Background: The aim of the study was to document cardiovascular clinical findings, cardiac imaging and laboratory markers in children presenting with the novel multisystem inflammatory syndrome (MIS-C) associated with COVID-19 infection. Methods: A real-time internet-based survey endorsed by the Association for European Paediatric and Congenital Cardiologists (AEPC) Working Groups for Cardiac Imaging and Cardiovascular Intensive Care. Inclusion criteria was children 0-18 years admitted to hospital between February 1 and June 6, 2020 with diagnosis of an inflammatory syndrome and acute cardiovascular complications. Results: A total of 286 children from 55 centers in 17 European countries were included. The median age was 8.4 years (IQR 3.8-12.4 years) and 67% were males. The most common cardiovascular complications were shock, cardiac arrhythmias, pericardial effusion and coronary artery dilatation. Reduced left ventricular ejection fraction was present in over half of the patients and a vast majority of children had raised cardiac troponin (cTnT) when checked. The biochemical markers of inflammation were raised in majority of patients on admission: elevated CRP, serum ferritin, procalcitonin, NT-proBNP, IL-6 level and D-dimers. There was a statistically significant correlation between degree of elevation in cardiac and biochemical parameters and need for intensive care support (p <0.05). Polymerase chain reaction (PCR) for SARS-CoV-2 was positive in 33.6% while IgM and IgG antibodies were positive in 15.7% and IgG 43.6 % cases, respectively when checked. One child died in the study cohort. Conclusions: Cardiac involvement is common in children with multisystem inflammatory syndrome associated with Covid-19 pandemic. A majority of children have significantly raised levels of NT pro-BNP, ferritin, D-dimers and cardiac troponin in addition to high CRP and procalcitonin levels. Compared to adults with Covid-19, mortality in children with MIS-C is uncommon despite multi-system involvement, very elevated inflammatory markers and need for intensive care support.

The risk of intervention was higher in individuals with Noonan syndrome and pulmonary stenosis carrying PTPN11 mutations. Overall, mortality was relatively low, even though the specific association between HCM, biventricular outflow tract obstructions and PTPN11 mutations appeared to be associated with early mortality, including immediate post-operative events and sudden death.

Congenital heart diseases (CHDs) and cardiovascular abnormalities are one of the pillars of clinical diagnosis of 22q11.2 deletion syndrome (22q11.2DS) and still represent the main cause of mortality in the affected children. In the past 30 years, much progress has been made in describing the anatomical patterns of CHD, in improving their diagnosis, medical treatment, and surgical procedures for these conditions, as well as in understanding the underlying genetic and developmental mechanisms. However, further studies are still needed to better determine the true prevalence of CHDs in 22q11.2DS, including data from prenatal studies and on the adult population, to further clarify the genetic mechanisms behind the high variability of phenotypic expression of 22q11.2DS, and to fully understand the mechanism responsible for the increased postoperative morbidity and for the premature death of these patients. Moreover, the increased life expectancy of persons with 22q11.2DS allowed the expansion of the adult population that poses new challenges for clinicians such as acquired cardiovascular problems and complexity related to multisystemic comorbidity. In this review, we provide a comprehensive review of the existing literature about 22q11.2DS in order to summarize the knowledge gained in the past years of clinical experience and research, as well as to identify the remaining gaps in comprehension of this syndrome and the possible future research directions.

Familial recurrence is one of the classic patterns for the clinical presentation of congenital heart disease (CHD). In recent years, many groups studied empiric recurrence risk in these heart defects, and the aim of this review was to analyse the patterns of inheritance detected in different types of CHD, including atrioventricular canal defect, tetralogy of Fallot, transposition of the great arteries, left-sided obstructions and atrial septal defect. These studies may influence clinical practise guidelines through accurate genetic counselling, but also, they may have important implications in the knowledge of genetic and pathogenetic mechanisms of CHD.

Advances in genetics allowed a better definition of the role of specific genetic background in the etiology of syndromic congenital heart defects (CHDs). The identification of a number of disease genes responsible for different syndromes have led to the identification of several transcriptional regulators and signaling transducers and modulators that are critical for heart morphogenesis. Understanding the genetic background of syndromic CHDs allowed a better characterization of the genetic basis of non-syndromic CHDs. In this sense, the well-known association of typical CHDs in Down syndrome, 22q11.2 microdeletion and Noonan syndrome represent paradigms as chromosomal aneuploidy, chromosomal microdeletion and intragenic mutation, respectively. Area covered: For each syndrome the anatomical features, distinctive cardiac phenotype and molecular mechanisms are discussed. Moreover, the authors include recent genetic findings that may shed light on some aspects of still unclear molecular mechanisms of these syndromes. Expert commentary: Further investigations are needed to enhance the translational approach in the field of genetics of CHDs. When there is a well-established definition of genotype-phenotype (reverse medicine) and genotype-prognosis (predictive and personalized medicine) correlations, hopefully preventive medicine will make its way in this field. Subsequently a reduction will be achieved in the morbidity and mortality of children with CHDs.