Henning Wittenburg

Publications of Henning Wittenburg

• A common variant of PNPLA3 (p.I148M) is not associated with alcoholic chronic pancreatitis.

  Authors: Jonas Rosendahl, Anke Tönjes, Dorit Schleinitz, Peter Kovacs, Johannes Wiegand, Claudia Ruffert, Moritz Jesinghaus, Robert Schober, Max Herms, Robert Grützmann [......] Michael Stumvoll, Stephan Böhm, Thomas Berg, Henning Wittenburg, Joachim Mössner, Rene te Morsche, Monique Derikx, Volker Keim, Heiko Witt, Joost P H Drenth

  PloS one. 01/2012; 7(1):e29433.

  Chronic pancreatitis (CP) is an inflammatory disease that in some patients leads to exocrine and endocrine dysfunction. In industrialized countries the most common aetiology is chronic alcohol abuse.Chronic pancreatitis (CP) is an inflammatory disease that in some patients leads to exocrine and endocrine dysfunction. In industrialized countries the most common aetiology is chronic alcohol abuse. Descriptions of associated genetic alterations in alcoholic CP are rare. However, a common PNPLA3 variant (p.I148M) is associated with the development of alcoholic liver cirrhosis (ALC). Since, alcoholic CP and ALC share the same aetiology PNPLA3 variant (p.I148M) possibly influences the development of alcoholic CP. Using melting curve analysis we genotyped the variant in 1510 patients with pancreatitis or liver disease (961 German and Dutch alcoholic CP patients, 414 German patients with idiopathic or hereditary CP, and 135 patients with ALC). In addition, we included in total 2781 healthy controls in the study. The previously published overrepresentation of GG-genotype was replicated in our cohort of ALC (p-value <0.0001, OR 2.3, 95% CI 1.6-3.3). Distributions of genotype and allele frequencies of the p.I148M variant were comparable in patients with alcoholic CP, idiopathic and hereditary CP and in healthy controls. The absence of an association of PNPLA3 p.I148M with alcoholic CP seems not to point to a common pathway in the development of alcoholic CP and alcoholic liver cirrhosis.

• Effects of SLC10A2 variant rs9514089 on gallstone risk and serum cholesterol levels- meta-analysis of three independent cohorts.

  Authors: Anke Tönjes, Henning Wittenburg, Jan Halbritter, Olga Renner, Simone Harsch, Eduard F Stange, Frank Lammert, Michael Stumvoll, Peter Kovacs

  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 inRecently, 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.

• Hereditary liver disease: gallstones.

  Authors: Henning Wittenburg

  Best practice & research. Clinical gastroenterology. 10/2010; 24(5):747-56.

  Gallstones are common in Western countries and due to pain and complications pose a substantial burden on health care systems. In general, cholesterol gallstones are distinguished from bilirubinGallstones are common in Western countries and due to pain and complications pose a substantial burden on health care systems. In general, cholesterol gallstones are distinguished from bilirubin gallstones. Bilirubin gallstones form if the ion product of unconjugated bilirubin and calcium in gallbladder bile exceeds the solubilisation capacities of mixed micelles and vesicles. Cholesterol gallstones develop if the amount of cholesterol in gallbladder bile exceeds the maximum concentration that is soluble at the given concentration of bile salts and phospholipids. In addition, cholesterol gallstone formation requires hypomotility of the gallbladder and a mucin gel as nucleation matrix for monohydrate crystals. The individual risk of gallstone formation is determined by interactions of lithogenic alleles of gallstone susceptibility genes and multiple environmental factors. For asymptomatic gallstones, expectant management is recommended, whereas an episode of gallstone-associated pain substantially increases the risk of complications such as cholecystitis, cholangitis and pancreatitis and therefore necessitates cholecystectomy.

• Sequence analysis of the human tyrosylprotein sulfotransferase-2 gene in subjects with chronic pancreatitis.

  Authors: Jonas Rosendahl, Zsolt Rónai, Peter Kovacs, Niels Teich, Henning Wittenburg, Matthias Blüher, Michael Stumvoll, Joachim Mössner, Volker Keim, Andrew R M Bradbury, Miklós Sahin-Tóth

  Pancreatology : official journal of the International Association of Pancreatology (IAP) ... [et al.]. 01/2010; 10(2-3):165-72.

