Polymorphisms in genes involved in folate metabolism as risk factors for NTDs.

Moderate hyperhomocysteinemia in pregnant women has been associated with an increased risk of neural tube defects (NTDs). Periconceptional supplementation with multi-vitamins containing folic acid may normalize homocysteine metabolism and decrease the NTD risk. The C677 T variant of the MTHFR gene coding for a thermolabile enzyme has been described as the first genetic risk factor that accounts for a group of NTDs characterized by low maternal folate status and high homocysteine concentrations. Another common mutation of the same MTHFR gene, A1298 C, has also been described as an NTD risk factor. In addition to abnormal folate metabolism, anything that compromises the internalization of folate into the cell may be involved in the pathogenesis of NTDs. For this reason, a common polymorphism in the RFC-1 gene encoding the reduced folate carrier protein (A80 G) could also be an additional NTD risk factor. In the present study we examined the genotypic distributions and the allele frequencies of MTHFR A1298 C and RFC-1 A80 G polymorphisms in DNA samples from healthy Italian individuals and compared them to the frequencies observed in NTD cases and their parents. By means of restriction enzymatic analysis, we determined that the frequency of the mutated C allele of the A1298 C mutation was 0.25 among control individuals, which is in the range of that recently reported in other ethnic groups. However, we report that the mutant C allele frequencies are significantly higher among NTD cases and case mothers than among controls (0.39, 0.44, 0.25). Furthermore, for the RFC-1 A80 G mutation, we found that the frequency of the G allele of the RFC-1 mutation was 0.46 in the control population, suggesting that this is a common polymorphism in the Italian population. In spite of the high prevalence of the 80 G/G genotype among healthy subjects, we observed an increased frequency of the G allele in NTD-affected children, and their mothers and fathers. These preliminary results indicate that both the MTHFR and RFC-1 polymorphisms may play a role in NTD risk, at least in the Italian population. Further studies should be directed toward the evaluation of the level of risk conferred by the mutant MTHFR and RFC-1 genotypes, as well as the interaction between these genetic determinants and other nutritional and environmental factors.

Folate pathway gene alterations in patients with neural tube defects.

Periconceptional folate supplementation reduces the recurrence and occurrence risk of neural tube defects (NTD) by as much as 70%, yet the protective mechanism remains unknown. Inborn errors of folate and homocysteine metabolism may be involved in the aetiology of NTDs. Previous studies have demonstrated that both homozygosity for the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene, and combined heterozygosity for the C677T and for another mutation in the same gene, the A1298C polymorphism, represent genetic risk factors for NTDs. In an attempt to identify additional folate related genes that contribute to NTD pathogenesis, we performed molecular genetic analysis of folate receptors (FRs). We identified 4 unrelated patients out of 50 with de novo insertions of pseudogene (PS)-specific mutations in exon 7 and 3'UTR of the FRalpha gene, arising by microconversion events. All of the substitutions affect the carboxy-terminal amino acid membrane tail, or the GPI anchor region of the nascent protein. Furthermore, among 150 control individuals, we also identified one infant with a gene conversion event within the FRalpha coding region. This study, though preliminary, provides the first genetic association between molecular variations of the FRalpha gene and NTDs and suggests that this gene can act as a risk factor for human NTD.

Analyses of prognostic factors in a retrospective review of 92 children with ependymoma: Italian Pediatric Neuro-oncology Group.

