Dietmar Roesner

Association between c135G/A genotype and RET proto-oncogene germline mutations and phenotype of Hirschsprung's disease.

BACKGROUND Several genes, including the major susceptibility gene RET, have roles in development of Hirschsprungs disease. Results of genetic-linkage analysis of patients with familial disease with both long-segment and short-segment phenotypes have shown close linkage with the RET locus. We aimed to investigate whether both RET mutations and polymorphisms contribute to phenotype of Hirschsprungs disease. METHODS We looked at the coding region of all 21 exons of the RET proto-oncogene, including the flanking intronic sequences, by direct DNA sequencing in 76 caucasians from Germany with Hirschsprungs disease. FINDINGS 20 different mutations were detected in 18 patients. Mutations were under-represented in patients with a homozygous RET c135A/A genotype in association with short-segment phenotype. Short-segment phenotype also arose if the RET mutation was on the c135A allele; conversely, a RET germline mutation on the c135G allele resulted in long-segment phenotype, particularly in heterozygous c135G/A patients. INTERPRETATION These observations lend support to the idea that both RET alleles have a role in pathogenesis of Hirschsprungs disease, in a dose-dependent fashion. We also showed that the c135G/A polymorphism modifies the phenotype by a within-gene interaction between the c135A variant and a mutation.

Association of germline mutations and polymorphisms of the RET proto-oncogene with idiopathic congenital central hypoventilation syndrome in 33 patients

The idiopathic congenital central hypoventilation syndrome (CCHS) was first described by Mellins et al 1 and is characterised by an alteration of the ventilatory response to hypercapnia and hypoxia.1 Whereas normal ventilation is adequate in many of the patients during wakefulness, the alveolar hypoventilation observed during sleep seems attributable to a failure of the central autonomic control of ventilation in the brainstem.2 CCHS is a rare entity in which affected children show symptoms typically in the newborn period. These symptoms include a period of cyanosis upon sleep induction, a decrease of oxyhaemoglobin saturation with simultaneous life threatening increase of the partial pressure of CO2 in arterial blood (PaCO2), which yields no respiratory response, and no arousal reflex by the infants. Primary neuromuscular, lung, or cardiac disorders or an identifiable brainstem lesion are absent.3 The first extensive series of CCHS patients was described by Weese-Mayer et al 4 in 1992. The apparent functional defect possibly stems from an abnormal migration or differentiation of neural crest derived cells into the autonomic ventilatory control system. Therefore, idiopathic congenital central hypoventilation syndrome may be regarded as a feature of complex neurocristopathies, as confirmed by the observation of a combination of CCHS and other neurocristopathies.5 Specifically, CCHS has been reported in association with neoplastic as well as dysgenetic neurocristopathies, such as neuroblastomas6 and ganglioneuromas,7 but the frequency of such cases is lower than 5%. Furthermore, in 16-20% of the patients, CCHS is combined with Hirschsprung disease (HSCR), a developmental disorder characterised by congenital absence of ganglion cells in the myoenteric and submucosal plexuses of the bowel.6,8–16 Although most CCHS cases are sporadic, a putative genetic origin for CCHS has also been considered because of the familial occurrence in several reported cases, such as monozygotic …

Preliminary report on elective preterm delivery at 34 weeks and primary abdominal closure for the management of gastroschisis.

INTRODUCTION We aimed to critically evaluate elective preterm delivery and immediate abdominal wall closure and other techniques for the management of gastroschisis, hypothesizing that the advantages of an elective preterm delivery outweigh possible complications related to prematurity at birth. PATIENTS AND METHODS 13 gastroschisis patients were enrolled in the elective preterm delivery program (Group 1) since 1999. Patients were delivered by cesarean section in the 34th gestational week, with immediate primary closure of the defect. Data regarding parameters at and after birth were compared with a historical control group of 10 patients conventionally managed for gastroschisis in a similar period (1994 - 1999) (Group 2). The primary endpoints of this study were the initiation of oral feeding and the length of hospital stay. RESULTS There was a significantly faster initiation of oral feeding (p = 0.0012) and a shorter hospital stay (p = 0.0160) in Group 1. The postoperative outcome was excellent in all patients. Acute and late complications were fewer and less severe in Group 1 and none were related to prematurity. CONCLUSIONS Elective preterm delivery appears to be an effective method for the management of gastroschisis, and a method whose advantages thus far have outweighed the possible complications due to prematurity.

