Mosaic Trisomy 12: Prenatal Diagnosis at Amniocentesis and Molecular Genetic Analysis on Fetal Tissues.

Background: Mosaic trisomy 12 is a genetic condition with few cases diagnosed prenatally and postnatally. Phenotypic variability is wide ranging from normal patients to severe congenital anomalies. Case report: A 35-year-old woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Prenatal ultrasound was negative. Cultured amniocytes revealed a karyotype of 47,XX,+12/46,XX. Parents opted for termination of pregnancy at 22 weeks. Postmortem revealed dysmorphic face; hands with broad thumbs and incomplete transverse palmar creases; partial anomalous pulmonary venous return, intestinal malrotation, and bicornuate uterus. Histologically, no anomalies were identified. Cytogenetic analyses on fetal tissues detected mosaic trisomy 12 in thymus, lung, brain, kidney, placenta, and cord blood. Discussion/Conclusion: We report a new case of mosaic trisomy 12 with non-lethal morphological findings not previously described. Although prenatal ultrasound may be negative, genetic counseling should consider minor abnormalities and widespread presence of trisomic cell lines in various internal organs.

Crystal structure determination of a lifelong biopersistent asbestos fibre using single-crystal synchrotron X-ray micro-diffraction.

The six natural silicates known as asbestos may induce fatal lung diseases via inhalation, with a latency period of decades. The five amphibole asbestos species are assumed to be biopersistent in the lungs, and for this reason they are considered much more toxic than serpentine asbestos (chrysotile). Here, we refined the atomic structure of an amosite amphibole asbestos fibre that had remained in a human lung for ∼40 years, in order to verify the stability in vivo. The subject was originally exposed to a blend of chrysotile, amosite and crocidolite, which remained in his parietal pleura for ∼40 years. We found a few relicts of chrysotile fibres that were amorphous and magnesium depleted. Amphibole fibres that were recovered were undamaged and suitable for synchrotron X-ray micro-diffraction experiments. Our crystal structure refinement from a recovered amosite fibre demonstrates that the original atomic distribution in the crystal is intact and, consequently, that the atomic structure of amphibole asbestos fibres remains stable in the lungs for a lifetime; during which time they can cause chronic inflammation and other adverse effects that are responsible for carcinogenesis. The amosite fibres are not iron depleted proving that the iron pool for the formation of the asbestos bodies is biological (haemoglobin/plasma derived) and that it does not come from the asbestos fibres themselves.

TRAP Sequence in Monochorionic/Monoamniotic (MC/MA) Discordant Twins: Two Cases Treated with Fetoscopic Laser Surgery.

INTRODUCTION: Ablation of the acardiac twin umbilical cord in the TRAP protects the normal donor twin. MATERIALS AND METHODS: Two case descriptions, one of interstitial laser photocoagulation and one of laser umbilical cord occlusion (L-UCO) of the acardiac twin in monochorionic monoamniotic pregnancies are reported. RESULTS: L-UCO in two pregnancies with TRAP syndrome in the second trimester resulted in intrauterine fetal death in both cases after 1 month. Case 1 had no detectable cause of fetal death. Case 2 had rupture of the amniotic sac causing anhydramnios and acute chorioamnionitis. A groove on the umbilical cord of the normal twin indicated a cord stricture due to cord entanglement. CONCLUSION: Our experience confirms that the best timing and optimal treatment of MC/MA twins complicated by TRAP sequence still remains a controversial clinical issue. Cord entanglement may continue be a potential clinical risk factor for adverse perinatal outcome even after ablation therapy.

Antenatal Diagnosis of a Large Immature Abdominal Wall Teratoma by 2D-3D Ultrasound Using HDlive and Magnetic Resonance Imaging.

We describe the first case of prenatally detected teratoma of the fetal abdomen wall using ultrasound and fetal magnetic resonance imaging (MRI). A heterogeneous mass, partly solid and cystic, originating from the anterior abdominal wall of the fetus close to an omphalocele sac was detected by means of 2D/3D ultrasound and MRI. Amniodrainage was performed and due to sign of impending fetal risk, an emergency Cesarean section was performed. A bulky, crumbly and bleeding tumoral mass was confirmed at delivery. Ligation of the supplying artery to the tumor was complicated by uncontrollable hemorrhage and early neonatal death. Pathology identified the tumor as an immature teratoma of the anterior fetal abdominal wall. 2D/3D ultrasound, especially using HDlive application and MRI demonstrated accurate detection and characterization of this congenital tumor.

Sequential analysis of the normal fetal fissures with three-dimensional ultrasound: a longitudinal study.