The principal aim of this report is to present the results of multivariate analyses conducted to identify clinical prognostic factors in 92 children aged < 16 years with ependymoma (EPD) retrospectively collected in seven Italian centres. They were treated over a 16-year period (1977-1993). Treatment modalities varied. Surgery and radiotherapy (RT) was the "gold standard" management method for the majority of these children. Only in the late 1980s did some of them receive chemotherapy (CT), mainly with vincristine, lomustine (CCNU) and prednisone. The median follow-up of the entire study population is 36 months (average 43 months; range 12 to 214 months). The 10-year overall (OS) and the progression-free survival (PFS) of the study population were 55.5% (CI 41.4-69.4%) and 34.7% (CI 21.4-47.8%), respectively. Age (< 5 years; > 5 years), sex, site (infratentorial vs. supratentorial), histology (anaplastic/malignant vs. non-anaplastic/non-malignant), type of resection (complete vs. incomplete); use and fields of RT, and of CT employed were entered in a multivariate regression model to test their impact on OS and PFS. On univariate analysis, radical surgery, the use of RT and age more than 5 years at the time of diagnosis achieved statistically significant values for predicting long-term OS and PFS. Histology reached marginal statistical significance but only for PFS. When those variables were entered in a multivariate analysis only radical resection (P = 0.00142 and 0.0001) resulted a significant factor for predicting long-term OS and PFS, while the use of RT reached a marginal statistical significance, but only for PFS (P = 0.05). Children who had the tumour completely resected did significantly better than all the others who had less than a complete resection, with a 10-year OS and PFS for the two groups of patients of 69.8% (CI 53-86.5%) and 57.2% (CI 40.3-75%) and of 32.5% (CI 8.5-57.6%) and 11.1% (0-24.4%), respectively. These findings suggest that, for childhood EPD, radical resection should be pursued as much as reasonably possible. Thus, it seems justified proposing for future trials, patient stratification by entity of surgical resection.

Secreting germ cell tumors of the central nervous system (CNS). First results of the cooperative German/Italian pilot study (CNS sGCT).

BACKGROUND: Secreting germ cell tumors are an invariably fatal subgroup within the malignant pediatric brain tumors. Thus in 1993, an international working group was initiated to establish a cooperative study for diagnostic and treatment of intracranial secreting germ cell tumors of the CNS. To pilot this protocol, since 1994 German and Italian patients are treated in accordance with the established guidelines. METHODS: Regarding to the achieved consensus within the international protocol committee a characteristical diagnostic imaging (CT/MRI scan) of head and spine and a significant increase of tumor markers beta-HCG (> 50 IU/l) and/or AFP (> 25 ng/ml) are defined as sufficient diagnostic criteria. Additionally staging procedures include an initial CSF cytology. Treatment consists of 4 courses PEI: platinum (20 mg/m2 day 1-5), VP16 (100 mg/ m2 day 1-3), and ifosfamide (1.5 g/m2 day 1-5). Surgery of the residual tumor is administered after chemotherapy, if resection is possible, followed by craniospinal irradiation (30 Gy with tumor boost 24 Gy). RESULTS: Until September 96, 19 patients (16 boys and 3 girls) aged 8 to 19 years are registered and have finished their treatment. Seven children are diagnosed by elevated tumor markers. Six of 7 children with stereotactic fine needle biopsy and histology of germinoma have a significant marker increase as a specific characteristic for secreting non-germinomatous germ cell tumors. In 6 patients, the tumor is primarily resected, 2 children are biopsied. In 2 children spinal metastases are diagnosed initially. Tumor marker response is evaluated in 16 children. Thirteen of 16 patients show a clear marker normalization after 2 courses of PEI. One boy with a slight increase of the tumor marker after the 4th course developed an early spinal relapse and died. One girl showed a spinal recurrence during focal radiotherapy. She is still under relapse treatment. A significant decrease of tumor volume after chemotherapy is documented in 10/13 children, who have a definite signal tumor at start of therapy. In 3 children tumor volume does not change despite of marker normalization. Histology of these tumors is teratoma. One of these children died postoperatively because of tumor bleeding. 17/19 patients are alive, 16 of them are in complete remission with a median follow-up of 11 months. CONCLUSION: These results show a further significant increase of event-free survival (EFS 81%). The piloted chemotherapy is proven to be effective and the protocol is now open as an international SIOP CNS GCT study that is started in October 1996.

Multigeneration maternal transmission in Italian families with neural tube defects.

