U. Herberg

Molecular diagnosis in mitochondrial complex I deficiency using exome sequencing

Background Next generation sequencing has become the core technology for gene discovery in rare inherited disorders. However, the interpretation of the numerous sequence variants identified remains challenging. We assessed the application of exome sequencing for diagnostics in complex I deficiency, a disease with vast genetic heterogeneity. Methods Ten unrelated individuals with complex I deficiency were selected for exome sequencing and sequential bioinformatic filtering. Cellular rescue experiments were performed to verify pathogenicity of novel disease alleles. Results The first filter criterion was ‘Presence of known pathogenic complex I deficiency variants’. This revealed homozygous mutations in NDUFS3 and ACAD9 in two individuals. A second criterion was ‘Presence of two novel potentially pathogenic variants in a structural gene of complex I’, which discovered rare variants in NDUFS8 in two unrelated individuals and in NDUFB3 in a third. Expression of wild-type cDNA in mutant cell lines rescued complex I activity and assembly, thus providing a functional validation of their pathogenicity. Using the third criterion ‘Presence of two potentially pathogenic variants in a gene encoding a mitochondrial protein’, loss-of-function mutations in MTFMT were discovered in two patients. In three patients the molecular genetic correlate remained unclear and follow-up analysis is ongoing. Conclusion Appropriate in silico filtering of exome sequencing data, coupled with functional validation of new disease alleles, is effective in rapidly identifying disease-causative variants in known and new complex I associated disease genes.

Long term cardiac follow up of severe twin to twin transfusion syndrome after intrauterine laser coagulation

Objective: To assess long term changes in cardiac morphology and function in survivors of severe twin to twin transfusion syndrome (TTTS) after intrauterine laser coagulation of placental anastomoses. Design: Prospective follow up of fetuses with severe TTTS treated by laser coagulation of intrauterine placental anastomoses. Fetal echocardiography and Doppler studies of feto-placental haemodynamic function were performed at the time of laser coagulation (median gestational age of 21.7 weeks). Postnatal cardiac follow up included a detailed echocardiographic study of systolic and diastolic cardiac function at a median age of 21.1 months. Setting: Paediatric cardiology unit. Patients: 89 survivors from 73 consecutive pregnancies with severe TTTS. Results: Before laser treatment, 28 of 51 (54.9%) recipient twins had typical signs of cardiac dysfunction due to volume overload and 9 of 38 (23.7%) donors had absent or reversed end diastolic flow in the umbilical artery. Echocardiography was normal in 87.6% of the survivors (34 of 38 donors, 44 of 51 recipients). The prevalence of congenital heart disease and particularly of pulmonary stenosis, which was recorded only in recipients, was increased in comparison with the general population (congenital heart disease, 10 of 89 (11.2%) v 0.3%; pulmonary stenosis, 4 of 51 (7.8%) v 0.03%). Findings before laser treatment were not correlated with the development of structural heart disease. Conclusions: Despite the high rate and severity of prenatal cardiac overload in recipients, the majority of cases of TTTS are normalised after laser treatment. However, given the increased prevalence of congenital heart disease and in particular pulmonary stenosis, intrauterine and postnatal follow up is warranted.

Right aortic arch detected in fetal life

To evaluate the prenatal distribution, associated conditions and outcome of the different types of right aortic arch (RAA) detected in fetal life.

Dynamic free-hand three-dimensional fetal echocardiography gated by cardiotocography.

To evaluate the clinical feasibility of conventional cardiotocography (CTG) as a cardiac cycle triggering signal for three‐dimensional (3D) fetal echocardiography.

Hybrid procedures can reduce the risk of congenital cardiovascular surgery

BACKGROUND Minimally invasive operations and percutaneous interventions are well-accepted options in the treatment of congenital heart defects. However, percutaneous interventions may be associated with an increased risk due to limited vascular access or a very tortuous catheter course. In these cases, combining operative and interventional approaches with direct puncture of the heart or the great vessels may facilitate implantation of even large devices. Furthermore, in some situations, cardiopulmonary bypass or circulatory arrest can be omitted when doing a hybrid procedure. PATIENTS Between January 2000 and April 2007 17 patients were operated in a hybrid fashion. Age ranged from 14 days to 45 years. Operative procedures consisted of implantation of an atrial septal defect occluder via direct puncture of the right atrium (n=4), closure of a ventricular septal defect via direct puncture of the right ventricle (n=1), implantation of isthmus stents via the ascending aorta (n=5), redilation of an isthmus stent (n=1), redilation of a ductal stent (n=1), angioplasty of a pulmonary artery stenosis (n=1), interventional occlusion of an intrahepatic porto-caval shunt (n=1), stent implantation into the right pulmonary artery (n=1) and into the right ventricular outflow tract (n=1) under direct vision as well as atrioseptoplasty combined with a bilateral pulmonary artery banding in one newborn with a single ventricle and very low birth weight (n=1). RESULTS The planned intervention could be performed in all cases under the assistance of intraoperative fluoroscopy, transesophageal or epicardial echocardiography, or under direct vision. In all cases, the primary hemodynamic objectives were achieved. CONCLUSION In selected patients, the combination of a surgical procedure and a percutaneous intervention may help to reduce both operative and interventional risks. This concept may enable new treatment options, especially in patients with complex congenital heart defects or complex vascular situations.