Compound effect of PHOX2B and RET gene variants in congenital central hypoventilation syndrome combined with Hirschsprung disease

Guido Fitze,* Inke R. König, Ekkehart Paditz, Alexandre Serra, Marianne Schläfke, Dietmar Roesner, Andreas Ziegler, and Hans K. Schackert Department of Pediatric Surgery, University of Technology Dresden, Dresden, Germany Department of Pediatrics, University of Technology Dresden, Dresden, Germany Department of Surgical Research, University of Technology Dresden, Dresden, Germany Institute of Medical Biometry and Statistics, University at Lübeck, Lübeck, Germany Department of Applied Physiology, Ruhr-University Bochum, Bochum, Germany

Rare occurrence of PHOX2b mutations in sporadic neuroblastomas.

Neuroblastomas (NBs) are frequent solid tumors in childhood for which no specific genetic marker linked to their development has been identified to date. PHOX2b, which regulates the autonomic neuron development, has been associated with the development of autonomic diseases, and has been considered a potential candidate gene for neural crest-derived tumors such as NB. To ascertain the role of the PHOX2b gene in NB development, we have sequenced the complete PHOX2b coding region in tumors from 69 patients with sporadic NB, while 130 blood donors served as negative controls and 9 NB cell lines as positive controls. We found a missense deletion in exon 3 in a cell line. A further silent mutation in exon 3 (c.870C>A) was observed in 3 tumors but in none of the controls. A new polymorphism in intron 1 (IVS1-114 G>A) was observed in 31 tumor samples (44.9%) and in 68 controls (52.3%). We did not find any conclusive association of the polymorphisms or mutations in PHOX2b with the development of NB, although the large confidence intervals neither substantiate nor exclude a role for this gene in the tumor etiology.

Interaction of RET proto-oncogene codon 609 germline mutations with RET haplotypes characterized by c.135G>A alleles modifying MEN 2A or HSCR phenotypes

