Carla Ramalho

Search for hemodynamic compromise at 11–14 weeks in monochorionic twin pregnancy: Is abnormal flow in the ductus venosus predictive of twin–twin transfusion syndrome?

Background and objectives. Twin–twin transfusion syndrome is a devastating complication of monochorionic twin pregnancies. The presence of increased nuchal translucency thickness (NT) in one of the monochorionic twins has been associated with an increased risk of developing this syndrome. One of the most plausible mechanisms for increased nuchal translucency is heart failure, indirectly manifested by abnormal blood flow in the ductus venosus. We aimed to clarify the pathophysiology of increased NT found more frequently in monochorionic twins prone to develop twin–twin transfusion syndrome. Design. We present 50 cases of monochorionic twin pregnancies in which nuchal translucency thickness was measured and ductus venosus blood flow evaluation was performed at 11–14 weeks of gestation. Results. Whenever the fetuses of a twin pregnancy were found to have discrepant nuchal translucency thickness measurements and abnormal flow in the ductus venosus was found in the fetus with increased nuchal translucency thickness, twin–twin transfusion syndrome eventually developed. Progression to twin-to-twin transfusion syndrome was not observed in the twins displaying no intertwin difference in nuchal translucency thickness measurements and it was not observed in those with discrepant nuchal translucency thickness but normal flow in the ductus venosus of both fetuses. In the two cases which developed twin-to-twin transfusion syndrome, fetoscopic laser coagulation of the vascular anastomoses was successfully carried out at 18 weeks and normalization of the venous return was recorded. Conclusions. Both increased nuchal translucency and abnormal flow in the ductus venosus in monochorionic twins may be early manifestations of haemodynamic imbalance between donor and recipient. The combined evaluation of both parameters in monochorionic twin pregnancies may constitute an effective method for identifying those at risk of developing twin-to-twin transfusion syndrome.

Gene expression pattern of IGF2, PHLDA2, PEG10 and CDKN1C imprinted genes in spontaneous miscarriages or fetal deaths.

Genomic imprinting is defined as an epigenetic modification that leads to parent-of-origin specific monoallelic expression. Some current research on the fetal control growth has been focused on the study of genes that display imprinted expression in utero. Four imprinted genes, two paternally expressed (IGF2 and PEG10) and two maternally expressed (PHLDA2 and CDKN1C), are well known to play a role in fetal growth and placental development. Pregnancy loss in the general reproductive population is a very common occurrence and other genetic causes beyond chromosomal abnormalities could be involved in spontaneous miscarriages or fetal deaths, such as alteration of expression in imprinted genes particularly those related to fetal or placental growth. Quantitative Real Time PCR was performed to evaluate gene expressions patterns of the four mentioned genes in spontaneous miscarriages or fetal deaths from 38 women. Expression levels of PHLDA2 gene were upregulated in the first trimester pregnancy cases and all four imprinted genes studied were upregulated in the second trimester of pregnancy cases comparing with controls. In third trimester PEG10 was downregulated in fetal samples group. This is the first study presenting data from human imprinted genes expression in spontaneous miscarriages or fetal deaths cases from the three trimesters of pregnancy.

An efficient protocol for the detection of chromosomal abnormalities in spontaneous miscarriages or foetal deaths

OBJECTIVE Characterization of chromosomal abnormalities in 232 spontaneous miscarriages or foetal deaths using both classical and molecular cytogenetics. STUDY DESIGN Chromosomal abnormalities are responsible for 40-50% of all early pregnancy losses. Conventional cytogenetics is associated with 10-40% of culture failure. Comparative genomic hybridization (CGH) is a DNA-based technique that screens chromosome imbalances in the whole genome and may overcome this problem, although additional methods are required to distinguish between different ploidies, mosaicisms and maternal cell contamination. For a full characterization of chromosomal aberrations in 232 spontaneous miscarriages or foetal deaths we applied a sequential protocol that uses conventional cytogenetics, plus CGH and touch fluorescence in situ hybridization (Touch FISH). RESULTS Successful karyotyping was obtained in 173/232 (74.6%) of the cases, 66/173 (38.2%) of which had an abnormal chromosomal complement. CGH and Touch FISH analyses revealed another 19 abnormal cases in the 63 failures of culture. Overall there were 85/233 (36.6%) cases with an abnormal chromosomal complement, with examples from all three trimesters. Comparing cases, with or without chromosomal abnormalities, no statistical differences were found between women with one or recurrent miscarriages. On the contrary, significant differences were found comparing mean maternal ages or mean gestational ages, in cases with or without chromosomes abnormalities. CONCLUSION Adopting this sequential protocol, chromosomal complement information was available even in cases with culture failure.