  Human trypsinogens are post-translationally sulfated on Tyr154 by the Golgi resident enzyme tyrosylprotein sulfotransferase-2 (TPST2). Tyrosine sulfation stimulates the autoactivation of humanHuman trypsinogens are post-translationally sulfated on Tyr154 by the Golgi resident enzyme tyrosylprotein sulfotransferase-2 (TPST2). Tyrosine sulfation stimulates the autoactivation of human cationic trypsinogen. Because increased trypsinogen autoactivation has been implicated as a pathogenic mechanism in chronic pancreatitis, we hypothesized that genetic variants of TPST2 might alter the risk for the disease. We sequenced the 4 protein-coding exons and the adjacent intronic sequences of TPST2 in 151 subjects with chronic pancreatitis and in 169 healthy controls. The functional effect of TPST2 variants on trypsinogen sulfation was analyzed in transfected HEK 293T cells. We detected 10 common polymorphic variants, including 6 synonymous variants and 4 intronic variants, with similar frequencies in patients and controls. None of the 8 common haplotypes reconstructed from the frequent variants showed an association with chronic pancreatitis. In addition, we identified 5 rare TPST2 variants, which included 3 synonymous alterations, the c.458G>A (p.R153H) nonsynonymous variant and the c.-9C>T variant in the 5' untranslated region. The p.R153H variant was found in a family with hereditary pancreatitis; however, it did not segregate with the disease. In functional assays, both the p.R153H and c.-9C>T TPST2 variants catalyzed trypsinogen sulfation as well as wild-type TPST2. Genetic variants of human TPST2 exert no influence on the risk of chronic pancreatitis.

• Complete analysis of the human mesotrypsinogen gene (PRSS3) in patients with chronic pancreatitis.

  Authors: Jonas Rosendahl, Niels Teich, Peter Kovacs, Richard Szmola, Matthias Blüher, Thomas M Gress, Albrecht Hoffmeister, Volker Keim, Matthias Löhr, Joachim Mössner, Renate Nickel, Johann Ockenga, Roland Pfützer, Hans-Ulrich Schulz, Michael Stumvoll, Henning Wittenburg, Miklós Sahin-Tóth, Heiko Witt

  Pancreatology : official journal of the International Association of Pancreatology (IAP) ... [et al.]. 01/2010; 10(2-3):243-9.

  A sustained imbalance of pancreatic proteases and their inhibitors seems to be important for the development of chronic pancreatitis (CP). Mesotrypsin (PRSS3) can degrade intrapancreatic trypsinA sustained imbalance of pancreatic proteases and their inhibitors seems to be important for the development of chronic pancreatitis (CP). Mesotrypsin (PRSS3) can degrade intrapancreatic trypsin inhibitors that protect against CP. Genetic variants that cause higher mesotrypsin activity might increase the risk for CP. We analyzed all 5 exons and the adjacent non-coding sequences of PRSS3 by direct sequencing of 313 CP patients and 327 controls. Additionally, exon 4 was investigated in 855 patients and 1,294 controls and a c.454+191G>A variant in 855 patients and 1,467 controls. The c.499A>G (p.T167A) variant was analyzed functionally using transiently transfected HEK 293T cells. In the exonic regions, the previously described common c.94_96delGAG (p.E32del) variant and a novel p.T167A non-synonymous alteration were identified. Extended analysis of the p.T167A variant revealed no association to CP and in functional assays p.T167A showed normal secretion and activity. Variants of the intronic regions, including the extensively analyzed c.454+191G>A alteration, were not associated with the disease. Haplotype reconstruction using variants with a minor allele frequency of >1% revealed no CP-associated haplotype. Although the trypsin inhibitor-degrading activity qualified PRSS3 as a candidate for a novel CP susceptibility gene, we found no association between a specific variant or haplotype and CP in our cohort with a high suspicion of genetically determined disease.

• Budd Chiari syndrome without evidence for thrombosis. Is it still a Budd Chiari ?