Germline mutations of the RET proto-oncogene have been identified in patients with the inherited neoplastic syndrome ‘‘multiple endocrine neoplasia type 2’’ (MEN 2, [MIM no. 171400]), which comprises themedullary thyroid carcinoma as an obligatory feature, and with Hirschsprung disease (HSCR [MIM no. 142623]), a developmental disorder of the enteric nervous system characterized by the absence of intramural ganglia in the hindgut. Highly penetrant germline missense mutations of RET proto-oncogene have been detected in each one of six cysteine codons within exon 10 (codons 609, 611, 618, and 620) and exon 11 (codons 630 and 634) in about 95% of MEN 2A and in up to 85% of familial medullary thyroid carcinoma (FMTC) families [Donis-Keller et al., 1993; Mulligan et al., 1993; Eng andMulligan, 1997]. In contrast, between 10 and 40% of the patients with HSCR harbor germline mutations of the RET proto-oncogene, which are primarily point mutations scattered throughout the extracellular domain and within the intracellular tyrosine kinase domain of RET [Edery et al., 1994; Romeo et al., 1994; Angrist et al., 1995; Attie et al., 1995; Seri et al., 1997]. The phenotypic association of MEN 2A/FMTC and HSCR was previously reported in several kindreds. With one exception, this combined phenotype segregates in the involved families with a single RET haplotype harboring a cysteine germline mutation of the codons 609, 618, or 620 [Mulligan et al., 1994]. Since all of these RET germline mutations are described in various families in association withMEN 2A/FMTC alone, and assuming a genetically determined HSCR phenotype, additional genetic alterations resulting in a combination of the MEN 2 and HSCR phenotype can be hypothesized. The present study describes two unrelated kindreds with codon 609 RET mutations associated with different phenotypes and different alleles at an intragenic single nucleotide polymorphic site in exon 2. We analyzed the RET proto-oncogene in two families both harboring a codon 609 RET germline mutation. The only affected individual of the first family (Fig. 1a) has a de novo mutation in association with HSCR, without any of the expected MEN2 features. In the second family, the mutation segregates with the more characteristic MEN2A phenotype (Fig. 1b). Genomic DNA was extracted from leukocytes from peripheral venous blood samples by standard protocols. The amplification and sequencing of all 21 RET exons was performed using primers and reaction conditions described previously [Ceccherini et al., 1994;Mulligan et al., 1994;Fitze et al., 2002]. Furthermore, we determined the genotypes of seven polymorphisms of the coding region of the RET proto-oncogene in all family members [Ceccherini et al., 1994; Fitze et al., 1999]. Direct DNA sequencing of all 21 coding exons of the RET proto-oncogene, including the adjacent intronic boundaries, detected a heterozygous germline mutation of codon 609 (TGC!AGC) in the HSCR affected patient (II-1, Fig. 1a) of the first family. This mutation results in the substitution of a cysteine amino acid residue by serine. In this patient, an additional germline mutation was not found and all clinically unaffected family members were excluded as gene carriers. In the index case, the homozygous c.135A genotype, the heterozygous c.2307T/G genotype, and for all others (c.375C, c.1296G, c.2071G, c.2508C, c.2712C) the homozygous wildtype genotypes were found in the analysis of the coding region polymorphisms. Hence, the C609S mutation was located on a c.135A allele. The genotypes in this family are shown in Figure 1a. In contrast, the index case of the second family (II-2, Fig. 1b) also harbored a heterozygous germline mutation of the codon 609 (TGC!GGC), resulting in a substitution of cysteine by glycine. In this family theC609Gmutation segregatedwith the MEN 2A phenotype. Six of seven identified gene carriers underwent total thyroidectomy, and five were diagnosed with MTC. Only a 5-year-old boy (IV-4) showed a normal thyroid gland histology after prophylactic thyroidectomy. Two of the gene carriers (II-2, II-4) also had a pheochromocytoma. Moreover, the polymorphisms, particularly c.135G>A and c.2307T/G, showed the homozygous wild-type genotype (c.135G, c.375C, c.2071G, c.2307T, c.2508C, c.2712C), with exception of c.1296G>A polymorphism, which was heterozygous in five of seven C609G gene carriers (Fig. 1b). Hence, the C609G mutation was located on a c.135G allele. Whereas the family harboring the C609G (TGC!GGC) mutation showed a typical MEN 2A syndrome without clinical signs ofHSCRor chronic constipation over three generations, a novel de novo C609S (TGC!AGC)mutation in one individual was associated with isolated short-segment HSCR. A prophylactic thyroidectomy at age 30 revealed neitherMTCnor C-cell hyperplasia. Isolated HSCR in association with a common MEN 2 cysteine codon mutation involving either codon 609 (three cases) or codon620 (one case) is relatively rare [Mulligan etal., 1994;Angrist et al., 1995;Hofstra, 1998].Yet, coexistence of MEN 2 and HSCR phenotypes segregating with a specific RET allele harboring RET mutations of codons 609, 618, and 620 have been shown in 21 reported families [Chretien et al., 1994;Mulligan et al., 1994;Borst et al., 1995;Blanket al., 1996; Caron et al., 1996; Peretz et al., 1997; Seri et al., 1997; Borrego et al., 1998; Decker et al., 1998; Fitze et al., 2002; Pasini et al., 2002]. Because of the contrasting character of RETmutations in theMEN2 or theHSCRphenotype (gain of function inMEN 2-associated RET mutations versus loss-of-function in HSCRassociated RET mutations), it may be assumed that the combined HSCR/MEN 2 phenotype derives from two different RET germline mutations. However, second RET mutations *Correspondence to: Dr. Guido Fitze, M.D., Department of Pediatric Surgery, University of Technology Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany. E-mail: Guido.Fitze@mailbox.tu-dresden.de