Periconceptional vitamin supplementation with folate prevents about three-quarters of expected cases of neural tube defects (NTDs) in clinical trials. However, vitamin action may be regulated at the level of the gene, and individual susceptibility to environmental agents, including dietary components, also may be under genetic control. We investigated the presence of familial factors in a retrospective case control study of neural tube defects in Genoa, Italy. Cases included all patients treated at a single pediatric neurosurgical service. Controls matched on age and sex came from the same hospital. We found strong evidence for the contribution of genetic factors in this study. There was an excess risk of 14 for the occurrence of NTDs in first-degree relatives compared to controls (P < .0005). There was no difference in sex ratio in any group of relatives, but maternal grandparents of children with a high spinal lesion had 14% fewer off-spring than paternal grandparents (P < .005), possibly because of excess miscarriages. Our study is the first to show complex patterns of inheritance in spina bifida families affecting three generation in one clinical subgroup and preferentially on the mother's side. These results support a role for genomic imprinting and highlight the value of multidisciplinary epidemiologic and clinical studies that include multiple generations. New studies incorporating dietary and genetic approaches will help clarify and extend these findings.

MRI in an unusual case of congenital spinal mesenchymal proliferation.

We report a child aged 2 years presenting with delayed motor development. A thoracolumbar subcutaneous mass was noticed in the first months of life. MRI showed a low conus medullaris, confirmed the presence of the mass and detected a second solid lesion in the intradural space. Surgery confirmed that the two lesions were distinct, as on MRI. The histopathological features were in common with fibrous hamartoma of infancy, giant cell angioblastoma and the "diffuse type" of infantile fibromatosis. The presence of a low conus medullaris associated with a congenital clinical presentation suggested a disontogenetic aetiology.

Medulloblastoma in children: CT and MRI findings.

Our purpose was to determine whether medulloblastoma (MB) shows specific neuroradiological features which may be employed in differential diagnosis from other common posterior cranial fossa tumours in childhood. Preoperative MRI was performed on 20 children with MB, and preoperative CT in 17 of them. All underwent surgery and histopathological diagnosis. There was a constant relationship between high density on CT and low signal on T1-weighted images. Signal behaviour on T2-weighted images and the degree of contrast enhancement were more variable. Most tumours arose in the midline, from the cerebellar vermis, involving the fourth ventricle, but hemisphere and extra-axial neoplasms were also seen. The combination of high density on CT and low signal on T1-weighted images is highly suggestive of MB and may assist preoperative differential diagnosis from other posterior cranial fossa tumours.

Chiari complex in children--neuroradiological diagnosis, neurosurgical treatment and proposal of a new classification (312 cases).

Chiari malformations are a group of anomalies particularly involving the hindbrain and cervical spinal cord. Since these malformations present many common features, we called them "Chiari Complex". After reviewing our 312 patients affected by different types of Chiari malformations we propose the following classification: Chiari I (30 cases): 1) This malformation may be divided in two sub-types: a) classic and b) myelencephalic forms. 2) Only three children were admitted with specific clinical symptoms and they had an occipito-cervical surgical decompression. Chiari II (276 cases): 1) Most of our patients (70%) presented with progressive hydrocephalus and they needed a CSF shunt to be inserted. 2) Seven sub-types of 4th ventricle morphology and size were identified. 3) Only 11 patients underwent a cervical decompression; in 182 children CSF shunting resulted in a good clinical outcome. Chiari III (2 cases): Chiari II signs must be associated with an occipito-cervical cephalocele. In both cases there were other severe associated CNS malformations. Chiari IV (4 cases): We propose this name for patients with myelomeningocele (MMC) and severe cerebellar hypoplasia.

Ependymomas of the posterior cranial fossa: CT and MRI findings.

