c-Ret-mediated hearing loss in mice with Hirschsprung disease.

A significantly increased risk for dominant sensorineural deafness in patients who have Hirschsprung disease (HSCR) caused by endothelin receptor type B and SOX10 has been reported. Despite the fact that c-RET is the most frequent causal gene of HSCR, it has not been determined whether impairments of c-Ret and c-RET cause congenital deafness in mice and humans. Here, we show that impaired phosphorylation of c-Ret at tyrosine 1062 causes HSCR-linked syndromic congenital deafness in c-Ret knockin (KI) mice. The deafness involves neurodegeneration of spiral ganglion neurons (SGNs) with not only impaired phosphorylation of Akt and NF-kappaB but decreased expression of calbindin D28k in inner ears. The congenital deafness involving neurodegeneration of SGNs in c-Ret KI mice was rescued by introducing constitutively activated RET. Taken together with our results for three patients with congenital deafness with c-RET-mediated severe HSCR, our results indicate that c-Ret and c-RET are a deafness-related molecule in mice and humans.

Radiological findings in total colon aganglionosis and allied disorders.

OBJECTIVE: The aim of this study was to review the radiological findings of three cases of total colon aganglionosis (TCA), hypoganglionosis, and immature ganglionosis, and to compare the differences in diagnosis and follow-up of these three disease entities. MATERIALS AND METHODS: Three neonates with neonatal onset of abdominal distension with vomiting were investigated, and the cases were diagnosed as TCA, hypoganglionosis, and immature ganglionosis, respectively. Radiological examination of each neonate was performed during the neonatal period and at follow-up. RESULTS: A plain abdominal radiograph showed massive abdominal bowel gas and multiple air-fluid levels in all cases. Barium enema findings including no transition zone, normal rectosigmoid index, reflux of barium into a dilated ileum, and retention of barium on delayed film were observed in all three cases. In aganglionosis and hypoganglionosis, a normal-sized colon, irregular contraction, shortening of the colon, and lack of redundancy were observed. In immature ganglionosis, microcolon was present but there was no shortening of the colon or loss of redundancy. Barium studies following ileostomy during childhood revealed no efficient peristalsis after the neonatal period in patients with aganglionosis and hypoganglionosis. Conversely, the patient with immature ganglionosis showed maturity of colonic function on barium studies after infancy. CONCLUSION: The clinical and radiological findings of TCA and allied disorders are similar in neonates. Sequential contrast intestinal studies could reveal peristalsis of the colon wall, suggesting maturity of the ganglion cells.

Duodenal perforation associated with norovirus and rotavirus gastroenteritis.

KEY CLINICAL MESSAGE: Norovirus (NoV) and rotavirus (RV) gastroenteritis are usually self-limiting. However, few pediatric cases of bowel perforation and no duodenal perforation with NoV gastroenteritis were reported. We describe two children with duodenal perforation due to NoV or RV gastroenteritis. Suspicion for this association enables prompt intervention, preventing lethal outcomes of these common infections.

Neuroglial disorders of central and peripheral nervous systems in a patient with Hirschsprung's disease carrying allelic SOX10 truncating mutation.

BACKGROUND/PURPOSE: Recent biologic studies have revealed that enteric neuroglial deficiency causes gut functional deterioration. We studied the central and peripheral nervous systems in a SOX10 mutation-associated Hirschsprung's patient who presented persistent gut functional disorders even after definitive surgery. METHODS: DNA sequences of all coding regions of the SOX10 gene (22q13) were determined using the direct DyeDeoxy Terminator Cycle method, and brain magnetic resonance images, nerve conduction velocities, and histopathology of the enteric nervous system were investigated for neurologic assessment. RESULTS: DNA analysis revealed a heterozygous nucleotide deletion (778delG) in SOX10 exon 5, causing a frameshift at codon 260 and resulting in premature transcriptional termination at codon 285. Neurologic studies disclosed brain hypomyelination, peripheral dysmyelinating neuropathy, and enteric neuroglia deficiency, which exclusively implied systemic glial maldevelopment. CONCLUSION: These results suggest that the enteric nervous system in patients with SOX10-associated Hirschsprung's disease is entirely subject to neuroglial impairment. This may explain persistent gut motility and absorption insufficiency after pull-through surgery, especially in children with allelic SOX10 truncating mutations.

