Fetale Lageanomalien und Heterotaxien

Heterotaxy Syndrome with Increased Nuchal Translucency and Normal Karyotype Associated with Complex Systemic Venous Return. Ultrasound Diagnosis with Autopsy Correlation

Background: Prenatal ultrasound (US) detection of heterotaxy syndrome can be challenging, especially in identifying cardiovascular and associated anomalies. We present a new case of heterotaxy syndrome with anomalous systemic venous return (ASVR) fully displayed at autopsy. Case report: Left heterotaxy syndrome was diagnosed in a 19 weeks' of gestation fetus with right-sided stomach. The heart showed both ventricles with left morphology, a large ventricular septal defect, persistent left superior vena cava draining into the coronary sinus, ASVR with interrupted inferior vena cava (IVC) and azygous continuation. Autopsy dissection further identified the azygous draining into the left lower pulmonary vein (LLPV). Prenatal a-CGH on villous sampling showed 22q13.1 microduplication inherited from the father, not contributory to the phenotype. Conclusion/discussion: Heterotaxy syndrome requires US accuracy for anomaly identification, as they allow legal termination of pregnancy. Our case is unusual as IVC drained into the azygous vein and then into the LLPV.

Characteristics and outcomes of fetuses with laterality defects are the current outcomes better? A single center study

Objective: To analyze the more recent outcomes of fetuses with different laterality defects.Material and methods: Out of 1508 fetuses with congenital heart disease (CHD) diagnosed by echocardiography between January 1995 and December 2015, 94 (6.3%) presented abnormal visceroatrial situs: 42 till December 2002 (group 1, analyzed retrospectively) and 52 since then until December 2015 (group 2, analyzed prospectively). Twenty-one had left isomerism (Lisom), 22 right isomerism (Risom), 16 situs inversus- dextrocardia (SVI-dx), 5 situs inversus- levocardia (SVI-levo), and 30 situs solitus-dextrocardia (SSol-dx).Results: Seventy-six cases (81%) had CHD, more frequently complex atrioventricular defect. Eighteen cases showed normal heart: half of subgroups SVI-dx and SVI-levo, a third of SSol-dx. Postoperative mortality in continuing pregnancy in group 2 was 43.7 versus 40% in group 1, lower in SVs-dx (0 versus 50%) and Lisom (33.3 versus 66.7%), worse in Risom (71.4 versus 25%). Total mortality in group 2 was 48.3 versus 55% in group 1, better in Ssol-dx (37.5 versus 50%) and in Lisom (27.4 versus 71.4%). In isolated forms all but one case are alive.Conclusions: Our fetal cases presented a relevant mortality in both periods. The outcomes were slightly better in a more recent era in SSol and Lisom.What is known about this topic?Out of laterality defects, the heterotaxies (i.e. left and right isomerism) are known to be associated to a relevant mortality in fetal and neonatal cases.Heterotaxies have a variable position of the heart, but some authors evaluated only those with dextrocardia in their studies on different laterality defects.Controversial data are presented in the literature for the outcomes of fetuses with laterality defects. Many large studies analyzed the data of a very long time period in which it is opinable to compare the results of the treatment, because of a recent improved management and surgical techniques.What does this study add?Our study presents an experience of a single center with cases of different types of laterality defects observed during a routine fetal echocardiography, not only heterotaxies.The knowledge of different laterality defects and of their characteristics (association with cardiac and extracardiac anomalies or with normal heart) is useful for the prenatal counseling.We compare the postoperative and total mortality in more recent period (since 2003) with respect to the previous era (1995-2002).

Duplication and deletion of CFC1 associated with heterotaxy syndrome

Heterotaxy syndrome, which causes significant morbidity and mortality, is a class of congenital disorders, in which normal left-right asymmetry cannot be properly established. To explore the role of copy number variants (CNVs) in the occurrence of heterotaxy syndrome, we recruited 93 heterotaxy patients and studied 12 of them by the Affymetrix Genome-Wide Human SNP 6.0 Array. The results were confirmed in the remaining 81 patients and 500 healthy children by quantitative real-time polymerase chain reaction (qPCR). The analysis of the SNP6.0 array showed a duplication of chromosome 2q21.1, which was verified by qPCR. The result of qPCR in the other 81 patients showed that 8/81 patients had the CNVs of 2q21.1 and the only overlapping gene in these patients is CFC1. However, in the 500 healthy children, only one carried the duplication of CFC1 (p=3.5×10(-7)). The duplication and deletion of CFC1 may play key roles in the occurrence of heterotaxy syndrome. Moreover, the transposed great arteries, double outlet right ventricle, single atrium, and single ventricle may share a common genetic etiology with the heterotaxy syndrome.

Perinatal outcome in fetuses with heterotaxy syndrome and atrioventricular block or bradycardia

Congenital atrioventricular (AV) block is commonly associated with heterotaxy syndrome; together they have reportedly low survival rates (10-25%). However, information about perinatal outcome and predictors of non-survival after prenatal diagnosis of this association is scarce. Therefore, we studied fetuses with heterotaxy syndrome and bradycardia or AV-block diagnosed between 1995 and 2011, and analyzed pre and post-natal variables. The primary outcome was death and the secondary outcome was pacemaker placement. Of the 154 fetuses with heterotaxy syndrome, 91 had polysplenia syndrome, 22/91(24%) with bradycardia or AV-block. Thirteen (59%) patients had sinus bradycardia at diagnosis, 8 (36%) complete AV block, and 1 (5%) second-degree AV-block. Three patients elected for termination of pregnancy (3/22, 14%), 4 had spontaneous fetal demise (4/22, 18%), and 15 (15/22, 68%) were live-born. Of the fetuses with bradycardia/AV-block, 30% presented with hydrops, 20% had ventricular rates <55 beats/min, and 10% had cardiac dysfunction. Excluding termination of pregnancy, 15/19 fetuses (79%) survived to birth. Among the 15 live-born patients, 4 had bradycardia and 11 had AV-block. A further 3 patients died in infancy, all with AV-block who required pacemakers in the neonatal period. Thus, the 1-year survival rate, excluding termination of pregnancy, was 63% (12/19). Of the remaining 12 patients, 9 required pacemaker. Predictors of perinatal death included hydrops (p < 0.0001), ventricular dysfunction (p = 0.002), prematurity (p = 0.04), and low ventricular rates (p = 0.04). In conclusion, we found a higher survival rate (63%) than previously published in patients with heterotaxy syndrome and AV block or bradycardia diagnosed prenatally. Hydrops, cardiac dysfunction, prematurity and low ventricular rates were predictors of death.

Follow your gut: relaying information from the site of left-right symmetry breaking in the mouse

A central unresolved question in the molecular cascade that drives establishment of left-right (LR) asymmetry in vertebrates are the mechanisms deployed to relay information between the midline site of symmetry-breaking and the tissues which will execute a program of asymmetric morphogenesis. The cells located between these two distant locations must provide the medium for signal relay. Of these, the gut endoderm is an attractive candidate tissue for signal transmission since it comprises the epithelium that lies between the node, where asymmetry originates, and the lateral plate, where asymmetry can first be detected. Here, focusing on the mouse as a model, we review our current understanding and entertain open questions concerning the relay of LR information from its origin.