Hartmut Schmidt

Universitätsklinikum Münster, Muenster, North Rhine-Westphalia, Germany

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Publications (25)223.62 Total impact

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    ABSTRACT: Chronic pancreatitis is an inflammatory disorder of the pancreas. We analyzed CPA1, encoding carboxypeptidase A1, in subjects with nonalcoholic chronic pancreatitis (cases) and controls in a German discovery set and three replication sets. Functionally impaired variants were present in 29/944 (3.1%) German cases and 5/3,938 (0.1%) controls (odds ratio (OR) = 24.9, P = 1.5 × 10(-16)). The association was strongest in subjects aged ≤10 years (9.7%; OR = 84.0, P = 4.1 × 10(-24)). In the replication sets, defective CPA1 variants were present in 8/600 (1.3%) cases and 9/2,432 (0.4%) controls from Europe (P = 0.01), 5/230 (2.2%) cases and 0/264 controls from India (P = 0.02) and 5/247 (2.0%) cases and 0/341 controls from Japan (P = 0.013). The mechanism by which CPA1 variants confer increased pancreatitis risk may involve misfolding-induced endoplasmic reticulum stress rather than elevated trypsin activity, as is seen with other genetic risk factors for this disease.
    Nature Genetics 08/2013; · 35.21 Impact Factor
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    ABSTRACT: In Egypt, Wilson disease seems to be under diagnosed and clinical data on large cohorts are limited. The aim of this study is to highlight the clinical, laboratory and genetic characteristics of this disease in our pediatric population as well as to report our experience with both treatment options and outcome. The study included 77 patients from 50 unrelated families (62 were followed up for a mean period of 58.9 ± 6.4 months and 27 were asymptomatic siblings). Data were collected retrospectively by record analysis and patient interviews. Diagnosis was confirmed by sequencing of the ATP7B gene in 64 patients. Our patients had unique characteristics compared to other populations. They had a younger age of onset (median: 10 years), higher prevalence of Kayser-Fleischer rings (97.6% in the symptomatic patients), low ceruloplasmin (93.5%), high rate of parental consanguinity (78.9%) as well as a more severe course. 71.42% of those on long term D-penicillamine improved or were stable during the follow up with severe side effects occurring in only 11.5%. Preemptive treatment with zinc monotherapy was an effective non-toxic alternative to D-penicillamine. Homozygous mutations were found in 85.7%, yet limited by the large number of mutations detected, it was difficult to find genotype-phenotype correlations. Missense mutations were the most common while protein-truncating mutations resulted in a more severe course with higher incidence of acute liver failure and neurological symptoms. Egyptian children with Wilson disease present with early Kayser-Fleischer rings and early onset of liver and neurological disease. The mutational spectrum identified differs from that observed in other countries. The high rate of homozygous mutations (reflecting the high rate of consanguinity) may potentially offer further insights on genotype-phenotype correlation.
    BMC Pediatrics 06/2011; 11:56. · 1.98 Impact Factor
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    ABSTRACT: Premature activation of pancreatic digestive enzymes is considered as a major factor in the pathogenesis of pancreatitis. Genetic alterations of different pancreatic zymogens or their inhibitors have been associated with chronic pancreatitis (CP). We sequenced all 12 GP2 exons in 380 German CP patients and in 182 German control subjects. In addition, we analyzed exon 3 of GP2 in 803 further CP patients and 1780 controls originating from Germany, the Netherlands, and India by targeted DNA sequencing. We detected 12 nonsynonymous and 6 synonymous exonic variants. All nonsynonymous changes with exception of c.220C>T (p.R74X) and c.502_503delG (p.G168fsX174) in exon 3 and c.541C>T (p.R181X) in exon 4 were missense mutations and predominantly located in exon 3. All nonsynonymous variants were found in single cases only, with exception of 2 alterations, c.355A>G (p.M119V) and c.409G>A (p. A137T), both located in exon 3. To elucidate the role of these 2 exon 3 variants, we investigated additional patients and controls. The frequency of these variants was similar between patients and controls regardless of ethnic background or cause of CP. Our data suggest that GP2 alterations do not alter the risk for the development of CP.