  Authors: Sebastian Weis, Christian Wittekind, Christoph Benckert, Joachim Mössner, Henning Wittenburg

  Annals of hepatology : official journal of the Mexican Association of Hepatology. 09/2009; 8(4):388-389.

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• A Variant of the SLC10A2 Gene Encoding the Apical Sodium-Dependent Bile Acid Transporter Is a Risk Factor for Gallstone Disease.

  Authors: Olga Renner, Simone Harsch, Elke Schaeffeler, Stefan Winter, Matthias Schwab, Marcin Krawczyk, Jonas Rosendahl, Henning Wittenburg, Frank Lammert, Eduard F Stange

  PloS one. 01/2009; 4(10):e7321.

  BACKGROUND: Cholelithiasis is a multifactorial process and several mechanisms of gallstone formation have been postulated. As one of these mechanisms, a decreased expression of the ileal apicalBACKGROUND: Cholelithiasis is a multifactorial process and several mechanisms of gallstone formation have been postulated. As one of these mechanisms, a decreased expression of the ileal apical sodium-dependent bile acid transporter gene SLC10A2 in gallstone carriers was described previously. In this study the SLC10A2 gene was investigated to identify novel genetic variants and their association with gallstone formation. METHODOLOGY/PRINCIPAL FINDINGS: Study subjects were selected with the presence or absence of gallstones confirmed by ultrasound and medical history. Genomic DNA was obtained from blood leukocytes. Sequence analysis was performed of all six exonic and flanking regions as well as of 2,400 base pairs of the SLC10A2 promoter in a cohort of gallstone carriers and control subjects from Stuttgart, Germany. Genotype frequencies of newly identified genetic variants (n = 6) and known single nucleotide polymorphisms (n = 24) were established using MALDI-TOF mass spectrometry. Six new genetic variants were found within the SLC10A2 gene. Although none of the variants was linked to gallstone disease in the Stuttgart cohort overall, the minor allele of SNP rs9514089 was more prevalent in male non-obese gallstone carriers (p = 0.06680, OR = 11.00). In a separate population from Aachen, Germany, the occurrence of rs9514089 was two-fold higher in gallstone patients (22%) than in corresponding controls (11%) (p = 0.00995, OR = 2.19). In the pooled Aachen/Stuttgart cohort rs9514089 was highly significantly linked to cholelithiasis (p = 0.00767, OR = 2.04). A more frequent occurrence was observed for male gallstone carriers (22%) compared to controls (9%) (p = 0.01017, OR = 2.99), for the total normal weight group (p = 0.00754, OR = 2.90), and for male non-obese gallstone patients (p = 0.01410, OR = 6.85). Moreover, for the minor allele of rs9514089 an association with low plasma cholesterol levels was found especially in gallstone carriers (p = 0.05). CONCLUSIONS/SIGNIFICANCE: We have identified SLC10A2 as a novel susceptibility gene for cholelithiasis in humans. Comprehensive statistical analysis provides strong evidence that rs9514089 is a genetic determinant especially in male non-obese gallstone carriers. The minor allele of rs9514089 is related to differences in plasma cholesterol levels among the subjects.

• The hole in the stomach.

  Authors: Hans Bödeker, Steffen Leinung, Henning Wittenburg, Julia Fischer, Ingolf Schiefke, Niels Teich

  Diagnostic and therapeutic endoscopy. 02/2008; 2008:257185.

  A 57 year old woman was presented to the emergency department with upper abdominal pain and left sided chest discomfort. No cardiac or pulmonary cause could be determined and the patient underwentA 57 year old woman was presented to the emergency department with upper abdominal pain and left sided chest discomfort. No cardiac or pulmonary cause could be determined and the patient underwent upper gastrointestinal endoscopy. Inversion of the scope to the fundus and subsequent fluoroscopy revealed a diaphragmatic hernia with a large herniation of the gastric fundus. Immediate laparotomy showed a 3 cm orifice of the diaphragm. The orifice was widened and a partial necrosis of the incarcerated fundus was resected. The patient recovered fully and was discharged 12 days after laparotomy.

• Variation of the gene encoding the nuclear bile salt receptor FXR and gallstone susceptibility in mice and humans.

