Heidi Rossmann

Johannes Gutenberg-Universität Mainz, Mayence, Rheinland-Pfalz, Germany

Are you Heidi Rossmann?

Claim your profile

Publications (65)374.13 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Context: Mutations in the four subunits of succinate dehydrogenase (SDH) are the cause for the hereditary paraganglioma (PGL) syndromes type 1-4 and are associated with multiple and recurrent pheochromocytomas (Pheo) and PGLs. SDHC mutations most frequently result in benign, non-functional head-and neck PGLs (HNPGLs). The malignant potential of SDHC mutations remains unclear to date. Objectives: We report a patient with malignant PGL carrying a SDHC mutation and compare her case with two others of the same genotype but presenting with classic benign HNPGLs. Loss of heterozygosity (LOH) was demonstrated in the malignant PGL tissue. Design: In three unrelated patients referred for routine genetic testing SDHB, SDHC, and SDHD genes were sequenced and gross deletions were excluded by MLPA (MRC Holland). LOH was determined by pyrosequencing-based allele quantification and SDHB immunohistochemistry. Results: In a patient with a non-functioning thoracic PGL metastatic to the bone, the lungs and mediastinal lymph nodes we detected the SDHC mutation c.397C>T predicting a truncated protein due to a premature stop codon (p.Arg133*). We demonstrated LOH and loss of SDHB protein expression in the malignant tumor tissue. The two other patients also carried c.397C>T, p.Arg133*; they differed from each other with respect to their tumor characteristics but both showed benign HNPGLs. Conclusions We describe the first case of a malignant PGL with distant metastases caused by a SDHC germline mutation. The present case shows that SDHC germline mutations can have highly variable phenotypes and may cause malignant PGL even though malignancy is probably rare.
    The Journal of Clinical Endocrinology and Metabolism 01/2014; · 6.31 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE: Knowledge of the genetic backgrounds of hereditary syndromes, which are increasingly being characterized, enables genetic screening of family members of affected patients. Upon detection of a mutation, genetic counselling and clinical screening including imaging modalities and biochemical analyses are commonly performed. METHODS: Unaffected, mutation-positive relatives of index patients with hereditary paraganglioma syndromes were offered PET imaging with [(18)F]fluorodihydroxyphenylalanine and the incidence of pathological findings was retrospectively analysed in relation to mutations of the succinate dehydrogenase enzyme complex. PET only or PET/CT was performed in 21 individuals from eight families with SDHD, one family with SDHC and two families with SDHB mutations. Screening was offered every 2 to 5 years. RESULTS: Of the 21 individuals, 14 showed paraganglioma during screening. In particular, in only 2 of 15 patients with a SDHD mutation were the findings completely unremarkable on PET screening. However, false-negative lesions for abdominal manifestations in two SDHD-positive patients were detected. CONCLUSION: FDOPA PET is a sensitive imaging modality which should be offered to patients with a detected SDHx (SDHD) mutation, preferably using a hybrid technique.
    European Journal of Nuclear Medicine 02/2013; · 4.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Clinical and experimental evidence suggests a protective role for the antioxidant enzyme glutathione peroxidase-1 (GPx-1) in the atherogenic process. GPx-1 deficiency accelerates atherosclerosis and increases lesion cellularity in ApoE(-/-) mice. However, the distribution of GPx-1 within the atherosclerotic lesion as well as the mechanisms leading to increased macrophage numbers in lesions is still unknown. Accordingly, the aims of the present study were (1) to analyze which cells express GPx-1 within atherosclerotic lesions and (2) to determine whether a lack of GPx-1 affects macrophage foam cell formation and cellular proliferation. Both in situ-hybridization and immunohistochemistry of lesions of the aortic sinus of ApoE(-/-) mice after 12 weeks on a Western type diet revealed that both macrophages and - even though to a less extent - smooth muscle cells contribute to GPx-1 expression within atherosclerotic lesions. In isolated mouse peritoneal macrophages differentiated for 3 days with macrophage-colony-stimulating factor (MCSF), GPx-1 deficiency increased oxidized low density-lipoprotein (oxLDL) induced foam cell formation and led to increased proliferative activity of peritoneal macrophages. The MCSF- and oxLDL-induced proliferation of peritoneal macrophages from GPx-1(-/-)ApoE(-/-) mice was mediated by the p44/42 MAPK (p44/42 mitogen-activated protein kinase), namely ERK1/2 (extracellular-signal regulated kinase 1/2), signaling pathway as demonstrated by ERK1/2 signaling pathways inhibitors, Western blots on cell lysates with primary antibodies against total and phosphorylated ERK1/2, MEK1/2 (mitogen-activated protein kinase kinase 1/2), p90RSK (p90 ribosomal s6 kinase), p38 MAPK and SAPK/JNK (stress-activated protein kinase/c-Jun N-terminal kinase), and immunohistochemistry of mice atherosclerotic lesions with antibodies against phosphorylated ERK1/2, MEK1/2 and p90RSK. Representative effects of GPx-1 deficiency on both macrophage proliferation and MAPK phosphorylation could be abolished by the GPx mimic ebselen. The present study demonstrates that GPx-1 deficiency has a significant impact on macrophage foam cell formation and proliferation via the p44/42 MAPK (ERK1/2) pathway encouraging further studies on new therapeutic strategies against atherosclerosis.