Three- and four-dimensional freehand fetal echocardiography: a feasibility study using a hand-held Doppler probe for cardiac gating

To evaluate the clinical feasibility of the signal from a hand‐held Doppler probe as a real‐time tracking signal for dynamic three‐dimensional (3D) (so‐called four‐dimensional (4D)) fetal echocardiography in a random patient cohort.

Natural history of 107 cases of fetal aortic stenosis from a European multicenter retrospective study

Fetal aortic valvuloplasty (FV) aims to prevent fetal aortic valve stenosis progressing into hypoplastic left heart syndrome (HLHS), which results in postnatal univentricular (UV) circulation. Despite increasing numbers of FVs performed worldwide, the natural history of the disease in fetal life remains poorly defined. The primary aim of this study was to describe the natural history of fetal aortic stenosis, and a secondary aim was to test previously published criteria designed to identify cases of emerging HLHS with the potential for a biventricular (BV) outcome after FV.

Fetal pericardial teratoma causing cardiac insufficiency: prenatal diagnosis and therapy

A 35-year-old Caucasian primigravida was referred at 25 + 0 weeks’ gestation with the diagnosis of a fetal heart tumor. B-mode sonography demonstrated a large, partly solid and partly cystic tumor arising from the surface of the right atrium next to the heart base and a massive pericardial effusion (distance from the heart to the pericardium, 10 mm; Figure 1). The tumor itself measured 28 × 21 × 29 mm. Based on the typical appearance and location a tentative diagnosis of pericardial teratoma was made. The cardiothoracic circumference ratio was 0.56 (heart biometry included neither the teratoma nor the effusion) and sequential analysis of the cardiac anatomy revealed no further anomalies. There were no signs of congestive heart failure at the time of the first presentation. Thus there was no atrioventricular (AV) valve insufficiency and ascites; the flow profiles in the ductus venosus were normal (pulsatility index for veins (PVIV) – defined as (systole – a-wave)/diastole – was 0.596); and there was a normal amount of amniotic fluid (amniotic fluid index (AFI) was 20.6 cm). Follow-up sonograms at weekly intervals showed an increase in the pulsatility indices of the ductus venosus (PVIV, 0.721) as well as an increase in the amount of amniotic fluid (AFI, 24.2 cm) at 26 + 2 weeks’ gestation. At 28 + 2 weeks’ gestation growth of the tumor (now measuring 24 × 38 × 33 mm) was noticed as well as the presence of ascites and an increase of pulsatility in the ductus venosus blood flow pattern (PVIV, 1.00). A pericardiocentesis was performed under sonographic

Intertwin cardiac status at 10-year follow-up after intrauterine laser coagulation therapy of severe twin–twin transfusion syndrome: comparison of donor, recipient and normal values

Background In twin-to-twin transfusion syndrome (TTTS), genetically identical twins are exposed to different haemodynamic conditions during fetal life, which are considered to be the cause of prenatal and postnatal cardiovascular differences between the donor and the recipient. Objective To assess intertwin differences on childhood cardiac outcome after intrauterine laser coagulation therapy (LC) of severe TTTS. Design and patients Prospective, detailed, echocardiographic follow-up of 31 twin pairs aged 9.95±0.8 years (mean±SD) with severe TTTS treated by LC, and the comparison with reference values. Results Cardiac function was normal and did not show intertwin differences in twins without structural heart disease. Discordant birth weight or birth weight <3rd centile for gestational age had no influence on blood pressure and cardiac indices. Pulmonary stenosis was more common (5/62; 8.1%) than in the general population (prevalence 0.066%, relative risk 134.4, 95% CI 42.1 to 428.8, p<0.0001) and affected both donor and recipient. Intertwin differences in late diastolic right ventricular filling (peak velocities: recipient 0.51±0.11 m/s vs donor 0.45±0.10 m/s, mean difference 0.74 m/s, 95% CI 0.23 to 1.24, p=0.009) and early septal relaxation (mean myocardial velocities: recipient −8.2±1.5 cm/s vs donor −8.9±1.2 cm/s, mean difference 0.7 cm/s, 95% CI 0.02 to 1.38, p=0.044) were found only when twins with right heart disease were included. Conclusions Despite severe prenatal cardiac involvement, childhood cardiac function is normal in the majority of surviving donors and recipients after successful LC of severe TTTS. This underlines the favourable impact of intrauterine LC on postnatal cardiovascular performance.

Prenatal diagnosis of tricuspid atresia: intrauterine course and outcome

To evaluate the intrauterine course and outcome of tricuspid atresia detected in the fetus.