    Pancreas 11/2009; 39(2):188-92. · 2.95 Impact Factor
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    ABSTRACT: Apolipoprotein AI-derived (AApoAI) amyloidosis may present either as a non-hereditary form with wild-type protein deposits in atherosclerotic plaques or as a hereditary form due to germline mutations in the APOA1 gene. Currently, more than 50 apoAI variants are known, and 13 are associated with amyloidosis. We describe six patients with AApoAI amyloidosis due to APOA1 germline mutations that affect the larynx, small intestine, large intestine, heart, liver, kidney, uterus, ovary, or pelvic lymph nodes. In each patient, the amyloid showed a characteristic apple green birefringence when viewed under polarized light after Congo red staining and was immunoreactive with antibodies against apoAI. Sequence analyses revealed one known (p.Leu75Pro) and three novel APOA1 mutations that included gene variations leading to two different frameshifts (p.Asn74fs and p.Ala154fs) and one amino acid exchange (p.Leu170Pro). These three novel mutations extend our knowledge about both the location of the mutations and the organ distribution in hereditary AApoAI amyloidosis. Thirteen of the now sixteen amyloidogenic mutations are localized in two hot-spot regions that span residues 50 to 93 and 170 to 178. The organ distribution and clinical presentation of AApoAI amyloidosis seems to depend on the position of the mutation. Patients with alterations in codons 1 to 75 mostly develop hepatic and renal amyloidosis, while carriers of mutations in residues 173 to 178 mainly suffer from cardiac, laryngeal, and cutaneous amyloidosis.
    The Journal of molecular diagnostics: JMD 04/2009; 11(3):257-62. · 3.48 Impact Factor
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    ABSTRACT: Transthyretin-derived amyloidosis (ATTR) amyloidosis is the third most prevalent amyloid type in surgical pathology and may occur as a hereditary disease with germline mutations in the TTR gene or as senile systemic amyloidosis (SSA) without mutations. Distinction between hereditary ATTR amyloidosis and SSA is of central importance, as the former necessitates genetic counseling and can be treated by liver transplantation. However, little is known about the prevalence of hereditary ATTR amyloidosis in surgical pathology specimens. We have examined the distribution of hereditary ATTR amyloidosis and SSA in a consecutive series of surgical pathology specimens with histologically and immunohistochemically confirmed ATTR amyloid. Thirty-three consecutive patients were retrieved from the Amyloid Registry of the Charité University Hospital. Genomic DNA was extracted from formalin-fixed and paraffin-embedded tissue or patient blood and examined by DNA sequencing. ATTR amyloid was found in the gastrointestinal tract, endomyocardium, peripheral nerve, carpal tunnel ligament, synovia, breast, and testicle. Amyloid fibrils were present as interstitial and vascular deposits, as evidenced by Congo red staining. TTR gene mutations were detected in 12 of 30 patients, with p.Val30Met being the most prevalent (5 patients). Furthermore, 2 novel mutations (p.Asp39Val and p.Glu54Asp) were found. In patients carrying a mutation, ATTR amyloid was found in the gastrointestinal tract, myocardium, nerve, and testicles. To conclude, the hereditary form of ATTR amyloid seems to be more common in elderly patients than previously thought. It is, therefore, important to genetically test every patient when diagnosing ATTR amyloidosis.
    The American journal of surgical pathology 10/2008; 33(1):58-65. · 4.06 Impact Factor
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    ABSTRACT: Plasma protein fibrinogen variants cause fibrinogen A alpha-chain (AFib) amyloidosis, which presents with hypertension, proteinuria, and azotemia. Six AFib mutations have been reported thus far. We identified three patients who presented with marked proteinuria and serum creatinine elevations. Their kidney biopsies revealed destruction of the glomerular architecture by amyloid deposits with typical, apple-green birefringence in polarized light after Congo red staining. We found immunoreactivity against fibrinogen, which is typical for this type of amyloidosis. We sequenced the FGA exon 5 and demonstrated heterozygosity for the p.Glu526Val mutation in all three cases. This amino acid substitution is the most common fibrinogen A alpha-chain variant causing AFib amyloidosis. The mutation has been reported in individuals of European and American descent but not yet in German patients. AFib amyloidosis should therefore be considered an important differential diagnosis in German patients with renal amyloidosis. In the cases described here, the use of antibodies directed against fibrinogen, followed by direct gene sequencing, revealed the underlying cause.