    PLoS ONE 01/2013; 8(8):e72063. · 3.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: Dyslipidemia in Gaucher disease includes reduced total, low-density lipoprotein (LDL)-, and high-density lipoprotein (HDL)-cholesterol (C). No prospective analysis of lipid profile changes in treatment-naïve patients under enzyme replacement therapy (ERT) is available. METHODS: We analyzed lipid profile changes during ERT in a prospective controlled manner. Twelve treatment-naïve patients, Gaucher disease type 1 (GD1), 29.5 ± 12.9 years, 4M/8F. Diagnosis was made by enzymatic measurement and mutational analysis. Total-, LDL-, and HDL-C, triglycerides (TG), and LDL subfractions were assessed before the start of ERT with imiglucerase and biannually for 3 years. Patients were matched with healthy controls before and after 3 years of ERT. RESULTS: At baseline, we found severely reduced HDL-C concentrations (23.6 ± 5.4 mg/dl) and enhanced LDL/HDL ratios (3.1 ± 0.7). HDL-C increased after 6 months (29.2 ± 5.7, p = 0.023), LDL/HDL ratio decreased after 30 months (2.5 ± 0.5, p = 0.039). TG, even not consistently enhanced at baseline (128 ± 31.3 mg/dl), yet higher than in controls (p < 0.001), decreased after 18 months, being comparable with controls after 3 years of ERT. Small, dense LDL (mg/dl) increased continuously without significant difference to controls. After 3 years of ERT, only reduced HDL-C concentrations persisted as a potentially atherogenic alteration; however, mean concentrations markedly improved (42.9 ± 8.3 mg/dl, p < 0.001). Lipid parameters correlated with six markers of disease severity. CONCLUSIONS: This is the first prospective controlled study regarding lipid profile dynamics during ERT (glucocerebrosidase) in initially treatment-naïve GD1 patients. The most important changes were reduced HDL-C and enhanced LDL/HDL ratio. Their dynamics during ERT and correlations with markers of disease activity suggest that they can be considered markers of disease severity and follow-up in Gaucher patients under treatment.
    Journal of Inherited Metabolic Disease 09/2012; · 4.07 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Crohn's disease and ulcerative colitis, the two main types of inflammatory bowel disease (IBD), were reported to be associated with a variety of genetic polymorphisms. A subset of these polymorphisms was identified in both diseases and only three of them were found in primary sclerosing cholangitis (PSC). rs3197999 (Arg689Cys) located in the MST1 gene is one of the most convincingly replicated IBD/PSC-associated polymorphisms but its functional consequences have not been investigated, yet. We expressed both MST1 gene variants (Arg(689) (MSP(wt)) and Cys(689) (MSP(mut)) in a eukaryotic cell system and compared their stimulatory effects on macrophage-like THP-1 cells. Except for the rate of apoptosis that remained unchanged, MSP(mut) significantly increased the stimulatory effect of MSP (macrophage-stimulating protein) on chemotaxis and proliferation by THP-1 cells, indicating a gain of function associated with the Arg689Cys exchange. A broad set of evidence reported previously suggests that pro-inflammatory changes in macrophage function have a major role in the initiation of the inflammatory process in IBD and PSC. Therefore, the gain of function observed with rs3197999 in MST1 might provide a cellular mechanism for the consistent association of this polymorphism with an increased risk for IBD and PSC.