Infrared spectrophotometry of intraluminal meconium calculi in a neonate with imperforate anus and rectourethral fistula.

BACKGROUND/PURPOSE: Intraluminal meconium calculi are a rare cause of neonatal abdominal calcifications in patients with anorectal malformations. To investigate their pathogenesis, we performed infrared spectroscopic analysis of meconium-calcified lesions. METHODS: Meconium calculi were collected from the colostomy in a newborn patient with imperforate anus and rectourethral fistula. The potassium bromide method was employed to obtain the infrared absorption spectrum of the meconium calculi. RESULTS: The wavelength pattern of the meconium calculi exhibited 4 specific peaks at 1570, 1390, 1105, and 1005 cm(-1) between 22% and 45% transmittance values. The unique absorption spectrum exclusively indicated ammonium hydrogen urate (C(5)N(5)O(3)H(7)), having the combined constituents of ammonium and uric acid. CONCLUSIONS: These results suggest that the intraluminal meconium calculi were originally derived from meconium and fetal urine. The stasis of meconium passage and fetal urine mixing through the rectourethral fistula in a low-pH condition was deduced to be the main cause of this rare stone formation.

Developmental study of tethered spinal cord in murine embryos with anorectal malformations.

BACKGROUND/PURPOSE: Tethered spinal cord is frequently associated with anorectal malformations (ARMs). However, it remains unknown how the tethered spinal cord develops and relates to the severity of ARM. We studied the development of the spinal cord in ARM mouse embryos induced by all-trans retinoic acid (ATRA). METHODS: Pregnant ICR-Slc mice were administered 100 mg/kg of ATRA on the ninth embryonic day (E9.0). Embryonic specimens were obtained from the uteri between E11.0 and E18.5. Midsagittal histologic sections focusing on the spinal cord and pelvis were prepared for immuonhistochemistry specific for neurofilament and Protein Gene Product 9.5 molecules. RESULTS: More than 98% of ATRA-treated embryos demonstrated ARM with rectourethral or rectocloacal fistula. Normal embryos exhibited progressive ascent of the spinal cord from E14.5. However, in ARM embryos, the distal spinal cord ended with meningomyelocelelike or atypical hamartomatous lesions at E11.5 to E13.5, which later caused stretch force that damaged the spinal cord, resulting in tethered cord between E16.0 and E16.5. CONCLUSIONS: In ATRA-induced ARM mouse embryos, tethered spinal cord was mostly established, accompanied by caudal neural maldevelopment, during early fetal development. This experimental model may be useful for researching detailed neuropathologic conditions in ARM children accompanied with tethered spinal cord.

Neurocutaneous melanosis associated with Hirschsprung's disease in a male neonate.

Hirschsprung's disease is an inherited disorder characterized by the absence of ganglion cells in the distal bowel. Neurocutaneous melanosis is a rare congenital syndrome characterized by proliferation of melanin-producing cells in the skin and leptomeninges. The authors described a newborn patient with neurocutaneous melanosis associated with Hirschsprung's disease. This male baby had congenital hydrocephalus, large and multiple pigmented skin nevi, and severe abdominal distension. He showed marked hydrocephalus at birth and underwent a ventriculo-peritoneal shunt at the age of 5 days. Investigations for gut motility disorders revealed typical findings consistent with Hirschsprung's disease involving the rectosigmoid colon. He was surgically treated for Hirschsprung's disease after transanal endorectal pull-through at the age of 7 months. After settlement of the ventriculo-peritoneal shunt, the transanal approach was of significant value for keeping the intraperitoneal catheter clean. The association of developmental disorders of melanocytes and enteric ganglia, both of which originated from the neural crest, suggested the presence of mutual pathogenetic factors in the patient.

Impaired expression of myogenic regulatory molecules in the pelvic floor muscles of murine embryos with anorectal malformations.