  Authors: Peter Kovacs, Rahel Kress, Jacqueline Rocha, Ulrike Kurtz, Juan Francisco Miquel, Flavio Nervi, Nahum Méndez-Sánchez, Misael Uribe, Hans H Bock, Ramin Schirin-Sokhan, Michael Stumvoll, Joachim Mössner, Frank Lammert, Henning Wittenburg

  Journal of hepatology. 01/2008; 48(1):116-24.

  BACKGROUND/AIMS: From quantitative trait locus mapping in inbred mice, we identified the Nr1h4 gene encoding the nuclear bile salt receptor FXR as a candidate gene for the cholesterol gallstoneBACKGROUND/AIMS: From quantitative trait locus mapping in inbred mice, we identified the Nr1h4 gene encoding the nuclear bile salt receptor FXR as a candidate gene for the cholesterol gallstone susceptibility locus Lith7. Here, we investigated further an association of the gene encoding FXR and gallstone susceptibility in mice and humans. METHODS: The Nr1h4 gene was sequenced in inbred mouse strains with susceptible and resistant Lith7 alleles. Quantitative RT-PCR was employed to determine mRNA expression levels. Gallstone carriers and control subjects of three different populations comprising 1004 individuals were genotyped for polymorphisms of the orthologous human gene detected by sequencing. RESULTS: Expression and sequence analyses in inbred mice were consistent with Nr1h4 underlying Lith7. In the human populations, we identified three frequent haplotypes that accounted for > 95% of all haplotypes observed. In a Mexican population, the most common haplotype NR1H4_1 was associated with gallstone prevalence. In contrast, NR1H4_1 displayed no association with gallstone prevalence in a German population, whereas in a Chilean population we observed a trend towards a protective effect of NR1H4_1. CONCLUSIONS: Our study in an inbred mouse model and in three ethnically distinct populations indicates complex interactions of NR1H4 alleles and other risk factors for the development of cholelithiasis.

• Genetic predisposition to gallbladder stones.

  Authors: Henning Wittenburg, Frank Lammert

  Seminars in liver disease. 03/2007; 27(1):109-21.

  Geographic and ethnic differences in gallstone prevalence rates and familial clustering of cholelithiasis imply that genetic factors influence the risk of gallstone formation. Recently, twin, family,Geographic and ethnic differences in gallstone prevalence rates and familial clustering of cholelithiasis imply that genetic factors influence the risk of gallstone formation. Recently, twin, family, and linkage studies confirmed a genetic predisposition to the development of symptomatic gallstones. In rare instances, mutations in single genes confer a substantial risk for the formation of gallstones. However, in the majority of cases gallstones might develop as a result of lithogenic polymorphisms in several genes and their interactions with multiple environmental factors, rendering gallstones generally a complex genetic disorder. Some of the rare monogenic forms of cholelithiasis were unraveled but the lithogenic genes that increase the susceptibility to cholelithiasis in the majority of gallstone carriers remain elusive. Identification of these lithogenic genes will provide novel means of risk assessment, strategies for prevention, and targets for nonsurgical management of cholelithiasis, which currently is one of the most expensive digestive disorders.

• Cholesterol gallstone susceptibility loci: a mouse map, candidate gene evaluation, and guide to human LITH genes.

  Authors: Malcolm A Lyons, Henning Wittenburg

  Gastroenterology. 01/2007; 131(6):1943-70.

• Susceptibility to cholesterol gallstone formation: evidence that LITH genes also encode immune-related factors.

  Authors: Malcolm A Lyons, Henning Wittenburg

  Biochimica et biophysica acta. 11/2006; 1761(10):1133-47.