OBJECTIVE: To perform a sequential analysis of the main cortical fissures in normal fetuses using 3D ultrasound. METHODS: A cohort of patients with uncomplicated singleton pregnancies underwent three consecutive transabdominal scans at 19-21, 26-28 and 30-34 weeks. Volumes of the fetal head were acquired and searched in the multiplanar mode for the following cortical fissures: sylvian, parieto-occipital, calcarine, hippocampus and cingulate. A qualitative analysis of these sulci was performed in each volume by an experienced operator (A) and a trainee (B). By placing the dot on the sulcus in one plane, it was evaluated whether it was visible also in other planes. RESULTS: Fifty patients were included in the study. At 19-21 weeks, the sylvian and parieto-occipital sulci were visualized on at least one plane by both operators in all cases. At 26-28 weeks, all fissures were visualized by both operators on at least one plane, with no significant difference between the performances of the two operators. At 30-34 weeks, a mild overall decline in the accuracy of identification of all the cerebral fissures was observed. CONCLUSIONS: 3D multiplanar mode allows a systematic evaluation of the cortical fissures in normal fetuses since midtrimester.

The distribution and frequency of pulmonary neuroendocrine cells in Down syndrome fetal lungs.

The pulmonary neuroendocrine cells (PNEC) are located in the epithelial lining of the airways and consist of solitary neuroendocrine cells (NEC) and NEC clusters, the neuroepithelial bodies (NEB). During fetal life, PNEC are the first to differentiate within the primitive airway epithelium, and bombesin expression favors branching of the respiratory tree. We investigated PNEC in Down syndrome (DS), where the lungs often show enlarged and reduced number of alveoli. Immunohistochemistry for bombesin and synaptophysin, PNEC markers, was evaluated in fetal lungs from 15 cases of DS and 11 age-matched controls from the 17th to 23rd week of gestation. Morphometric analysis assessed PNEC in the mucosal lining of each lung, expressed as number/mm. Nonparametric Mann-Whitney U test showed no statistical difference in frequency of PNEC in DS and controls. Our findings suggest that, at least in late second trimester, the distribution and frequency of PNEC in DS fetuses is not altered.

The role of diagnostic imaging and liver biopsy in the diagnosis of focal nodular hyperplasia in children.

BACKGROUND & AIMS: Focal nodular hyperplasia (FNH), a benign liver tumour, has a characteristic appearance on diagnostic imaging (DI) and histology. The role of liver biopsy in children for the diagnosis of FNH is unclear. This study investigates the diagnostic accuracy of DI for FNH in children without comorbidities, compared to liver biopsy. METHODS: A total of 304 consecutive patients (age <18 years) with a biopsied liver mass were retrospectively ascertained (1990-2010). Individuals with a history of malignancy, liver disease or syndromes with increased malignancy risk were excluded. DI and biopsy data were reviewed. RESULTS: After excluding 205 cases, 99 liver masses were studied. Based on histology, the most common diagnosis was hepatoblastoma (46/99, 44%) followed by FNH (23/99, 23%). The mean age at FNH diagnosis was 11.1 ± 5.2 years, with female preponderance (78%), and a median follow-up of 1.35 years (interquartile range 0.54, 4.20 years). 19/23 biopsy-proven FNH met standard criteria for FNH on DI. In 4/23 cases of biopsy-proven FNH, imaging did not suggest FNH. Two false positive cases included adenoma and fibrolamellar hepatocellular carcinoma. On review of original reports, DI had 82.6% sensitivity and 97.4% specificity for the diagnosis of FNH. On blind review, the sensitivity of DI for FNH diagnosis was 81.3% for MRI (13/16), and 53.3% for CT (8/15). CONCLUSIONS: In this cohort of children with liver masses and no comorbidities, a diagnosis of FNH by imaging was highly specific, and MRI was the most sensitive study for its diagnosis. Liver biopsy may be deferred in selected children if the DI, particularly MRI, is indicative of FNH.

Normal morphometry of fetal posterior fossa at midtrimester: brainstem-tentorium angle and brainstem-vermis angle.

OBJECTIVE: To standardize the evaluation of normal tentorium insertion and normal rotation of the cerebellar vermis over the brainstem, using two novel measurements: the brainstem-tentorium angle (BT angle) and the brainstem-vermis angle (BV angle). We also aimed to test the reproducibility of these measurements. METHODS: Prospective observational study including normal fetuses at routine anomaly scan with confirmed normal follow-up. Three-dimensional volumes of the fetal head were acquired starting from standard trans-cerebellar views. In the sagittal plane, obtained by multiplanar reconstruction, the angle between the brainstem and the tentorium insertion in the fetal skull, and between the brainstem and the lower edge of the vermis were measured twice by two independent operators. Intraobserver and interobserver variations were calculated. RESULTS: Eighty cases were included. The estimated BT and BV angles lie in a wide interval among normal midtrimester fetuses with a median value (min-max) of 25.65 (20.13-47.39) and 9.29 (3.87-19.36) respectively. Intraobserver and interobserver variation were good for both measurements. CONCLUSION: The BT and BV angle may be of help in assessing the fetal posterior fossa at midgestation and gives a standardized and reproducible measurement of normal tentorium insertion and normal rotation of the cerebellar vermis over the brainstem.

Widespread proliferation impairment and hypocellularity in the cerebellum of fetuses with down syndrome.