BACKGROUND/PURPOSE: Recent biological studies have elucidated the molecular mechanism of muscle development, in which various regulatory factors (myogenic regulatory factors [MRFs]) play key roles during embryogenesis. To investigate the development of anorectal malformations (ARMs), we studied MRF expressions in myogenic cells in the pelvic floor using murine embryos affected with ARM. METHODS: Anorectal malformation embryos were obtained from the 10.5th embryonal day (E10.5) to the 7.0th postnatal day (D7.0) in a natural mutant strain (Sd/+, RSV/Le). Serial frozen sections were prepared for immunohistochemistry using specific antibodies to M-cadherin, myoD, Myogenin, myosin heavy chain, and alfa-actin molecule. RESULTS: In normal mice, embryonal caudal somites differentiated into myogenic stem cells and migrated to the pelvic floor between E11.0 and E14.0. In the ARM mice, however, caudal somites were irregularly arranged and MRF expressions in myogenic cells were markedly decreased in the dorsocaudal region at E11.5 to E13.0, leading to hypoplastic pelvic floor muscles. CONCLUSIONS: The maldevelopment of pelvic floor muscles in ARM is derived from a deficient supply of myogenic stem cells, with impaired MRF expression. These results suggest that myogenic stem cells, available from bone marrow contents, may be used for postnatal muscle regeneration to reinforce the pelvic floor muscle function in children with ARM.

Iodine 123 metaiodobenzylguanidine radio-guided navigation surgery for recurrent medullary thyroid carcinoma in a girl with multiple endocrine neoplasia type 2B.

Multiple endocrine neoplasia type 2B (MEN 2B) is an inherited cancerous syndrome characterized by medullary thyroid carcinoma (MTC), adrenal pheochromocytoma, marfanoid habitus, and enteric ganglioneuromatosis. In this syndrome, a high frequency of persistent elevation of the serum calcitonin level, a sensitive marker for MTC, after total thyroidectomy has been reported, and the prognosis of such patients depends upon complete resection of recurrent MTC by repeated surgery. The authors performed iodine 123 metaiodobenzylguanidine ((123)I-MIBG) radio-guided navigation surgery for recurrent MTC in a 14-year-old girl with MEN 2B. She had undergone 4 neck operations, including total thyroidectomy at the age of 7 years. An intravenous injection of 100 MBq (123)I-MIBG was followed by the fifth surgery. At surgery, the cervical and upper mediastinal areas were filled with adhesional scar tissue, in which a gamma-scintillation probe conducted hot spots of isotope uptake by cancerous cells. Histopathology of resected specimens showed scattered nests of MTC cells corresponding to gamma-scintillation counts. Intraoperative (123)I-MIBG scanning is of substantial benefit for children with MEN 2B undergoing surgery for recurrent MTC.

Mucoepidermal carcinoma of the lung detected by positron emission tomography in a 5-year-old girl.

The authors describe a rare case of mucoepidermal carcinoma of the lung incidentally identified in preoperative assessments for inguinal hernia repair in a 5-year-old girl. This patient was referred for right external inguinal hernia, and a 3.0-cm round-shaped lesion was found in the right lower lung field of a chest x-ray film. She had no respiratory tract complaints, but her serum carcinoembryonic antigen concentration was markedly elevated (21.2 ng/mL). Chest and abdominal computed tomography/magnetic resonance images could not determine the nature of the lesion, but 2-[18 F]fluoro-2-deoxy- d -glucose positron emission tomography (FDG-PET) indicated a malignant tumor pattern. The patient underwent a computed tomography-guided needle biopsy of the lesion (S8), which was soon followed by a right lower pulmonary lobectomy. Histopathology of the resected specimen showed mucoepidermal carcinoma with no regional lymph node metastasis. In childhood asymptomatic pulmonary lesions, it is often difficult to rule out the possibility of malignancy. In the present case, FDG-PET scanning appropriately indicated the therapeutic priority of pediatric thoracic surgery.

Respiratory insufficiency in a newborn with mesenchymal hamartoma of the chest wall occupying the thoracic cavity.

