocorticoid dose was raised and kidney function again recovered significantly. Usual serologic markers of disease activity were not appropriate to indicate disease activity. Renal manifestation of sarcoidosis should be diagnosed by renal biopsy to guide therapy and probably requires larger glucocorticoid doses and prolonged treatment to prevent relapse.
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2.59Impact points
Phenotype of a patient with a de novo mutation in the hepatocyte nuclear factor 1beta/maturity-onset diabetes of the young type 5 gene.
Metabolism: clinical and experimental. 04/2008; 57(3):416-20.
Mutations in the gene encoding the transcription factor hepatocyte nuclear factor (HNF) 1beta cause various phenotypes including maturity-onset diabetes of the young type 5 (MODY5) and kidney disease. We provide molecular and pathophysiologic characterization of a 23-year-old male patient with clini... [more] Mutations in the gene encoding the transcription factor hepatocyte nuclear factor (HNF) 1beta cause various phenotypes including maturity-onset diabetes of the young type 5 (MODY5) and kidney disease. We provide molecular and pathophysiologic characterization of a 23-year-old male patient with clinical presentation typical for MODY5 with renal involvement. Clinical studies (including intravenous glucose tolerance test and magnetic resonance imaging) of the patient and 5 family members in comparison with unrelated control subjects and molecular analysis of the HNF-1beta gene (direct sequencing, paternity testing, and restriction fragment length polymorphism analysis for parental mosaicism) were performed. The patient was born with low birth weight (2250 g), whereas his dizygotic twin sister was of normal weight (3500 g) and healthy. He had cystic renal dysplasia with progressive renal failure and pancreas atrophy with beta-cell dysfunction and early-onset diabetes mellitus but no family history of diabetes. Intravenous glucose tolerance test showed a markedly reduced but not absent acute insulin response compared with controls (n = 6). A mutation in the HNF-1beta gene S148L (C443T) in exon 2 within the pseudo-POU domain was identified. All other family members and the control group (n = 255) did not have the mutation, suggesting that we described a de novo mutation in HNF-1beta. Paternity was confirmed, and no signs of mosaicism in DNA analysis of both parents could be detected. Of note, the low birth weight of the patient in contrast to his healthy twin sister provides interesting support for the fetal insulin hypothesis for reduced birth weight.
Following (1)
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Christof Mayer
Handelshochschule Leipzig
Topics (3)
