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Featured researches published by Felix G. Riepe.


Hormone Research in Paediatrics | 2002

Consensus Statement on 21-Hydroxylase Deficiency from The European Society for Paediatric Endocrinology and The Lawson Wilkins Pediatric Endocrine Society

M. Vogeser; R. Zachoval; T.W. Felbinger; K. Jacob; G. Radetti; G. Bona; A. Corrias; M. Cappa; V. DeSanctis; S. Lauriola; C. Paganini; F. Rigon; Gian Luca Mainardi; Roberta Saleri; C. Tamanini; Mario Baratta; Gunter Simic-Schleicher; Felix G. Riepe; Nils Krone; Matthias Viemann; Carl-Joachim Partsch; Wolfgang G. Sippell; C. Castro; C. Trivin; J.-C. Souberbielle; M. Zerah; Raja Brauner; Shunichi Takahashi; Noboru Satozawa

1Writing Committee: Peter E. Clayton, Royal Manchester Children’s Hospital, Manchester, UK; Walter L. Miller*,University of California, San Francisco, Calif., USA; Sharon E. Oberfield, Columbia University, New York, N.Y., USA;E. Martin Ritzen, Karolinska Institute, Stockholm, Sweden; Wolfgang G. Sippell*, University Children’s Hospital,Kiel, Germany; Phyllis W. Speiser, New York University, New York, N.Y. (*co-chairs)


The Journal of Clinical Endocrinology and Metabolism | 2010

A Novel Ultrapressure Liquid Chromatography Tandem Mass Spectrometry Method for the Simultaneous Determination of Androstenedione, Testosterone, and Dihydrotestosterone in Pediatric Blood Samples: Age- and Sex-Specific Reference Data

Alexandra Kulle; Felix G. Riepe; D. Melchior; Olaf Hiort; P.-M. Holterhus

CONTEXT Current immunoassays for analysis of plasma androgens in children have several limitations due to antibody-specific variations of data and normal ranges. Mass spectrometry-based methods are available for individual steroids but need complex sample preparation and report only fragmentary reference data for the pediatric population. OBJECTIVE Our objective was to develop a state of the art sensitive and specific tandem mass spectrometry method for high-throughput simultaneous determination of plasma concentrations of androstenedione (A), testosterone (T), and dihydrotestosterone (DHT) and to report age-, sex-, and pubertal stage-specific reference levels for these steroids in children aged 0-18 yr. SUBJECTS AND METHODS Plasma (100 microl) was mixed with internal standard and extracted by solid-phase extraction. Androgens were measured by ultrapressure liquid chromatography tandem mass spectrometry. Samples of 138 boys and 131 girls with neither signs of endocrine nor systemic disease were considered for the generation of reference data. The following age groups were used: less than 1 wk, 2 wk to 2 months, 3-5 months, 6-11 months, 1-3 yr, 4-6 yr, 7-9 yr, 10-12 yr, 13-15 yr, and over 16 yr. RESULTS Lower quantification limit was 2.9 ng/dl (0.1 nmol/liter) for A, T, and DHT. No relevant interference with other steroids was detected. Reference data for A, T, and DHT are reported as functions of age, sex, pubertal maturation, and testicular volume. CONCLUSION Simplicity, velocity, sensitivity, specificity, and the availability of pediatric reference data allow application of our new method in clinical routine as well as in research settings.


Hormone Research in Paediatrics | 2009

Clinical and molecular features of type 1 pseudohypoaldosteronism.

Felix G. Riepe

Pseudohypoaldosteronism (PHA) is a rare heterogeneous syndrome of mineralocorticoid resistance causing insufficient potassium and hydrogen secretion. PHA type 1 (PHA1) causes neonatal salt loss, failure to thrive, dehydration and circulatory shock. Two different forms of PHA1 can be distinguished on the clinical and genetic level, showing either a systemic or a renal form of mineralocorticoid resistance. This review provides an overview on transepithelial sodium reabsorption and on clinical features and the underlying molecular pathology of systemic and renal PHA1 caused by mutations in the subunit genes (SCNN1A, SCNN1B, SCNN1G) of the epithelial sodium channel (ENaC) and the mineralocorticoid receptor coding gene NR3C2. The in vitro investigation of several mutants has resulted in important progress in the understanding of the physiology of ENaC and the mineralocorticoid receptor. Some mutations are discussed in more detail to demonstrate some of these findings. A better clinical work-up of the patients suffering from PHA1 may delineate additional associations between the genotype and phenotype in the future.