We studied nine children with posterior cranial fossa ependymomas to identify specific neuroradiological features. Patients were studied preoperatively with CT and MRI; T1-, T2- and proton-density (PD)-weighted images were obtained. All children underwent surgery and a definite histopathological diagnosis was made. All the tumours grew into the fourth ventricle and caused dilatation of its upper part, which resembled a cap. All but one were separated from the vermis by a cleavage plane. In eight cases there was desmoplastic development through the foramina of the fourth ventricle, and five were heterogeneous due to necrosis and cystic change; one had a haemorrhagic area. In most cases the solid portion was isointense with grey matter on T1-weighted images, hyperintense on PD weighting, and isointense on T2-weighted images. On CT the tumour was isodense in six cases and calcification was detected in four. The presence of both desmoplastic development and a tumour/vermis cleavage plane in a posterior cranial fossa tumour isodense on CT is highly suggestive of ependymoma.

Cytogenetics of the tissue involved in neural tube defects.

Cytogenetic techniques were used to study the tissue involved in neural tube defects. Eighteen patients have been evaluated and no specific alterations have been detected. We conclude that, whatever are the mechanisms that lead to neural tube defect, their origins must be searched for at the molecular level.

[Results of early external ventricular diversion in posthemorrhagic ventricular dilatation in the newborn]. / Risultati della derivazione ventricolare esterna precoce nella dilatazione ventricolare postemorragica del neonato.

OBJECTIVE AND DESIGN: The authors report the outcome of early treatment with long-term external ventricular drainage (EVD) of progressive post-hemorrhagic ventricular dilatation (PPHVD), following peri-intraventricular hemorrhage (PIVH) in a population of preterm newborns. SETTING: Neonatal Intensive Care Unit (NICU) of a Children's Hospital. PATIENTS: Twenty-one preterms of 29.6 +/- 2.4 weeks of gestational age, weighing at birth 1443 +/- 445 g, mechanically ventilated, submitted to early EVD because of PPHVD following PIVH of III (n 11) e IV (n 10) grade. METHODS: PPHVD was diagnosed on the basis of US and TC findings. An external liquoral drainage suitable, for its technical characteristics, to be maintained for a long period of time and peculiar anesthesiologic, intra and postoperative treatments were utilized. RESULTS: EVD was placed at 21 +/- 5.8 days of life and maintained for 40 +/- 16 days. In all cases reduction of ventricular size was observed. One case (5%) developed liquoral infection and recovered with antibiotic therapy. No obstruction or dislocation of the ventricular catheter occurred. During EVD 3 patients (14%) died because of respiratory complications. After the normalization of cerebrospinal fluid (CSF), a "permeability test" was performed to assess the canalization of the liquoral system. Seven patients (33.5%) underwent ventriculo-peritoneal shunt (VPS) and 11 (52.5%) became shunt-free. CONCLUSIONS: Our results indicate that long-term use of EVD has a low risk of complications, avoids the need for transcutaneous tips and allows monitoring of CSF characteristics. Furthermore EVD protects the brain from liquoral hypertension, while waiting for a possible recurrence of natural CSF circulation, and is associated with a low number of definitive VPS.

Halo ring supporting the Brown-Roberts-Wells stereotactic frame for fractionated radiotherapy.

The authors describe a new instrumentation for repositioning of the Brown-Roberts-Wells (BRW) stereotaxic system, useful for precise fractionated radiotherapy. A lucite ring is fixed to the patient's skull with four screws. Another ring, partially open, is then firmly connected co-axially to the lower part of the first one with four spacer-bars. The fixture permits an exact repositioning of the B.R.W. stereotaxic system, placing the target point in the linear accelerator isocenter. The preliminary technical results obtained in five children are reported and the fixture performance, advantages, and perspectives are discussed.

Report on a patient with congenital muscular dystrophy, hydrocephalus, Dandy-Walker malformation and leukodystrophy.

We report on a patient affected by congenital muscular dystrophy, severe psychomotor retardation, severe hypotonia, papillar hypoplasia and peculiar NMR pattern of hydrocephalus, Dandy-Walker malformation and leukodystrophy. These findings are intermediate between Walker-Walburg syndrome, Fukuyama disease and Occidental congenital muscular dystrophy. Our case focuses on the wide spectrum of congenital muscle dystrophy associated with central nervous system disease and on the difficulties of genetic counseling in these families.