  Cholesterol gallstones are solid calculi that form in the gallbladder from bile constituents and chiefly comprise cholesterol. Cholesterol gallstones are prevalent and costly for healthcare systems.Cholesterol gallstones are solid calculi that form in the gallbladder from bile constituents and chiefly comprise cholesterol. Cholesterol gallstones are prevalent and costly for healthcare systems. In addition to various environmental factors, genetic risk contributes substantially to gallstone susceptibility. Candidate gene approaches to identify contributory genes are based on prior knowledge of gene-protein function. Whether selected from the entire genome or from limited genomic regions detected by experimental linkage analyses, thus far, candidate genes predominantly were related to lipid homeostasis. Alternatively, comprehensive review of available data suggests that a fundamental driving force underlying cholesterol gallstone formation is inflammation. Therefore, we predict that Lith genes in mice and LITH genes in humans also encode inflammatory molecules, their receptors and other mediators. Indeed, many Lith loci, defined experimentally using inbred mouse models, co-localise with genes that encode inflammation-related proteins. Systematic review of the literature reveals evidence consistent with inflammatory responses that may dictate each of the three cornerstones of cholesterol gallstone formation: biliary cholesterol supersaturation; cholesterol nucleation; gallbladder hypomotility. Genetically targeted inbred mice represent a powerful tool to interrogate the relationship between immune-related genes and gallstone susceptibility. We urge researchers to consider inflammation-related genes when designing population case-control genetic association studies pertaining to the genetic basis of gallstones. Immune and inflammatory events underlie each criterion necessary for cholesterol gallstone formation, which suggests that variation within the respective genes is fundamental for gallstone formation. In turn, inflammatory mediators may exert a spectrum of effects in response to genetic variation within lipid homeostatic genes.

• Percutaneous transgastric irrigation drainage in combination with endoscopic necrosectomy in necrotizing pancreatitis (with videos).

  Authors: Susanne Raczynski, Niels Teich, Gudrun Borte, Henning Wittenburg, Joachim Mössner, Karel Caca

  Gastrointestinal endoscopy. 10/2006; 64(3):420-4.

  BACKGROUND: Endoscopic drainage of pancreatic acute and chronic pseudocysts and pancreatic necrosectomy have been shown to be beneficial for critically ill patients, with complete endoscopicBACKGROUND: Endoscopic drainage of pancreatic acute and chronic pseudocysts and pancreatic necrosectomy have been shown to be beneficial for critically ill patients, with complete endoscopic resolution rates of around 80%. OBJECTIVE: Our purpose was to describe an improved endoscopic technique used to treat pancreatic necrosis. DESIGN: Case report. SETTING: University hospital. PATIENTS AND INTERVENTIONS: Two patients with large retroperitoneal necroses were treated with percutaneous transgastric retroperitoneal flushing tubes and a percutaneous transgastric jejunal feeding tube by standard percutaneous endoscopic gastrostomy access in addition to endoscopic necrosectomy. RESULTS: Intensive percutaneous transgastric flushing in combination with percutaneous normocaloric enteral nutrition and repeated endoscopic necrosectomy led to excellent outcomes in both patients. LIMITATIONS: Small number of patients. CONCLUSIONS: The "double percutaneous endoscopic gastrostomy" approach for simultaneous transgastric drainage and normocaloric enteral nutrition in severe cases of pancreatic necroses is safe and effective. It could be a promising improvement to endoscopic transgastric treatment options in necrotizing pancreatitis.

• QTL mapping for genetic determinants of lipoprotein cholesterol levels in combined crosses of inbred mouse strains.

  Authors: Henning Wittenburg, Malcolm A Lyons, Renhua Li, Ulrike Kurtz, Xiaosong Wang, Joachim Mössner, Gary A Churchill, Martin C Carey, Beverly Paigen

  Journal of lipid research. 09/2006; 47(8):1780-90.