    Genes and immunity 01/2012; 13(4):321-7. · 4.22 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: One major expectation from the transcriptome in humans is to characterize the biological basis of associations identified by genome-wide association studies. So far, few cis expression quantitative trait loci (eQTLs) have been reliably related to disease susceptibility. Trans-regulating mechanisms may play a more prominent role in disease susceptibility. We analyzed 12,808 genes detected in at least 5% of circulating monocyte samples from a population-based sample of 1,490 European unrelated subjects. We applied a method of extraction of expression patterns-independent component analysis-to identify sets of co-regulated genes. These patterns were then related to 675,350 SNPs to identify major trans-acting regulators. We detected three genomic regions significantly associated with co-regulated gene modules. Association of these loci with multiple expression traits was replicated in Cardiogenics, an independent study in which expression profiles of monocytes were available in 758 subjects. The locus 12q13 (lead SNP rs11171739), previously identified as a type 1 diabetes locus, was associated with a pattern including two cis eQTLs, RPS26 and SUOX, and 5 trans eQTLs, one of which (MADCAM1) is a potential candidate for mediating T1D susceptibility. The locus 12q24 (lead SNP rs653178), which has demonstrated extensive disease pleiotropy, including type 1 diabetes, hypertension, and celiac disease, was associated to a pattern strongly correlating to blood pressure level. The strongest trans eQTL in this pattern was CRIP1, a known marker of cellular proliferation in cancer. The locus 12q15 (lead SNP rs11177644) was associated with a pattern driven by two cis eQTLs, LYZ and YEATS4, and including 34 trans eQTLs, several of them tumor-related genes. This study shows that a method exploiting the structure of co-expressions among genes can help identify genomic regions involved in trans regulation of sets of genes and can provide clues for understanding the mechanisms linking genome-wide association loci to disease.
    PLoS Genetics 12/2011; 7(12):e1002367. · 8.52 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Morbus Fabry is a hereditary metabolic disorder with low prevalence and late clinical manifestation. A defect in the α-galactosidase gene leads to lysosomal accumulation of the glycolipid globotriaosylceramide (Gb3). Gb3 may be used for monitoring of enzyme replacement therapy (ERT), but diagnostic sensitivity is limited. Recently, globotriaosylsphingosine (lysoGb3) was introduced as a promising new marker with significantly better sensitivity. For Fabry diagnosis, clinical studies and possible therapy monitoring, we established a fast and reliable LC-MS/MS assay for quantification of lysoGb3 in human plasma. Protein precipitation and glycolipid extraction from EDTA plasma was performed using acetone/methanol. Samples were analyzed by UPLC-MS/MS in MRM mode. In contrast to HPLC with fluorescence detection, the LC-MS/MS method requires no derivatization, less sample preparation and less instrument analysis time (<3 min). As internal standard (ISTD), a glycine derivative of lysoGb3 was synthesized, and the product was purified by HPLC. ISTD properties such as polarity (affecting extraction and elution), ionization and fragmentation pathway were almost identical compared to the analyte. The new LC-MS/MS assay for the Fabry marker lysoGb3 shows good performance and allowed for better discrimination between Fabry patients and controls than Gb3.
    Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 11/2011; 883-884:128-35. · 2.78 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Cerebral hypometabolism and abnormal levels of amyloid beta (Aβ), total (t-tau) and phosphorylated tau (ptau) proteins in cerebrospinal fluid (CSF) are established biomarkers of Alzheimer's disease (AD). We examined the agreement between these biomarkers in a single center study of patients with AD of severity extending over a wide range. Forty seven patients (MMSE 21.4 ± 3.6, range 13-28 points) with incipient and probable AD underwent positron emission tomography with [18F]-fluorodeoxyglucose (FDG-PET) and lumbar puncture for CSF assays of Aβ1-42, p-tau181, and t-tau. All findings were classified as either positive or negative for AD. Statistical analyses were performed for the whole sample (n=47) and for the subgroups stratified as mild (MMSE > 20 points, n=30) and moderate (MMSE < 21 points, n=17) AD. In the whole patient sample, the agreement with the FDG-PET finding was 77% (chance-corrected kappa [κ]=0.34, p=0.016) for t-tau, 68% (κ=0.10, n.s.) for p-tau181, and 68% (κ=0.04, n.s.) for Aβ1-42. No significant agreement was found in the mild AD subgroup, while there was a strong agreement for t-tau (94%, κ=0.77, p=0.001) and p-tau181 (88%, κ=0.60, p=0.014) in the moderate AD group. A significant agreement between the FDG-PET and CSF tau findings in patients with AD supports the view that both are markers of neurodegeneration. CSF tau proteins and FDG-PET might substitute each other as supportive diagnostic tools in patients with suspected moderate-to-severe Alzheimer's dementia, while this is not the case in subjects at an earlier disease stage.