Evolving Indications for the EXIT Procedure: The Usefulness of Combining Ultrasound and Fetal MRI

The EXIT procedure (EX utero Intrapartum Treatment) encompasses a multidisciplinary approach to situations in which airway obstruction is anticipated. Uteroplacental circulation is maintained to avoid neonatal hypoxemia while intubation is attempted. Not only is it useful in congenital diaphragmatic hernia with intrauterine tracheal occlusion, but new indications have been proposed. We present two cases in which EXIT procedure was adopted (huge cervical mass with tracheal compression and a highly vascularized cephalocervical mass) for the same purpose on different grounds. Our two cases stress once more the importance of combining fetal ultrasound and magnetic resonance imaging in the characterization of cervical masses and its usefulness in programming the procedure with a multidisciplinary team.

Relevance of genomic imprinting in intrauterine human growth expression of CDKN1C, H19, IGF2, KCNQ1 and PHLDA2 imprinted genes

PurposeTo study the relationship of imprinted gene expression (CDKN1C, H19, IGF2, KCNQ1 and PHLDA2) with human fetal growth.MethodsRNA was extracted from fetuses with intrauterine growth restriction (IUGR) and from the controls without growth restriction. The gene expression pattern of CDKN1C, H19, IGF2, KCNQ1 and PHLDA2 genes was evaluated using RT-PCR. MS-MLPA was also performed to assess the IC1 and IC2 DNA methylation status on chromosome 11p15.5.ResultsThe samples were divided according to their tissue type in placental or fetal tissue. Within each group, IUGR cases and controls were compared. In the IUGR cases, in both fetal and placental tissue groups IGF2 was observed to be down regulated. In another approach, the samples were divided in IUGR and control groups and for each of them placental and fetal tissue was compared. Within the IUGR group up regulation of CDKN1C, KCNQ1, and PHLDA2 was determined in placental samples. IUGR group presented a statistically lower methylation status in both IC1 and in IC2. Regarding differences between fetal and placental samples within this group, methylation status of placental samples was statistically significant down regulated in the imprinting center 1 (IC1).ConclusionsGenomic imprinting is a phenomenon that plays an important role in fetal and placental development. This study emphasizes the importance of imprinted genes during pregnancy. Differences between tissues could reflect different mechanisms, either compensatory or adverse, that should be investigated in more detail.

Aneuploidies detection in miscarriages and fetal deaths using multiplex ligation-dependent probe amplification: an alternative for speeding up results?

OBJECTIVE The aim of this prospective study was to apply the MLPA technique to products of miscarriages and fetal deaths in order to detect the more frequent chromosome aneuploidies and compare the results to conventional karyotyping. STUDY DESIGN Multiplex ligation-dependent probe amplification (MLPA) is a relatively new molecular technique for targeted detection of common chromosomal aneuploidies, namely trisomy 13, 18, 21 and sex chromosomal abnormalities. The reliability and high accuracy of this technique constitute an alternative for rapid results in large scale testing. In this study, a total of 489 DNA samples from fetal tissue were used for aneuploidy detection of chromosomes 13, 18, 21, X and Y using a commercial MLPA kit (SALSA P095) and were simultaneously subjected to conventional karyotyping. RESULTS MLPA was the only result available in 33% of the cases. A cytogenetic result was obtained in only 328/489 samples. MLPA detected 7.8% of chromosome aneuploidies. Among the total samples karyotyped, MLPA failed to detect some aneuploidies and the false-negative rate was 0.82%. As expected, ploidy changes and reciprocal translocations were not detected by this technique, but MLPA gave a conclusive result even in cases of mosaicism. CONCLUSION The present data confirm that MLPA is a rapid, simple and reliable method for detection of chromosome 13, 18, 21, X and Y abnormalities in fetal tissue.