    Archiv für Pathologische Anatomie und Physiologie und für Klinische Medicin 08/2008; 453(1):25-31. · 2.68 Impact Factor
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    ABSTRACT: The aim of this work was to study the mutations within ATP7B in Egyptian children with Wilson disease and to evaluate any potential correlation between genotype and phenotype in this cohort. The study consisted of 48 children with Wilson disease from 32 independent families. The 21 exons of the ATP7B gene were amplified in a thermal cycler. Direct sequencing of the amplified polymerase chain reaction (PCR) products was performed by cycle sequencing using fluorescent dye terminators in an automatic ABI sequencer. Thirty-one different mutations in 96 chromosomes were detected (19 missense, three nonsense, seven frameshift deletions, and two splice-site mutations). Of these, 12 mutations have not been previously reported. The p.N1270S, p.C703Y, IVS18-2A > G, p.R1319X, c.2304-2305insC, and p.H1069Q were present in 7.8%, 6.2%, 6.2%, 6.2%, 4.7%, and 4.7%, respectively, of studied chromosomes in independent families. One patient was homozygous for both p.N1270S and p.T1434M mutations. Frameshift and nonsense mutations were found in 50% of patients with disease onset < or =8 years compared with only 26% in patients with onset >8 years. Despite mutation heterogeneity in Egyptian children, genotype-phenotype correlation analysis seems to be promising in this population, as many patients carry homozygous mutations, a situation that mandates a larger-scale population screening to identify the carrier rate in this community.
    Journal of Human Genetics 05/2008; 53(8):681-7. · 2.37 Impact Factor
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    ABSTRACT: Chronic pancreatitis is a persistent inflammatory disease of the pancreas, in which the digestive protease trypsin has a fundamental pathogenetic role. Here we have analyzed the gene encoding the trypsin-degrading enzyme chymotrypsin C (CTRC) in German subjects with idiopathic or hereditary chronic pancreatitis. Two alterations in this gene, p.R254W and p.K247_R254del, were significantly overrepresented in the pancreatitis group, being present in 30 of 901 (3.3%) affected individuals but only 21 of 2,804 (0.7%) controls (odds ratio (OR) = 4.6; confidence interval (CI) = 2.6-8.0; P = 1.3 x 10(-7)). A replication study identified these two variants in 10 of 348 (2.9%) individuals with alcoholic chronic pancreatitis but only 3 of 432 (0.7%) subjects with alcoholic liver disease (OR = 4.2; CI = 1.2-15.5; P = 0.02). CTRC variants were also found in 10 of 71 (14.1%) Indian subjects with tropical pancreatitis but only 1 of 84 (1.2%) healthy controls (OR = 13.6; CI = 1.7-109.2; P = 0.0028). Functional analysis of the CTRC variants showed impaired activity and/or reduced secretion. The results indicate that loss-of-function alterations in CTRC predispose to pancreatitis by diminishing its protective trypsin-degrading activity.
    Nature Genetics 02/2008; 40(1):78-82. · 35.21 Impact Factor
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    ABSTRACT: Wilson's disease (WD) is a rare inborn metabolic error characterized by deficient biliary copper excretion secondary to ATP7B gene mutations. Neurological presentations are variable in respect to both pattern and age of onset; commonly a movement disorder presents in the second or third decade. The aim of this study was to ascertain genotype correlations with distinct neurological manifestations in 41 WD patients in a Brazilian center for WD. A total of 23 distinct mutations were detected, and the frameshift 3402delC had the highest allelic frequency (31.7%). An association between 3402delC and dysphagia was detected (p=0.01) but the limited number of patients is insufficient to allow one to draw conclusions. Both clinical studies analyzing larger cohorts and basic research on ATP7B protein function could potentially shed more light on our understanding of WD.