    Current Alzheimer research 10/2011; 9(2):241-7. · 4.97 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Attention of the otorhinolaryngologist needs to be drawn to the versatile aspects of head and neck paragangliomas (PGLs). This study is a retrospective, nonrandomized clinical study of all 175 individuals with PGLs treated in our department between 1989 and 2010. A genetic analysis was performed on 86 patients. The 175 patients presented 224 head and neck PGLs as well as 2 thyroid papillary carcinomas. Genetic analysis resulted in 1 patient positive for a von Hippel-Lindau (VHL) gene mutation and 34 for succinate dehydrogenase (SDH) gene mutations (22 SDHD, 7 SDHC, and 5 SDHB), 12 of the latter carrying a novel mutation. Thirty-three patients (18.9%) had multiple PGLs and 11 patients (6.3%) had a malignant paraganglioma. SDH-mutation carriers had multiple tumors in 64.7% and malignant paragangliomas in 20.6%. Multifocal occurrence, potential malignancy, genetic aspects, possible coincidence of thyroid carcinoma, and hormone production have to be considered in patients with head and neck PGLs.
    Head & Neck 06/2011; 34(5):632-7. · 2.83 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: NASH (non-alcoholic steatohepatitis) is considered the hepatic manifestation of the metabolic syndrome (MS). We aimed to analyze lipid, carbohydrate, and iron metabolism in NASH. 37 patients with MS (17 M/20 F, 51+/-15 years), elevated transaminases; 25 patients had histologically proven NASH (NAS score≥5), 12 patients had toxic background (nonNASH). 37 age, sex, BMI-matched healthy controls. Lipid variables, LDL-subfractions, iron, ferritin, transferrin (T), transferrin saturation (TS), and hepcidin (H) were measured in patients/controls. Oral glucose tolerance tests were performed. NASH patients with steatosis gr. 2 and 3 (>33% hepatic fat) had higher sd-LDL (mg/dl) concentrations than patients with steatosis gr. 1 (<33%) (p=0.002), nonNASH patients (p=0.03) and controls (p=0.001). Sd absolute (mg/dl) correlated directly with the steatosis grade only in patients with NASH and steatosis >33% (p=0.04). NASH-patients showed higher insulin, C-peptide and IRI values than nonNASH patients (p=0.034; 0.032; 0.04). H was increased in patients versus controls (p<0.001). H correlated with ferritin in MS-patients (p=0.01), correlated directly with sd-LDL (mg/dl) (p=0.017) and IRI (p<0.001) and indirectly with HDL (p=0.05) in NASH. No associations between hepatic inflammation/iron content on liver biopsy and variables of lipid metabolism were found but hepcidin correlated with hepatic inflammation in all patients and with NAS scores in NASH. NASH-patients show insulin resistance and increased sd-LDL subfractions, suggesting an atherogenic profile. The correlation of H with sd-LDL and IRI, without relation to hepatic iron content suggests a putative link between inflammation, carbohydrate and lipid metabolism in NASH.
    European Journal of Internal Medicine 06/2011; 22(3):305-10. · 2.30 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: eQTL analyses are important to improve the understanding of genetic association results. We performed a genome-wide association and global gene expression study to identify functionally relevant variants affecting the risk of coronary artery disease (CAD). In a genome-wide association analysis of 2078 CAD cases and 2953 control subjects, we identified 950 single-nucleotide polymorphisms (SNPs) that were associated with CAD at P<10(-3). Subsequent in silico and wet-laboratory replication stages and a final meta-analysis of 21 428 CAD cases and 38 361 control subjects revealed a novel association signal at chromosome 10q23.31 within the LIPA (lysosomal acid lipase A) gene (P=3.7×10(-8); odds ratio, 1.1; 95% confidence interval, 1.07 to 1.14). The association of this locus with global gene expression was assessed by genome-wide expression analyses in the monocyte transcriptome of 1494 individuals. The results showed a strong association of this locus with expression of the LIPA transcript (P=1.3×10(-96)). An assessment of LIPA SNPs and transcript with cardiovascular phenotypes revealed an association of LIPA transcript levels with impaired endothelial function (P=4.4×10(-3)). The use of data on genetic variants and the addition of data on global monocytic gene expression led to the identification of the novel functional CAD susceptibility locus LIPA, located on chromosome 10q23.31. The respective eSNPs associated with CAD strongly affect LIPA gene expression level, which was related to endothelial dysfunction, a precursor of CAD.