  To identify additional loci that influence lipoprotein cholesterol levels, we performed quantitative trait locus (QTL) mapping in offspring of PERA/EiJxI/LnJ and PERA/EiJxDBA/2J intercrosses and in aTo identify additional loci that influence lipoprotein cholesterol levels, we performed quantitative trait locus (QTL) mapping in offspring of PERA/EiJxI/LnJ and PERA/EiJxDBA/2J intercrosses and in a combined data set from both crosses after 8 weeks of consumption of a high fat-diet. Most QTLs identified were concordant with homologous chromosomal regions that were associated with lipoprotein levels in human studies. We detected significant new loci for HDL cholesterol levels on chromosome (Chr) 5 (Hdlq34) and for non-HDL cholesterol levels on Chrs 15 (Nhdlq9) and 16 (Nhdlq10). In addition, the analysis of combined data sets identified a QTL for HDL cholesterol on Chr 17 that was shared between both crosses; lower HDL cholesterol levels were conferred by strain PERA. This QTL colocalized with a shared QTL for cholesterol gallstone formation detected in the same crosses. Haplotype analysis narrowed this QTL, and sequencing of the candidate genes Abcg5 and Abcg8 confirmed shared alleles in strains I/LnJ and DBA/2J that differed from the alleles in strain PERA/EiJ. In conclusion, our analysis furthers the knowledge of genetic determinants of lipoprotein cholesterol levels in inbred mice and substantiates the hypothesis that polymorphisms of Abcg5/Abcg8 contribute to individual variation in both plasma HDL cholesterol levels and susceptibility to cholesterol gallstone formation.

• Association of a lithogenic Abcg5/Abcg8 allele on Chromosome 17 (Lith9) with cholesterol gallstone formation in PERA/EiJ mice.

  Authors: Henning Wittenburg, Malcolm A Lyons, Renhua Li, Ulrike Kurtz, Joachim Mössner, Gary A Churchill, Martin C Carey, Beverly Paigen

  Mammalian genome : official journal of the International Mammalian Genome Society. 08/2005; 16(7):495-504.

  To examine further the genetic determinants of cholesterol gallstone susceptibility in inbred mice, we performed quantitative trait locus (QTL) analysis of an intercross of gallstone-susceptibleTo examine further the genetic determinants of cholesterol gallstone susceptibility in inbred mice, we performed quantitative trait locus (QTL) analysis of an intercross of gallstone-susceptible PERA/EiJ and gallstone-resistant DBA/2J inbred mice. Three hundred twenty-four F2 offspring were phenotyped for cholelithiasis during consumption of a lithogenic diet and genotyped using microsatellite markers. Linkage analysis was performed by interval mapping. In addition, we analyzed the combined datasets from this cross and from an independent cross of strain PERA and gallstone-resistant I/Ln mice. QTL mapping detected one significant new gallstone susceptibility (Lith) locus on Chromosome 13 (Lith15). A second significant QTL on Chr 6 (Lith16) confirmed a previous QTL. Furthermore, suggestive QTLs confirmed Lith loci from previous crosses on Chromosomes 1, 2, 5, 16 and X. QTL analysis of the dataset derived from the combined crosses increased the detection power and narrowed confidence intervals of Lith loci on Chromosomes 2, 6, 13, and 16. Moreover, the analysis of combined datasets revealed a shared QTL between both crosses on Chromosome 17 (Lith9). Significantly higher mRNA expression of Abcg5 and Abcg8 in strain PERA compared with strains I/Ln and DBA/2 further substantiated that the PERA allele of Abcg5/Abcg8 was responsible for lithogenicity underlying Lith9.

• Combining data from multiple inbred line crosses improves the power and resolution of quantitative trait loci mapping.

  Authors: Renhua Li, Malcolm A Lyons, Henning Wittenburg, Beverly Paigen, Gary A Churchill

  Genetics. 04/2005; 169(3):1699-709.

  Rodent inbred line crosses are widely used to map genetic loci associated with complex traits. This approach has proven to be powerful for detecting quantitative trait loci (QTL); however, theRodent inbred line crosses are widely used to map genetic loci associated with complex traits. This approach has proven to be powerful for detecting quantitative trait loci (QTL); however, the resolution of QTL locations, typically approximately 20 cM, means that hundreds of genes are implicated as potential candidates. We describe analytical methods based on linear models to combine information available in two or more inbred line crosses. Our strategy is motivated by the hypothesis that common inbred strains of the laboratory mouse are derived from a limited ancestral gene pool and thus QTL detected in multiple crosses are likely to represent shared ancestral polymorphisms. We demonstrate that the combined-cross analysis can improve the power to detect weak QTL, can narrow support intervals for QTL regions, and can be used to separate multiple QTL that colocalize by chance. Moreover, combined-cross analysis can establish the allelic states of a QTL among a set of parental lines, thus providing critical information for narrowing QTL regions by haplotype analysis.