    Parkinsonism & Related Disorders 02/2008; 14(3):246-9. · 3.27 Impact Factor
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    ABSTRACT: Keratin 8 (KRT8) is one of the major intermediate filament proteins expressed in single-layered epithelia of the gastrointestinal tract. Transgenic mice over-expressing human KRT8 display pancreatic mononuclear infiltration, interstitial fibrosis and dysplasia of acinar cells resulting in exocrine pancreatic insufficiency. These experimental data are in accordance with a recent report describing an association between KRT8 variations and chronic pancreatitis. This prompted us to investigate KRT8 polymorphisms in patients with pancreatic disorders. The KRT8 Y54H and G62C polymorphisms were assessed in a cohort of patients with acute and chronic pancreatitis of various aetiologies or pancreatic cancer originating from Austria (n=16), the Czech Republic (n=90), Germany (n=1698), Great Britain (n=36), India (n=60), Italy (n=143), the Netherlands (n=128), Romania (n=3), Spain (n=133), and Switzerland (n=129). We also studied 4,234 control subjects from these countries and 1,492 control subjects originating from Benin, Cameroon, Ethiopia, Ecuador, and Turkey. Polymorphisms were analysed by melting curve analysis with fluorescence resonance energy transfer probes. The frequency of G62C did not differ between patients with acute or chronic pancreatitis, pancreatic adenocarcinoma and control individuals. The frequency of G62C varied in European populations from 0.4 to 3.8%, showing a northwest to southeast decline. The Y54H alteration was not detected in any of the 2,436 patients. Only 3/4,580 (0.07%) European, Turkish and Indian control subjects were heterozygous for Y54H in contrast to 34/951 (3.6%) control subjects of African descent. Our data suggest that the KRT8 alterations, Y54H and G62C, do not predispose patients to the development of pancreatitis or pancreatic cancer.
    Journal of Molecular Medicine 11/2006; 84(12):1015-1022. · 4.77 Impact Factor
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    ABSTRACT: Chronic pancreatitis is a common inflammatory disease of the pancreas. Mutations in the genes encoding cationic trypsinogen (PRSS1) and the pancreatic secretory trypsin inhibitor (SPINK1) are associated with chronic pancreatitis. Because increased proteolytic activity owing to mutated PRSS1 enhances the risk for chronic pancreatitis, mutations in the gene encoding anionic trypsinogen (PRSS2) may also predispose to disease. Here we analyzed PRSS2 in individuals with chronic pancreatitis and controls and found, to our surprise, that a variant of codon 191 (G191R) is overrepresented in control subjects: G191R was present in 220/6,459 (3.4%) controls but in only 32/2,466 (1.3%) affected individuals (odds ratio 0.37; P = 1.1 x 10(-8)). Upon activation by enterokinase or trypsin, purified recombinant G191R protein showed a complete loss of trypsin activity owing to the introduction of a new tryptic cleavage site that renders the enzyme hypersensitive to autocatalytic proteolysis. In conclusion, the G191R variant of PRSS2 mitigates intrapancreatic trypsin activity and thereby protects against chronic pancreatitis.