    Circulation Cardiovascular Genetics 05/2011; 4(4):403-12. · 6.73 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Pheochromocytomas (PHEOs) and paragangliomas (PGLs) may be better detected by (18)F-fluorodihydroxyphenylalanine-positron emission tomography (FDOPA-PET) than (123)I-metaiodobenzyl-guanidine (123-I-MIBG) scintigraphy. The objective of the study was to correlate functional imaging results with immunohistochemical, molecular-genetic, and biochemical findings. Thirty consecutive patients with suspected PHEO/PGL presenting at a tertiary referral centre were investigated in a prospective study. Twenty-five patients had confirmed PHEO/PGL. Thirteen of 25 patients had a hereditary PHEO/PGL syndrome (two multiple endocrine neoplasia II, six succinate dehydrogenase complex, subunit D, two succinate dehydrogenase complex, subunit B, one von Hippel Lindau tumor suppressor protein, two Neurofibromatosis-1), and 12 of 25 were classified as sporadic. Five patients had hormonally inactive adrenal incidentalomas. In all patients computed tomography scan and/or magnetic resonance imaging as well as both 123-I-MIBG scintigraphy and FDOPA-PET were performed. Resected tumors were examined by immunohistochemistry for expression of the vesicular monoamine transporter (VMAT)-1 and -2 and other markers. A total of 64 lesions were found with both functional imaging modalities. FDOPA-PET detected 62 lesions, whereas only 34 lesions were detected by 123-I-MIBG scintigraphy. This resulted in an overall sensitivity and specificity for FDOPA-PET of 98 and 100% and for MIBG of 53 and 91%, respectively. Comparable sensitivities were found for adrenal and extraadrenal abdominal lesions (94 vs. 97%), whereas in thoracic/cervical lesions, the sensitivity for 123-I-MIBG scintigraphy (15%) was inferior to that of FDOPA-PET imaging (100%). Immunohistochemistry demonstrated a lack of VMAT-1 expression in all MIBG-negative tumors. Clinical predictors for MIBG negativity were a predominant norepinephrine/normetanephrine secretion, an age less than 45 yr, and a hereditary cause. FDOPA-PET is superior to 123-I-MIBG scintigraphy in patients with extraadrenal, predominantly noradrenaline-secreting, and hereditary types of PHEO/PGL. The lack of VMAT-1 expression predicts negativity for MIBG-scintigraphy.
    The Journal of Clinical Endocrinology and Metabolism 04/2010; 95(6):2800-10. · 6.31 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Variability of gene expression in human may link gene sequence variability and phenotypes; however, non-genetic variations, alone or in combination with genetics, may also influence expression traits and have a critical role in physiological and disease processes. To get better insight into the overall variability of gene expression, we assessed the transcriptome of circulating monocytes, a key cell involved in immunity-related diseases and atherosclerosis, in 1,490 unrelated individuals and investigated its association with >675,000 SNPs and 10 common cardiovascular risk factors. Out of 12,808 expressed genes, 2,745 expression quantitative trait loci were detected (P<5.78x10(-12)), most of them (90%) being cis-modulated. Extensive analyses showed that associations identified by genome-wide association studies of lipids, body mass index or blood pressure were rarely compatible with a mediation by monocyte expression level at the locus. At a study-wide level (P<3.9x10(-7)), 1,662 expression traits (13.0%) were significantly associated with at least one risk factor. Genome-wide interaction analyses suggested that genetic variability and risk factors mostly acted additively on gene expression. Because of the structure of correlation among expression traits, the variability of risk factors could be characterized by a limited set of independent gene expressions which may have biological and clinical relevance. For example expression traits associated with cigarette smoking were more strongly associated with carotid atherosclerosis than smoking itself. This study demonstrates that the monocyte transcriptome is a potent integrator of genetic and non-genetic influences of relevance for disease pathophysiology and risk assessment.