• Quantitative trait loci that determine lipoprotein cholesterol levels in an intercross of 129S1/SvImJ and CAST/Ei inbred mice.

  Authors: Malcolm A Lyons, Henning Wittenburg, Renhua Li, Kenneth A Walsh, Ron Korstanje, Gary A Churchill, Martin C Carey, Beverly Paigen

  Physiological genomics. 04/2004; 17(1):60-8.

  To identify genetic determinants of lipoprotein levels, we are performing quantitative trait locus (QTL) analysis on a series of mouse intercrosses in a "daisy chain" experimental design, to increaseTo identify genetic determinants of lipoprotein levels, we are performing quantitative trait locus (QTL) analysis on a series of mouse intercrosses in a "daisy chain" experimental design, to increase the power of detecting QTL and to identify common variants that should segregate in multiple intercrosses. In this study, we intercrossed strains CAST/Ei and 129S1/SvImJ, determined HDL, total, and non-HDL cholesterol levels, and performed QTL mapping using Pseudomarker software. For HDL cholesterol, we identified two significant QTL on chromosome (Chr) 1 (Hdlq5, 82 cM, 60-100 cM) and Chr 4 (Hdlq10, 20 cM, 10-30 cM). For total cholesterol, we identified three significant QTL on Chr 1 (Chol7, 74 cM, 65-80 cM), Chr 4 (Chol8, 12 cM, 0-30 cM), and Chr 17 (Chol9, 54 cM, 20-60 cM). For non-HDL cholesterol, we identified significant QTL on Chr 8 (Nhdlq1, 34 cM, 20-60 cM) and Chr X (Nhdlq2, 6 cM, 0-18 cM). Hdlq10 was the only QTL detected in two intercrosses involving strain CAST/Ei. Hdlq5, Hdlq10, Nhdlq1, and two suggestive QTL at D7Mit246 and D15Mit115 coincided with orthologous human lipoprotein QTL. Our analysis furthers the knowledge of the genetic control of lipoprotein levels and points to the importance of Hdlq10, which was detected repeatedly in multiple studies.

• Lith6: a new QTL for cholesterol gallstones from an intercross of CAST/Ei and DBA/2J inbred mouse strains.

  Authors: Malcolm A Lyons, Henning Wittenburg, Renhua Li, Kenneth A Walsh, Monika R Leonard, Ron Korstanje, Gary A Churchill, Martin C Carey, Beverly Paigen

  Journal of lipid research. 10/2003; 44(9):1763-71.

  A complex genetic basis determines the individual predisposition to develop cholesterol gallstones in response to environmental factors. We employed quantitative trait locus/loci (QTL) analyses of anA complex genetic basis determines the individual predisposition to develop cholesterol gallstones in response to environmental factors. We employed quantitative trait locus/loci (QTL) analyses of an intercross between inbred strains CAST/Ei (susceptible) and DBA/2J (resistant) to determine the subset of gallstone susceptibility (Lith) genes these strains possess. Parental and first filial generation mice of both genders and male intercross offspring were evaluated for gallstone formation after feeding a lithogenic diet. Linkage analysis was performed using a form of multiple interval mapping. One significant QTL colocalized with Lith1 [chromosome (chr) 2, 50 cM], a locus identified previously. Significantly, new QTL were detected and named Lith10 (chr 6, 4 cM), Lith6 (chr 6, 54 cM), and Lith11 (chr 8, 58 cM). Statistical and genetic analyses suggest that Lith6 comprises two QTL in close proximity. Our molecular and genetic data support the candidacy of peroxisome proliferator-activated receptor gamma (Pparg) and Slc21a1, encoding Pparg, and the basolateral bile acid transporter SLC21A1 (Slc21a1/Oatp1), respectively, as genes underlying Lith6.

• FXR and ABCG5/ABCG8 as determinants of cholesterol gallstone formation from quantitative trait locus mapping in mice.

  Authors: Henning Wittenburg, Malcolm A Lyons, Renhua Li, Gary A Churchill, Martin C Carey, Beverly Paigen

  Gastroenterology. 09/2003; 125(3):868-81.