The authors describe a newborn patient with mesenchymal hamartoma of the chest wall associated with pulmonary hypoplasia. A massive thoracic tumor was diagnosed by prenatal ultrasonography and magnetic resonance imaging at the 28th week of gestation. She was delivered through cesarean delivery at the 36th gestational week. Respiratory distress because of pulmonary hypoplasia necessitated neonatal intensive care. The tumor extensively involved the left hemithorax including all 12 ribs and the first 10 thoracic vertebrae, resulting in marked deformity of the thorax. At 5 days of age, she underwent the incisional biopsy through a left thoracotomy. Histopathology of biopsy specimens showed multiple components of mesenchymal origin including premature cartilage, bone, and cystic lesions resembling aneurysmal bone cyst. The tumor then showed a rapid overgrowth, but subsequently exhibited a self-limited growth for months, in which her respiratory condition gradually improved to spontaneous breathing without oxygenation support. The present case advocates perinatal preparations for associated pulmonary hypoplasia and conservative management for the neoplasm in fetuses prenatally diagnosed as having this unique pathological entity.

DPC-4 (Smad-4) and K-ras gene mutations in biliary tract epithelium in children with anomalous pancreaticobiliary ductal union.

BACKGROUND/PURPOSE: Recent studies have found that anomalous pancreaticobiliary ductal union (APBDU) is a substantial risk factor for biliary tract cancer at a younger age. DPC-4 (Smad-4) is a new tumor suppressor gene frequently inactivated in pancreatic and bile duct adenocarcinoma. To clarify carcinogenesis in APBDU, the authors investigated possible DPC-4 and K-ras mutations in 35 pediatric patients. METHODS: DNA was extracted from biliary tract epithelial cells, which were resected surgically and histologically purified using microdissection. Polymerase chain reaction (PCR) primers were designed specifically for exons 8-11 of DPC-4 (18q21.1) and exons 1-2 of the K-ras oncogene (12p12.1). DNA sequences were determined using the direct DyeDeoxy Terminator Cycle method. RESULTS: Of 35 children, 30 had wild-type DPC-4 and K-ras genes. K-ras mutations were detected in 5 patients, 4 of whom showed epithelial hyperplasia or metaplasia. In a 12-year-old girl with adenocarcinoma arising from a choledochal cyst, K-ras and DPC-4 (homozygous deletion) mutations were identified simultaneously. CONCLUSIONS: These results suggest that carcinogenesis in the biliary tract epithelium in APBDU is accompanied by multistep genetic mutational events; K-ras gene mutation occurs early in epithelial hyperplasia or metaplasia, whereas inactivation of the DPC-4 gene accumulates late in the progression of biliary tract adenocarcinoma.

Discrepancy between macroscopic and microscopic transitional zones in Hirschsprung's disease with reference to the type of RET/GDNF/SOX10 gene mutation.

BACKGROUND/PURPOSE: Recent studies have found that Hirschsrung's disease is caused by diverse genomic abnormalities. To clarify whether these pathogenic variations influence the distribution and function of enteric ganglia, the authors studied the morphology of the macroscopic and microscopic transitional zone in Hirschsprung's disease with reference to the type of genetic mutation. METHODS: In 120 patients with Hirschsprung's disease, the location and morphology of the gut caliber change were recorded, and the enteric nervous system was investigated histologically using biopsy specimens. The DNA sequences of all the RET/GDNF/NTN and SOX10 coding regions were determined using the direct DyeDeoxy Terminator Cycle method. RESULTS: In RET mutation carriers, the gut caliber change was almost identical to the histologic transition in cases of short segment aganglionosis, whereas these were markedly dissociated in cases exhibiting extensive aganglionosis. In contrast, SOX10 mutation carriers had a very long histologic transition and exhibited no caliber change. CONCLUSIONS: The type of genetic mutation responsible for Hirschsprung's disease influences the postnatal distribution and function of enteric ganglia. The data on discrepancy between macroscopic and microscopic transitions may enable us to concentrate the sites of the leveling biopsy more accurately especially in cases of long type intestinal aganglionosis carrying RET gene mutation.