    Nature Genetics 07/2006; 38(6):668-73. · 35.21 Impact Factor
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    Diabetes Care 03/2006; 29(2):464-6. · 7.74 Impact Factor
  • Journal of Neurology 06/2005; 252(5):621-3. · 3.58 Impact Factor
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    ABSTRACT: Copper overload due to a defect in the ATPase 7B mediated copper excretion within hepatocytes produces the phenotype of Wilson disease. The overload of hepatocytes with copper results in necrotic liver cells and is accompanied by a high concentration of blood copper levels. That occurs to be the reason for increasing neurological copper concentration. Although copper is linked to oxidation, there are no data on the direct copper related effects in human brain cells. To test the copper induced changes in protein oxidation in human astrocyte like cells. We used U87 cells as model for human astrocytes. Cells were treated with increasing concentrations of copper(II)-chloride in Dulbeccos minimal essential medium. Subsequently, at different time points we investigated: cellular growth, cellular survival under copper treatment, the concentration of oxidized tryptophane in GADPH in vitro as well as the carbonyl concentration and the concentration of oxidized proteins in vivo in U87 glial cells. The viability of cells decreased with both increasing copper concentration and duration of treatment. The concentration of oxidized proteins was directly correlated to the increase of copper concentration and duration of exposure. These observations demonstrate the similarities between copper treatment and treatment with other commonly used oxidants, including hydrogen peroxide. Furthermore, the vulnerability of astrocytes towards copper exposure could be demonstrated. Therefore, these data give further insights into understanding of copper metabolism, which in turn is important to reveal the exact pathological mechanism in copper related diseases such as Wilson disease.
    BioFactors 02/2005; 24(1-4):255-61. · 3.09 Impact Factor
  • Gastrointestinal Endoscopy - GASTROINTEST ENDOSCOP. 01/2005; 61(5).
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    ABSTRACT: To analyse the impact of NOD2/CARD15 mutations on the clinical course of Crohn's disease patients from an eastern European country (Hungary). We investigated the prevalence of the three common NOD2/CARD15 mutations (Arg702Trp, Gly908Arg, 1007finsC) in 148 patients with Crohn's disease, 128 patients with ulcerative colitis and 208 controls recruited from the University of Szeged, Hungary. In patients with Crohn's disease, the prevalence of NOD2/CARD15 mutations was correlated to the demographical and clinical parameters. In total, 32.4% of Crohn's disease patients carried at least one mutant allele within NOD2/CARD15 compared to 13.2% of patients with ulcerative colitis (P = 0.0002) and to 11.5% of controls (P<0.0001). In Crohn's disease patients, the allele frequencies for Arg702Trp, Gly908Arg and 1007finsC were 7.1%, 3.0% and 10.8% respectively. Interestingly, only the 1007finsC mutation was associated with a distinct clinical phenotype. The patients positive for the 1007finsC mutation suffered more frequently from stenotic disease behaviour (P = 0.008). Furthermore, 51.9% of patients positive for the 1007finsC mutation underwent a surgical resection within the ileum compared to only 17.4% of patients without the 1007finsC mutation (P = 0.001). With respect to the other two mutations (Arg702Trp and Gly908Arg), no associations were found with all investigated clinical parameters. NOD2/CARD15 mutations are frequently found in Crohn's disease patients from Hungary. The 1007finsC mutation is associated with stenotic disease behaviour and frequent ileal resections.
    World Journal of Gastroenterology 01/2005; 11(3):407-11. · 2.55 Impact Factor
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    ABSTRACT: Familial hypercholesterolemia (FH) is a clinical definition for a remarkable increase of cholesterol serum concentration, presence of xanthomas, and an autosomal dominant trait of either increased serum cholesterol or premature coronary artery disease (CAD). The identification of the low-density lipoprotein (LDL)-receptor (LDLR) as the underlying cause and its genetic characterization in FH patients revealed more insights in the trafficking of LDL, which primarily transports cholesterol to hepatic and peripheral cells. Mutations within LDLR result in hypercholesterolemia and, subsequently, cholesterol deposition in humans to a variable degree. This confirms the pathogenetic role of LDLR and also highlights the existence of additional factors in determining the phenotype. Autosomal dominant FH is caused by LDLR deficiency and defective apolipoprotein B-100 (APOB), respectively. Heterozygosity of the LDLR is relatively common (1:500). Clinical diagnosis is highly important and genetic diagnosis may be helpful, since treatment is usually effective for this otherwise fatal disease. Very recently, mutations in PCSK9 have been also shown to cause autosomal dominant hypercholesterolemia. For autosomal recessive hypercholesterolemia, mutations within the so-called ARH gene encoding a cellular adaptor protein required for LDL transport have been identified. These insights emphasize the crucial importance of LDL metabolism intra- and extracellularly in determining LDL-cholesterol serum concentration. Herein, we focus on the published European LDLR mutation data that reflect its heterogeneity and phenotypic penetrance.