Unfallumstände und Unfallfolgen

Anhand der differenzierten Analyse der Unfallumstande der mit dem grosten Risiko behafteten Tatigkeiten und ihrer Verletzungsfolgen konnen weitere Ruckschlusse fur eine effektive Pravention abgeleitet werden. Zunachst werden die medizinischen Folgen der erfassten Unfalle fur die unterschiedenen Unfallkategorien Schul-, Freizeit-, Verkehrsunfall, einschlieslich der Unterscheidung von Schulsport- und Freizeitsportunfallen, vorgenommen. Anschliesend werden die medizinischen Unfallfolgen der ermittelten Unfallschwerpunkte Radfahren, Klettersturze, Ballspiele, Reiten Inlineskaten, Wintersport, Mopedfahren und andere Verkehrsunfalle differenziert dargestellt. Abgeschlossen wird dieser Abschnitt mit einer Betrachtung der Rettungskette (als Teil der sekundaren Pravention) und einer Untersuchung der Bemuhungen der betroffenen verunfallten Kinder und Jugendlichen und ihrer Familien, die Folgen des Unfalls psychisch und physisch zu verarbeiten (tertiare Pravention).

Hat die akute Appendizitis im Kindesalter einen genetischen Hintergrund

Appendectomies are some of the most frequently performed operations in children, with highest incidence around the 10th year of life. The etiology of appendicitis is multifactorial, yet in essence there is an insufficient drainage leading to inflammation within the appendix, which may very well be caused by an alteration of the intramural innervation and subsequent decreased peristalsis of the organ. Additionally, a familial occurrence of this disease has been observed, which together with the plausible pathological mechanisms suggest that there may be a connatal and genetically determined predisposition for appendicitis. A typical childhood disorder characterized by absent peristalsis due to altered enteric innervation is Hirschsprung disease, which is often caused by a germline mutation in the RET proto-oncogene. Therefore, we hypothesized that the RET proto-oncogene has also an impact in the etiology of the acute appendicitis in children.

Assoziation von Keimbahnmutationen im RET-Protoonkogen mit dem sporadischen Adenokarzinom des Magens

The diffuse type of gastric carcinoma is occasionally associated with germline mutations of the E-cadherine gene, and it has also been described in families with Li-Fraumeni syndrome or other polyposis syndromes including FAP.

Popliteal-artery-entrapment-Syndrom Kasuistik eines 11jährigen Knaben

The popliteal entrapment syndrome arises due to a compression of the popliteal artery by tendomuscular structures often combined with an anomal position of the artery. Mostly young men are complaining of this disease. We report about an eleven-year old boy, who had an interview with us because of acute ischaemic symptoms in the left shank. We ensured a popliteal entrapment syndrome type I by Kogel. By a dorsal approach to the fossa poplitea we performed the myotomy and the restoration of the artery into the normal position. Eight month postoperative the boy is without any complaint. In doppler-scan we record an normal arterial flow.ZusammenfassungDas popliteale Entrapmentsyndrom ist bedingt durch eine Kompression der A. poplitea durch tendomuskuläre Strukturen, meist gepaart mit einer Lageanomalie der Arterie. Überwiegend leiden junge Männer an diesem Krankheitsbild. Es wird hier über den Fall eines 11jährigen Knaben berichtet, der sich mit akuten ischämischen Beschwerden im linken Unterschenkel vorstellte. Diagnostisch wurde ein popliteales Entrapmentsyndrom Typ I nach Kogel geischert. Therapeutisch erfolgte die dorsale Freilegung der Fossa poplitea mit Myotomie und Normalverlagerung der A. poplitea. Acht Monate nach erfolgter Operation ist der Knabe klinisch beschwerdefrei, es stellt sich dopplersonographisch ein normales arterielles Flußmuster dar.