  BACKGROUND & AIMS: Cholesterol gallstone formation is a complex genetic trait. To identify additional cholesterol gallstone susceptibility loci, we performed a quantitative trait locus analysis usingBACKGROUND & AIMS: Cholesterol gallstone formation is a complex genetic trait. To identify additional cholesterol gallstone susceptibility loci, we performed a quantitative trait locus analysis using an intercross of PERA/Ei and I/LnJ inbred strains of mice. METHODS: Mice of both sexes were examined for gallstone weight and evaluated according to a scoring system for the physical chemistry of cholelithiasis during feeding of a lithogenic diet. Intercross offspring were genotyped, and linkage analysis was performed by interval mapping. Differences in messenger RNA expression of positional candidate genes were determined using reverse-transcription and real-time polymerase chain reaction. RESULTS: We identified significant loci associated with gallstone weight on chromosomes 10 and 4, named Lith7 and Lith8, respectively (both susceptibility alleles conferred by strain I/LnJ). Positional candidate genes with higher expression in I/LnJ mice are Fxr (official symbol, Nr1h4), encoding the nuclear bile salt receptor, on chromosome 10 and Shp1 (official symbol, Nr0b2), encoding the small heterodimer partner 1, on chromosome 4. A significant locus associated with gallstone score on chromosome 17, named Lith9 (susceptibility allele conferred by strain PERA/Ei), colocalizes with the genes Abcg5 and Abcg8 that encode the canalicular cholesterol transporter. Higher hepatic messenger RNA expression of Abcg5 and Abcg8 in strain PERA/Ei correlates positively with higher biliary cholesterol levels. CONCLUSIONS: Our findings suggest a primary role of the nuclear bile salt receptor FXR and the canalicular cholesterol transporter ABCG5/ABCG8 in the genetic susceptibility and pathogenesis of cholesterol cholelithiasis in these strains of inbred mice.

• New quantitative trait loci that contribute to cholesterol gallstone formation detected in an intercross of CAST/Ei and 129S1/SvImJ inbred mice.

  Authors: Malcolm A Lyons, Henning Wittenburg, Renhua Li, Kenneth A Walsh, Monika R Leonard, Gary A Churchill, Martin C Carey, Beverly Paigen

  Physiological genomics. 09/2003; 14(3):225-39.

  Cholesterol gallstone formation is a response to interactions between multiple genes and environmental stimuli. To determine the subset of cholesterol gallstone susceptibility (Lith) genes possessedCholesterol gallstone formation is a response to interactions between multiple genes and environmental stimuli. To determine the subset of cholesterol gallstone susceptibility (Lith) genes possessed by strains CAST/Ei (susceptible) and 129S1/SvImJ (resistant), we conducted quantitative trait locus (QTL) analyses of an intercross between these strains. Parental strains and F(1) mice of both genders were evaluated for gallstone formation after consumption of a lithogenic diet for 8 wk. Gallstone susceptibility of strain CAST was predominantly due to cholesterol hypersecretion. Male intercross offspring were genotyped and phenotyped for cholesterol gallstone formation after consumption of the lithogenic diet for 10 wk. Linkage analysis was performed using PSEUDOMARKER software. One significant, new QTL was detected and named Lith13 [chromosome (Chr) 5, 30 cM]. Statistical analyses and QTL fine mapping suggest this QTL may comprise two closely linked loci. We confirmed the presence of Lith6 (Chr 6). Suggestive QTL were detected on Chrs 1, 2, 5, 14, and 16. The QTL on Chrs 2 and 16 confirmed previously identified, suggestive QTL. Therefore, they were named Lith12 (101 cM) and Lith14 (42 cM), respectively. We identified candidate genes based on known function and location and performed mRNA expression analyses using both parental strains and intercross progeny for preliminary evaluation of their contributions to gallstone formation. Cebpb (Lith12), Pparg (Lith6), and Slc21a1 (Lith6) displayed expression differences. Our work continues to demonstrate the genetic complexity and to elucidate the pathophysiology of cholesterol gallstone formation. It should facilitate the development of new approaches for treating this common human disorder.