    Human Mutation 01/2005; 24(6):443-59. · 5.21 Impact Factor
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    ABSTRACT: To evaluate genotyping for two DNA variants (c.1993+327C>T and c.1438+117G>A), recently found to be associated with adult-type hypolactasia, in the diagnosis of lactose intolerance. In total, 166 consecutive patients with gastrointestinal symptoms mimicking hypolactasia admitted to the clinic between March 2002 and December 2002 were included. Genotyping for the two DNA variants (c.1993+327C>T and c.1438+117G>A) and standard H2 breath test was performed. Among 116 patients with positive H2 breath test, the c.1993+327C variant was detectable in 106 (91.4%) patients. Among 50 patients with negative H2 breath test, the c.1993+327C variant was seen in 2 patients. Sensitivity, specificity, positive and negative predictive values for the c.1993+327C variant were 91.4, 96.0, 98.1 and 82.8%, respectively. Genotyping for the c.1438+117G variant did not bring any additional information. Among 4 of the 10 patients with positive H2 breath test but negative for the c.1993+327C and the c.1438+117G variant,further evaluation revealed other diseases known to cause secondary hypolactasia such as celiac disease and short bowel syndrome. In symptomatic patients, genotyping for the DNA variant c.1993+327C is a reliable test for adult-type hypolactasia with high sensitivity and specificity and thus provides a new tool in the diagnostic workup of hypolactasia.
    Digestion 01/2005; 71(4):245-50. · 1.94 Impact Factor
  • Journal of Bone and Mineral Research 11/2004; 19(10):1746; author reply 1747. · 6.13 Impact Factor
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    ABSTRACT: We used the denaturing gradient gel electrophoresis (DGGE) method to define mutations in the promoter region, the 18 exons, and their flanking intronic sequences of the low-density lipoprotein (LDL) receptor gene LDLR, causing familial hypercholesterolemia (FH) phenotype in 100 German and in 100 Greek hypercholesterolemic individuals. In addition, we tested all patients for the presence of mutations in codons 3456-3553 of the gene encoding apolipoprotein B-100 (APOB). Twenty-six aberrant DGGE patterns were identified and subsequently directly sequenced. In LDLR, two novel missense mutations (c.1957G>T/p.V653F, c.647 G>A/p.C216Y) and one novel homozygous base substitution c.1-156 C>T in the repeat 2 of the promoter region were identified among German FH patients; one novel splice site c.1060+10C>G was identified among Greek FH patients. One of the German FH patients was a carrier for the mutations c.1171G>A/p.A391T and p.V653F, and two of the Greek FH patients were compound heterozygotes for the mutations c.1150C>T/p.Q384X and c.1158C>G/p.D386E. Two German FH patients carried the mutation p.R3500Q within APOB. Comparing the mutations within the LDLR gene of the two European FH populations, the German population seems to be more heterogeneous than the Greek cohort. Further studies in progress are trying to elucidate the responsiveness to drug therapy in association with LDLR genotype and the nutritional habits of the two FH populations.
    Human Mutation 03/2004; 23(3):285-6. · 5.21 Impact Factor

Publication Stats

452 Citations
223.62 Total Impact Points

Institutions

  • 2011
    • Universitätsklinikum Münster
      Muenster, North Rhine-Westphalia, Germany
  • 2005–2009
    • Charité Universitätsmedizin Berlin
      • Medical Department, Division of Hepatology and Gastroenterology
      Berlín, Berlin, Germany
  • 2008
    • University of Münster
      Muenster, North Rhine-Westphalia, Germany
    • Ain Shams University
      • Department of Pediatrics
      Cairo, Muhafazat al Qahirah, Egypt
  • 2002
    • University of Rostock
      Rostock, Mecklenburg-Vorpommern, Germany