    PLoS ONE 01/2010; 5(5):e10693. · 3.53 Impact Factor
  • Atherosclerosis Supplements - ATHEROSCLER SUPPL. 01/2010; 11(2):99-99.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Classic 21-hydroxylase deficiency (21HD) presents some traits of the metabolic syndrome. To characterize discrete alterations of lipid and carbohydrate metabolism in children and young adults with classic 21HD, which could predict early atherogenesis. Twenty-seven Caucasian patients with classic 21HD (4-31 years); 27 sex-, age- and BMI-matched controls. Clinical parameters, hormonal status and genotype were assessed in all patients. Lipid parameters, including relative (%) and absolute (mg/dl) small-dense low-density lipoproteins subfractions (sd-LDL) were measured in patients and controls. Oral glucose tolerance tests were performed in both groups. sd-LDL (%) was significantly higher in patients than controls (39.7 +/- 5.9 vs. 35.5 +/- 5.7%; p = 0.008). The same applies for absolute sd-LDL (mg/dl) (42.6 +/- 11.9 vs. 36.4 +/- 7.5; p = 0.029). HDL-cholesterol was lower in patients (p = 0.032). Fasting glucose and insulin were significantly higher in patients. Similar differences were noticed for HOMA-IR (p = 0.001), IRI (p = 0.001) and HOMA-B (p = 0.002). IRI correlated directly and significantly with the total hydrocortisone dose and the duration of treatment. Fasting glucose correlated with absolute sd-LDL. No obvious differences were seen between clinical forms or genotype groups. Substitution therapy should be adapted particularly at young ages to prevent early atherogenesis and cardiovascular risk in later life.
    Hormone Research in Paediatrics 01/2010; 74(1):41-9. · 1.55 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Fabry disease is an X-chromosomally inherited lysosomal storage disorder leading to accumulation of glycosphingolipids, mainly globotriaosylceramide (ceramide-trihexoside, Gb3). Concentrations of Gb3 in plasma and urine have been used to diagnose Fabry disease and to monitor enzyme replacement therapy with recombinant alpha-galactosidase. Gb3 was purified from plasma or urine by combined liquid extraction/protein precipitation and solid-phase extraction, and was detected by flow-injection analysis electrospray mass spectrometry (MS) using multi-reaction-monitoring. Calibration was performed via standard addition using C17-Gb3 as internal standard. The most abundant isoforms were monitored for calculation of total Gb3. A MS-based assay for quantification of Gb3 in plasma and urine was established and validated. Intra- and inter-assay coefficient of variation (CV) of the method were <or=12%. However, at low concentrations the CV was 16%. The linear range covers roughly two orders of magnitude, down to 0.54 mg/L in plasma and 0.07 mg/L in urine. Careful adjustment of tuning parameters was necessary to obtain identical isoform intensities and quantitative results on different mass spectrometers. Gb3 concentrations in healthy controls were <4 mg/L in EDTA-plasma and <10 microg/mmol creatinine in urine. Significantly increased Gb3 concentrations were found in plasma and urine from male and female patients with Fabry disease. An improved MS protocol for Gb3 quantification has been developed, validated, and shown to be suitable for diagnosis and monitoring of Fabry patients.
    Clinical Chemistry and Laboratory Medicine 12/2009; 48(2):189-98. · 3.01 Impact Factor
  • Source
    Clinical Chemistry 06/2009; 55(5):1026-30; discussion 1030-1. · 7.15 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Reliable PCR amplification of DNA fragments is the prerequisite for most genetic assays. We investigated the impact of G-quadruplex- or i-motif-like sequences on the reliability of PCR-based genetic analyses. We found the sequence context of a common intronic polymorphism in the MEN1 gene (multiple endocrine neoplasia I) to be the cause of systematic genotyping errors by inducing preferential amplification of one allelic variant [allele dropout (ADO)]. Bioinformatic analyses and pyrosequencing-based allele quantification enabled the identification of the underlying DNA structures. We showed that G-quadruplex- or i-motif-like sequences can reproducibly cause ADO. In these cases, amplification efficiency strongly depends on the PCR enzyme and buffer conditions, the magnesium concentration in particular. In a randomly chosen subset of candidate single-nucleotide polymorphisms (SNPs) defined by properties deduced from 2 originally identified ADO cases, we confirmed preferential PCR amplification in up to 50% of the SNPs. We subsequently identified G-quadruplex and i-motifs harboring a SNP that alters the typical motif as the cause of this phenomenon, and a genomewide search based on the respective motifs predicted 0.5% of all SNPs listed by dbSNP and Online Mendelian Inheritance in Man to be potentially affected. Undetected, the described phenomenon produces systematic errors in genetic analyses that may lead to misdiagnoses in clinical settings. PCR products should be checked for G-quadruplex and i-motifs to avoid the formation of ADO-causing secondary structures. Truly affected assays can then be identified by a simple experimental procedure, which simultaneously provides the solution to the problem.