Reviews in Endocrine & Metabolic Disorders | 2007

Recent advances in diagnosis, treatment, and outcome of congenital adrenal hyperplasia due to 21-hydroxylase deficiency

Felix G. Riepe; Wolfgang G. Sippell

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21-OHD) is an autosomal-recessive disease causing cortisol deficiency, aldosterone deficiency and hyperandrogenism. Diagnosis of 21-OHD is confirmed by steroid analysis in newborn screening or later on. Standard medical treatment consists of oral glucocorticoid and mineralocorticoid administration in order to suppress adrenal androgens and to compensate for adrenal steroid deficiencies. However, available treatment is far from ideal, and not much is known about the long-term outcome in CAH as trials in patients in adulthood or old age are rare. Here we briefly describe the pathophysiology, clinical picture, genetics and epidemiology of 21-OHD. This is followed by a comprehensive review of the recent advances in diagnosis, treatment and outcome. Novel insights have been gained in the fields of newborn screening, specific steroid measurement utilizing mass spectrometry, genetics, glucocorticoid stress dosing, additive medical therapy, prenatal treatment, side-effects of medical treatment, adrenomedullary involvement, metabolic morbidity, fertility and gender identity. However, many issues are still unresolved, and novel questions, which will have to be answered in the future, arise with every new finding.


Hormone Research in Paediatrics | 2002

Management of Congenital Adrenal Hyperplasia: Results of the ESPE Questionnaire

Felix G. Riepe; Nils Krone; Matthias Viemann; Carl-Joachim Partsch; Wolfgang G. Sippell

The management of children and adolescents with congenital adrenal hyperplasia (CAH) remains difficult. To assess the current European practice in diagnosis and management of CAH, an ESPE (European Society for Paediatric Endocrinology) survey was circulated in 2000/2001. The questionnaire was answered by 34% of ESPE members, representing 125 institutions which cared for 6,553 CAH patients. Paediatric endocrinologists, surgeons, gynaecologists, geneticists, and psychologists are involved in the immediate care of the CAH neonate and his family. 44% of centres take part in neonatal screening programmes. In families at risk, prenatal dexamethasone therapy is started at a median gestational age of 6 weeks in a median dose of 20 µg/kg/day. 53% reported maternal adverse events, 8% observed adverse fetal events. Regarding feminizing surgery, 33% reported simultaneous clitoric reduction and vaginoplasty during infancy. However, clitoridectomy is still reported by 13% of centres, and vaginal dilatations have been performed by 27%. Although 71% of female CAH patients with psychosexual problems, only 17% undertake routine psychodiagnostics and counselling. Hydrocortisone is the substance used for the treatment of CAH during growth in 84%; the median dose (mg/m²/day) is 17.5 in infants, 15 in children and adolescents, and 13.75 in adults. The glucocorticoid dose is increased two- to sixfold during intercurrent stress. Mineralocorticoid is administered in cases of clinically manifest salt wasting and of elevated plasma renin activity, to decrease high glucocorticoid doses, or according to genotype. All participating ESPE members feel the need for further improvement in prenatal diagnosis and treatment, compliance during puberty, screening programmes, psychological aspects, and corrective surgery.


Hormone Research in Paediatrics | 2013

Implementation of a Liquid Chromatography Tandem Mass Spectrometry Assay for Eight Adrenal C-21 Steroids and Pediatric Reference Data

Alexandra Kulle; Maik Welzel; Paul-Martin Holterhus; Felix G. Riepe

Background: Sensitive and accurate determination of steroids is essential for diagnosing congenital and acquired adrenal diseases. Since plasma concentrations change during childhood, age-specific reference ranges are the prerequisite for clinical interpretation. The objectives of this study were to develop a sensitive and reliable method for simultaneous detection and quantification of progesterone, 17-hydroxyprogesterone, deoxycorticosterone (DOC), 11-deoxycortisol, 21-deoxycortisol, corticosterone, cortisol (F) and cortisone (E) by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) and to establish age- and sex-specific reference ranges from birth to adulthood. Methods: All eight steroids were measured simultaneously in 0.1 ml plasma by UPLC-MS/MS. Samples of 905 children were measured and grouped in five age groups. Results: The assay was linear up to 70 ng/ml (700 ng/ml for F; r2 > 0.992). The limit of detection ranged between 0.01 ng/ml for DOC and 0.07 ng/ml for E. Correlations with radioimmunoassays yielded a coefficient of determination between 0.82 and 0.99. Reference data are reported as a function of age and sex. Conclusions: The UPLC-MS/MS method presented here for the simultaneous detection of eight C-21 adrenal hormones together with the detailed reference ranges for children provides a valuable methodology for assessing adrenal steroids in clinical routine and research.