Evidence in mouse models for Down syndrome (DS) and human fetuses with DS clearly shows severe neurogenesis impairment in various telencephalic regions, suggesting that this defect may underlie the cognitive abnormalities of DS. As cerebellar hypotrophy and motor disturbances are part of the clinical features of DS, the goal of our study was to establish whether these defects may be related to neurogenesis impairment during cerebellar development. We found that in fetuses with DS (17-21 weeks of gestation) the cerebellum had an immature pattern, a reduced volume and notably fewer cells (-25%/-50%) in all cerebellar layers. Immunohistochemistry for Ki-67, a marker of cycling cells, showed impaired proliferation (-17%/-50%) of precursors from both cerebellar neurogenic regions (external granular layer and ventricular zone). No differences in apoptotic cell death were found in DS vs. control fetuses. The current study provides novel evidence that in the cerebellum of DS fetuses there is a generalized hypocellularity and that this defect is due to proliferation impairment, rather than to an increased cell death. The reduced proliferation potency found in the DS fetal cerebellum, in conjunction with previous evidence, strengthens the idea that the trisomic brain is characterized by widespread neurogenesis disruption.

Fetal cerebral periventricular halo at midgestation: an ultrasound finding suggestive of fetal cytomegalovirus infection.

OBJECTIVE: The objective of the study was to identify a cerebral ultrasound finding indicative of fetal cytomegalovirus (CMV) infection at midgestation. STUDY DESIGN: All fetuses of 218 patients with primary CMV infection underwent prospective transvaginal neurosonographic examination at 20-22 weeks' gestation. RESULTS: Transvaginal sonography identified a periventricular echogenic halo with well-defined borders in 6 infected fetuses at a mean gestational age of 20.5 weeks. Transabdominal axial views of the fetal head were normal in all cases. All patients opted for termination of pregnancy. Autopsy in 2 fetuses showed changes compatible with subacute white matter injury resembling telencephalic leukomalacia. CONCLUSION: A fetal cerebral periventricular halo disclosed by transvaginal sonography at midgestation in pregnant patients with recent CMV infection is suggestive of fetal infection and may be associated with white matter lesions.

Neurogenesis impairment and increased cell death reduce total neuron number in the hippocampal region of fetuses with Down syndrome.

We previously obtained evidence for reduced cell proliferation in the dentate gyrus (DG) of fetuses with Down syndrome (DS), suggesting that the hippocampal hypoplasia seen in adulthood may be caused by defective early neuron production. The goal of this study was to establish whether DS fetuses (17-21 weeks of gestation) exhibit reduction in total cell number in the DG, hippocampus and parahippocampal gyrus (PHG). Volumes of the cellular layers and cell number were estimated with Cavalieri's principle and the optical fractionator method, respectively. We found that in DS fetuses all investigated structures had a reduced volume and cell number. Analysis of cell phenotype showed that DS fetuses had a higher percentage of cells with astrocytic phenotype but a smaller percentage of cells with neuronal phenotype. Immunohistochemistry for Ki-67, a marker of cycling cells, showed that DS fetuses had less proliferating cells in the germinal zones of the hippocampus and PHG. We additionally found that in the hippocampal region of DS fetuses there was a higher incidence of apoptotic cell death. Results show reduced neuron number in the DS hippocampal region and suggest that this defect is caused by disruption of neurogenesis and apoptosis, two fundamental processes underlying brain building.

Cell cycle alteration and decreased cell proliferation in the hippocampal dentate gyrus and in the neocortical germinal matrix of fetuses with Down syndrome and in Ts65Dn mice.

Down syndrome (DS), the leading genetic cause of mental retardation, is characterized by reduced number of cortical neurons and brain size. The occurrence of these defects starting from early life stages points at altered developmental neurogenesis as their major determinant. The goal of our study was to obtain comparative evidence for impaired neurogenesis in the hippocampal dentate gyrus (DG) of DS fetuses and Ts65Dn mice, an animal model for DS. Cell proliferation in human fetuses was evaluated with Ki-67 (a marker of cells in S + G(2) + M phases of cell cycle) and cyclin A (a marker of cells in S phase) immunohistochemistry. We found that in the DG of DS fetuses the number of proliferating cells was notably reduced when compared with controls. A similar reduction was observed in the germinal matrix of the lateral ventricle. In both structures, DS fetuses showed a reduced ratio between cyclin A- and Ki-67-positive cells when compared with controls, indicating that they had a reduced number of cycling cells in S phase. In the DG of P2 Ts65Dn mice cell proliferation, assessed 2 h after an injection of bromodeoxyuridine (BrdU), was notably reduced, similarly to DS fetuses. After 28 days, Ts65Dn mice had still less BrdU-positive cells than controls. Phenotypic analysis of the surviving cells showed that Ts65Dn mice had a percent number of cells with astrocytic phenotype larger than controls. Using phospho-histone H3 immunohistochemistry we found that both DS fetuses and P2 Ts65Dn mice had a higher number of proliferating cells in G(2) and a smaller number of cells in M phase of cell cycle. Results provide novel evidence for proliferation impairment in the hippocampal DG of the DS fetal brain, comparable to that of the P2 mouse model, and suggest that cell cycle alterations may be critical determinants of the reduced proliferation potency.