    Clinical Chemistry 05/2009; 55(7):1361-71. · 7.15 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Cystic fibrosis (CF) is a common autosomal recessive genetic disorder caused by a variety of sequence alterations in the CFTR gene [cystic fibrosis transmembrane conductance regulator (ATP-binding cassette sub-family C, member 7)]. Because the relative prevalence of mutations strongly depends on the ethnic background, first-level testing of CF as defined by recent consensus recommendations ought to be adaptable to the ethnicity of patients. We therefore developed and implemented a diagnostic approach to first-level testing for CF based on published mutation frequencies and Pyrosequencing (PSQ) technology that we complemented with standard procedures of mutation detection at the second level. The current test system of PSQ assays for 46 target CF mutations [including CFTRdele2,3 (21 kb) and 1342-6 (T)(n) (5T/7T/9T)] permits recombinations of single assays to optimize sensitivities for certain ethnicities. By easy expansion of the original mutation panel, the first-level test sensitivities with other ethnic groups would be increased, provided that the mutation frequencies are known. The test was validated with our local, ethnically mixed, but mainly German population (155 patients). The mutation-detection rate for the 92 patients whose CF was confirmed by the sweat test was 89.0% for the patients of German descent (73 of the 92 patients) and 73.7% for the patients of any other origin (19 of the 92 patients). Ethnicity-adapted testing panels for our foreign CF patients would increase the sensitivities for the respective groups by approximately 5%. PSQ-based genotyping is a reliable, convenient, highly flexible, and inexpensive alternative to conventional methods for first-level testing of CFTR, facilitating flexible adaptation of the analyzed mutation panel to any local ethnic group.
    Clinical Chemistry 05/2009; 55(6):1083-91. · 7.15 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Paragangliomas of the head and neck are rare, mostly benign tumors. Approximately 10% to 15% of paragangliomas are caused by mutations in the succinate dehydrogenase (SDH) genes B, C, or D. These are often multifocal as part of paraganglioma syndromes and hormone secreting, and malignant particularly associated with mutations in SDHB. A 29-year-old man was seen with recurrent paraganglioma. The patient's father reportedly suffered from bilateral carotid body tumors. Imaging studies showed metastases in both lungs and the liver. There was no increased hormone production by the tumor. Sequence analysis of the SDH genes revealed a novel C to T nonsense mutation in the first exon of the SDHD gene (R17X). A novel mutation in the SDHD gene associated with malignant paraganglioma is reported. This case underscores the relevance of family history and genetic analysis, thus permitting early detection of unaffected carriers. These have to be monitored clinically, biochemically and by imaging techniques.
    Head & Neck 08/2008; 30(7):964-9. · 2.83 Impact Factor

Publication Stats

1k Citations
374.13 Total Impact Points

Institutions

  • 2005–2012
    • Johannes Gutenberg-Universität Mainz
      Mayence, Rheinland-Pfalz, Germany
    • University of Münster
      • Institute of Physiology
      Münster, North Rhine-Westphalia, Germany
  • 2011
    • Universitätsmedizin der Johannes Gutenberg-Universität Mainz
      • Institute of Clinical Chemistry and Laboratory Medicine (Central Laboratory)
      Mainz, Rhineland-Palatinate, Germany
  • 1998–2005
    • University of Tuebingen
      • • Department of Internal Medicine
      • • Institute of Medical Psychology and Behavioral Neurobiology
      • • Eye Hospital
      Tübingen, Baden-Württemberg, Germany
    • Max Planck Institute of Biochemistry
      München, Bavaria, Germany
  • 2004
    • Hannover Medical School
      • Department of Gastroenterology, Hepatology and Endocrinology
      Hannover, Lower Saxony, Germany
  • 2003
    • Hochschule Hannover
      Hanover, Lower Saxony, Germany
  • 1999
    • Beth Israel Deaconess Medical Center
      Boston, Massachusetts, United States