Development of the pelvic floor muscles of murine embryos with anorectal malformations.

BACKGROUND/PURPOSE: Recent biological studies have elucidated the molecular mechanism of muscle development, in which various regulatory molecules play key roles during embryogenesis. To determine possible myogenic abnormalities in anorectal malformations (ARM), the authors investigated the pelvic muscle development in murine embryos affected with ARM. METHODS: ARM embryos were induced by all-trans retinoic acid (ATRA) on the ninth gestational day (E9.0). Embryonal specimens were obtained from the uteri between E10.5 and E16.0, and the frozen sections were prepared for immunohistochemistry using antibodies specific for MyoD, myogenin, and PGP9.5 molecules. RESULTS: In ARM embryos, the neural tube was irregularly branched and formed an anomalous mass in the sacral region. Embryonal caudal somites differentiated into myogenic cells to form proper myotubes in the pelvis corresponding to the developmental stages between E12.5 and E15.0 both in affected embryos and the controls. CONCLUSIONS: In ARM embryos, an impaired anatomic framework of the pelvis was caused by neural maldevelopment, whereas muscle development proceeded physiologically. These results support the hypothesis that pelvic floor muscles may function in ARM children, in whom neural abnormalities such as meningomyelocele or tethered spinal cord have been ruled out, if the surgical correction is appropriately completed.

Proximal jejunostomy with or without myectomy-myotomy modification in five infants with total intestinal aganglionosis: An experience with surgical treatments in a single institution.

BACKGROUND: Total intestinal aganglionosis is characterized by the absence of intramural ganglion cells, in which the disease's involvement extends from the stomach to the anorectum. This disease was suggested previously to be incompatible with life, but recently an extended small bowel myectomy-myotomy has achieved some prolonged survivors. METHODS: Five patients with total intestinal aganglionosis underwent laparotomy at 1 to 5 days of age. Surgery was performed as a simple jejunostomy 60 to 70 cm below the ligament of Treitz in the initial 2, jejunustomy 30 cm below the ligament of Treitz in 1, and jejunostomy with myectomy-myotomy modification 30 to 35 cm below the ligament of Treitz in the remaining 2 infants. RESULTS: The initial 2 patients died of sepsis, possibly derived from frequent enteritis and bacterial translocation at 7 and 8 months of age. Another patient had prolonged survival but died of hepatic failure at 1 year, 4 months. The remaining 2 children have survived beyond 2 years of age without any liver dysfunction, receiving a combination of enteral and parenteral nutrition. CONCLUSIONS: The more proximal site (30 to 35 cm below the ligament of Treitz) of jejunostomy with myectomy-myotomy modification appeared to be preferable for prolonged survival in these 5 patients with total intestinal aganglionosis.

SOX10 mutations in chronic intestinal pseudo-obstruction suggest a complex physiopathological mechanism.

The type IV Waardenburg syndrome (WS4), also referred to as Shah-Waardenburg syndrome or Waardenburg-Hirschsprung disease, is characterised by the association of Waardenburg features (WS, depigmentation and deafness) and the absence of enteric ganglia in the distal part of the intestine (Hirschsprung disease). Mutations in the EDN3, EDNRB, and SOX10 genes have been reported in this syndrome. Recently, a new SOX10 mutation was observed in a girl with a neural crest disorder without evidence of depigmentation, but with severe constipation due to a chronic intestinal pseudo-obstruction and persistence of enteric ganglia. To refine the nosology of WS, we studied patients with typical WS4 (including Hirschsprung disease) or with WS and intestinal pseudo-obstruction. We found three SOX10 mutations, one EDNRB and one EDN3 mutations in patients presenting with the classical form of WS4, and two SOX10 mutations in patients displaying chronic intestinal pseudo-obstruction and WS features. These results show that chronic intestinal pseudo-obstruction may be a manifestation associated with WS, and indicate that aganglionosis is not the only mechanism underlying the intestinal dysfunction of patients with SOX10 mutations.