The Journal of Clinical Endocrinology and Metabolism | 2009

Steroid 17α-Hydroxylase Deficiency: Functional Characterization of Four Mutations (A174E, V178D, R440C, L465P) in the CYP17A1 Gene

Vivek Dhir; Nicole Reisch; Caroline Bleicken; Jan Lebl; Clemens Kamrath; Hans-Peter Schwarz; Joachim Grötzinger; Wolfgang G. Sippell; Felix G. Riepe; Wiebke Arlt; Nils Krone

CONTEXT Steroid 17alpha-hydroxylase (CYP17A1, alias P450c17) deficiency (17OHD) is a rare form of congenital adrenal hyperplasia. The CYP17A1 enzyme catalyzes two distinct reactions, 17alpha-hydroxylase and 17,20-lyase activities. OBJECTIVE The aim of the study was to analyze the structural and functional consequences of three novel (A174E, V178D, and L465P) and one previously reported (R440C) CYP17A1 mutation found in three patients clinically and biochemically presenting with 17OHD. PATIENTS AND METHODS Two patients suffering from 46,XY disordered sex development presented at ages 5.5 and 8.8 yr, respectively, with tall stature and hypertension. Mutation analysis revealed compound heterozygous CYP17A1 mutations (A174E/K388X; V178D/R440C). The third patient (46,XX) presented with primary amenorrhea and hypertension at age 15 yr. She was homozygous for the novel L465P mutation. Functional studies employing a yeast microsomal expression system compared wild-type and mutant CYP17A1 both with regard to 17alpha-hydroxylase and 17,20-lyase activity. Mutants were examined in a computational three-dimensional model of the CYP17A1 protein. RESULTS The activity assays showed that all three mutants retain only 0-7% of both 17alpha-hydroxylase and 17,20-lyase activity relative to CYP17A1 wild-type activity, corresponding to the in vivo situation. Enzyme kinetic studies proved the impairment of both reactions, respectively. Computer-based three-dimensional model analysis of CYP17A1 using CYP2B4 as template showed that three of the mutations had no direct effect on the active center, whereas one affects the heme coordination. CONCLUSION The functional studies revealed that the described missense mutations result in severe 17OHD. Our data are important to predict the phenotypic expressions and provide important information for patient management and genetic counseling.


Hormone Research in Paediatrics | 2004

Treatment of Pubertal Gynecomastia with the Specific Aromatase Inhibitor Anastrozole

Felix G. Riepe; Inka Baus; Stephanie Wiest; Nils Krone; Wolfgang G. Sippell; Carl-Joachim Partsch

Gynecomastia can be detected in up to 70% of boys during puberty and in about one third of adult males. An imbalance of estrogen to androgen tissue levels is believed to be the major reason for the development of gynecomastia; as a result most medical treatments so far have tried to lower the estrogen level. Five boys with pubertal gynecomastia and breast tenderness were treated for 6 months with the selective aromatase inhibitor anastrozole. Initial plasma levels of estradiol (E2), testosterone (T), androstenedione, dehydroepiandrosterone sulfate (DHEA-S) and gonadotropins were normal. DHEA-S showed a significant rise during treatment. T and androstenedione showed no significant change during treatment. E2 decreased with therapy, although to no statistically significant extent. The E2/T ratio decreased significantly during the treatment. Breast size decreased in 4 out of 5 patients, and in 1 of these 4 boys glandular breast tissue disappeared completely. The longer the duration of gynecomastia before anastrozole administration, the smaller was the reduction of breast size. Breast tenderness was resolved in all boys within 4 weeks. No adverse effects were recorded. Since the aim of medical treatment is the total disappearance of breast tissue, anastrozole, as previous aromatase inhibitors, is of limited effect. However, anastrozole seems to be of benefit for the treatment of tenderness in gynecomastia and for patients in whom surgery is particularly risky. However, as spontaneous disappearance of pubertal gynecomastia is common, further double-blinded, placebo-controlled trials are necessary before a definite conclusion can be drawn about the effectiveness and the side effects of this therapy.