Revisiting Amniotic Band Sequence: A Wide Spectrum of Manifestations

Objective: To describe the spectrum of clinical deformities related to amniotic band sequence (ABS), ranging from mild to severe. Methods: Retrospective evaluation of 9 cases of ABS managed during a 4-year period (February 2006 to April 2010) in a tertiary hospital. Results: The median gestational age at prenatal diagnosis was 15 weeks (range 11-26). Only 2 patients had clinical prenatal evidence of amnion rupture. In the other 5 cases the diagnosis of ABS was established prenatally based on fetal structural abnormalities. These abnormalities included: (1) upper limb defects: syndactyly, amputation at the level of phalanges or first metacarpal or forearm; (2) inferior extremities defects: tallus equinovarus and flexed knee, and constriction ring; (3) umbilical cord strangulation, and (4) acrania. Conclusion: ABS is a polymorphous syndrome and recognizing its various manifestations can be of help in prenatal identification.

Complete mole in a dichorionic twin pregnancy after intracytoplasmic sperm injection

A dichorionic twin pregnancy with complete hydatidiform mole and coexistent fetus is a rare and challenging situation, whose pathogenesis has not been yet fully understood. We present a case of a 39-year-old woman who underwent intracytoplasmic sperm injection with two embryos transfer. The 12-week gestation ultrasound examination revealed normal fetus and placenta with features of hydatidiform mole, leading to pregnancy termination. Autopsy and histological examinations diagnosed a complete mole coexisting with a normal fetus, and the genetic analysis showed a diploid fetus with biparental genome and molar tissue with paternal diploidy. This case highlighted that complete molar pregnancies may still occur even though pregnancy is achieved after intracytoplasmic sperm injection. A review of the literature was performed by collecting data from the few similar reported cases and by commenting on the pathogenesis of this rare condition.

Revisiting Acrania: Same Phenotype, Different Aetiologies

Objective: To evaluate the contribution of prenatal and postmortem examinations in establishing the aetiology of acrania. Methods: Retrospective evaluation of 14 cases of acrania managed through elective termination of pregnancy. Results: The median maternal age was 30 years (range 18–40) and median gestational age at diagnosis was 13 weeks (range 12–15). One mother had epilepsy and was taking anticonvulsants and another had uncontrolled type II diabetes mellitus. Only 3 women were using folic acid at conception. Chromosomal abnormalities were detected in 3 of 8 cases analyzed. Unilateral anopthalmia, cervical rachischisis, midline facial and limb defects coexisted with acrania in 4 cases. Acrania with craniofacial dysmorphism and asymmetrical finger amputation were observed in a case of amniotic band syndrome. A previous history of anencephaly was documented in 1 case. Conclusion: Acrania is a characteristic phenotypic expression of a variety of different aetiologies. Investigation with cytogenetic studies and postmortem are essential to provide a definitive answer. This will provide a better understanding of the underlying aetiology and help establish the recurrence risk for future pregnancies.

Phenotypic Expression in the First Case of Complete Trisomy 12: Combination of Prenatal Ultrasound and Necropsic Examination

The authors report the first case of a complete trisomy 12 detected antenatally at 16 weeks of gestation. The ultrasonographic features (craniofacial abnormalities) correlated well with postmortem findings. The absence of the hypophysis gland, olfactory pathways and both adrenal glands, as well as developmental anomalies of the central nervous system, were additional findings at autopsy. The recognition of complete trisomy 12 phenotype can be helpful in the pre- and postnatal diagnosis of future similar cases and parental counseling.