The Journal of Clinical Endocrinology and Metabolism | 2013

Steroid Hormone Profiles in Prepubertal Obese Children Before and After Weight Loss

Thomas Reinehr; Alexandra Kulle; Barbara Wolters; Nina Lass; Maik Welzel; Felix G. Riepe; Paul-Martin Holterhus

CONTEXT Little information is available on the steroid hormone profiles in obese children and their changes after weight loss. OBJECTIVE We compared liquid chromatography-tandem mass spectrometry of serum steroid hormone profiles between obese and normal-weight children and studied the differential effects of weight loss on these hormones. DESIGN This study was a cross-sectional comparison between obese and normal-weight children and a longitudinal 1-year follow-up study during lifestyle intervention in obese children. SETTING The setting of the study was primary care. PATIENTS Forty obese prepubertal (mean age 8.5 ± 2.1 years, 48% female, mean body mass index 24.8 ± 3.5 kg/m(2)) and 40 normal-weight children matched for gender, age, and pubertal stage. INTERVENTION The study consisted of an outpatient 1-year intervention program based on exercise, behavior, and nutrition therapy. MAIN OUTCOMES MEASURES Progesterone, 17-hydroxyprogesterone, 11-deoxycorticosterone, corticosterone, aldosterone, 11-deoxycortisol, cortisol, cortisone, dehydroepiandrosterone sulfate (DHEAS), androstenedione, T, dihydrotestosterone, insulin resistance index of the homeostasis model assessment, and blood pressure were measured. RESULTS Prepubertal obese children showed significantly increased androgens (DHEAS, androstenedione, T), mineralocorticoid precursor corticosterone, and glucocorticoids (11-deoxycortisol, cortisol, cortisone) compared with normal-weight children. In contrast to 20 obese children without weight loss, the 20 obese children with substantial weight loss demonstrated a significant decrease of cortisol, cortisone, and corticosterone. Androstenedione and T decreased but DHEAS remained elevated. Changes of the homeostasis model assessment correlated significantly positively with changes of cortisol (r = 0.38) and cortisone (r = 0.43) in partial regression analyses adjusted to changes of weight status. CONCLUSIONS In obese prepubertal children, the increased androgens, mineralocorticoid precursors, and glucocorticoids were responsive to weight loss in contrast to DHEAS, suggesting that DHEAS does not seem to be regulated by changes in body mass index.


BMC Genomics | 2007

Intrinsic androgen-dependent gene expression patterns revealed by comparison of genital fibroblasts from normal males and individuals with complete and partial androgen insensitivity syndrome

Paul-Martin Holterhus; Uta Deppe; Ralf Werner; Annette Richter-Unruh; Jan-Hendrik Bebermeier; Lutz Wünsch; Susanne Krege; Hans Udo Schweikert; Janos Demeter; Felix G. Riepe; Olaf Hiort; James D. Brooks

BackgroundTo better understand the molecular programs of normal and abnormal genital development, clear-cut definition of androgen-dependent gene expression patterns, without the influence of genotype (46, XX vs. 46, XY), is warranted. Previously, we have identified global gene expression profiles in genital-derived fibroblasts that differ between 46, XY males and 46, XY females with complete androgen insensitivity syndrome (CAIS) due to inactivating mutations of the androgen receptor (AR). While these differences could be due to cell autonomous changes in gene expression induced by androgen programming, recent work suggests they could also be influenced by the location from which the fibroblasts were harvested (topology). To minimize the influence of topology, we compared gene expression patterns of fibroblasts derived from identical urogenital anlagen: the scrotum in normally virilized 46, XY males and the labia majora from completely feminized 46, XY individuals with CAIS.Results612 transcripts representing 440 unique genes differed significantly in expression levels between scrotum and CAIS labia majora, suggesting the effects of androgen programming. While some genes coincided with those we had identified previously (TBX3, IGFBP5, EGFR, CSPG2), a significant number did not, implying that topology had influenced gene expression in our previous experiments. Supervised clustering of gene expression data derived from a large set of fibroblast cultures from individuals with partial AIS revealed that the new, topology controlled data set better classified the specimens.ConclusionInactivating mutations of the AR, in themselves, appear to induce lasting changes in gene expression in cultured fibroblasts, independent of topology and genotype. Genes identified are likely to be relevant candidates to decipher androgen-dependent normal and abnormal genital development.

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Nils Krone

University of Birmingham

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