Origin of congenital coronary arterio-ventricular fistulae from anomalous epicardial and myocardial development

Coronary Artery Fistulae (CAFs) are cardiac congenital anomalies consisting of an abnormal communication of a coronary artery with either a cardiac chamber or another cardiac vessel. In humans, these congenital anomalies can lead to complications such as myocardial hypertrophy, endocarditis, heart dilatation and failure. Unfortunately, despite their clinical relevance, the aetiology of CAFs remains unknown. In this work, we have used two different species (mouse and avian embryos) to experimentally model CAFs morphogenesis. Both conditional Itga4 (alpha 4 integrin) epicardial deletion in mice and cryocauterisation of chick embryonic hearts disrupted epicardial development and ventricular wall growth, two essential events in coronary embryogenesis. Additional transcriptomics and in vitro analyses were performed to better understand how arterio-ventricular connections are originated in the embryonic heart. Our results suggest myocardial discontinuities in the developing heart promote the formation of endocardial pouch-like structures resembling human CAF. The structure of these CAF-like anomalies was compared with histopathological data from a paediatric heart CAF, showing histomorphological and immunochemical similarities, including an accumulation of smooth muscle positive cells in the pouch-like structure wall. In vitro experiments showed the abnormal contact between the epicardium and the endocardium may promote the precocious differentiation of epicardial cells to smooth muscle. Our results suggest that myocardial discontinuities in the embryonic ventricular wall promote the early contact of the endocardium with epicardial-derived coronary progenitors at the cardiac surface, leading to ventricular endocardial extrusion, precocious differentiation of coronary smooth muscle cells, and the formation of pouch-like aberrant coronary-like structures in direct connection with the ventricular lumen. Our results may provide relevant information for the early diagnosis of these congenital anomalies and the molecular mechanisms that regulate their embryogenesis.

Maternal cigarette smoking before or during pregnancy increases the risk of birth congenital anomalies: a population-based retrospective cohort study of 12 million mother-infant pairs

Background The associations of maternal cigarette smoking with congenital anomalies in offspring have been inconsistent. This study aimed to clarify the associations of the timing and intensity of maternal cigarette smoking with 12 subtypes of birth congenital anomalies based on a nationwide large birth cohort in the USA. Methods We used nationwide birth certificate data from the US National Vital Statistics System during 2016–2019. Women reported the average daily number of cigarettes they consumed 3 months before pregnancy and in each subsequent trimester during pregnancy. Twelve subtypes of congenital anomalies were identified in medical records. Poisson regression analysis was used to estimate the risk ratios (RRs) with 95% confidence intervals (CIs) for 12 subtypes of congenital anomalies associated with the timing (i.e., before pregnancy, and during three different trimesters of pregnancy) and intensity (i.e., number of cigarettes consumed per day) of maternal cigarette smoking. Results Among the 12,144,972 women included, 9.3% smoked before pregnancy and 7.0%, 6.0%, and 5.7% in the first, second, and third trimester, respectively. Maternal smoking before or during pregnancy significantly increased the risk of six subtypes of birth congenital anomalies (i.e., congenital diaphragmatic hernia, gastroschisis, limb reduction defect, cleft lip with or without cleft palate, cleft palate alone, and hypospadias), even as low as 1–5 cigarettes per day. The adjusted RRs (95% CIs) for overall birth congenital anomalies (defined as having any one of the congenital malformations above significantly associated with maternal cigarette smoking) among women who smoked 1–5, 6–10, and ≥ 11 cigarettes per day before pregnancy were 1.31 (1.22–1.41), 1.25 (1.17–1.33), and 1.35 (1.28–1.43), respectively. Corresponding values were 1.23 (1.14–1.33), 1.33 (1.24–1.42), 1.33 (1.23–1.43), respectively, for women who smoked cigarettes in the first trimester; 1.32 (1.21–1.44), 1.36 (1.26–1.47), and 1.38 (1.23–1.54), respectively, for women who smoked cigarettes in the second trimester; and 1.33 (1.22–1.44), 1.35 (1.24–1.47), and 1.35 (1.19–1.52), respectively, for women who smoked cigarettes in the third trimester. Compared with women who kept smoking before and throughout pregnancy, women who never smoked had significantly lower risk of congenital anomalies (RR 0.77, 95% CI 0.73–0.81), but women who smoked before pregnancy and quitted during each trimester of pregnancy had no reduced risk (all P > 0.05). Conclusions Maternal smoking before or during pregnancy increased the risk of several birth congenital anomalies, even as low as 1–5 cigarettes per day. Maternal smokers who stopped smoking in the subsequent trimesters of pregnancy were still at an increased risk of birth congenital anomalies. Our findings highlighted that smoking cessation interventions should be implemented before pregnancy.

Breaking constraint of mammalian axial formulae

The vertebral column of individual mammalian species often exhibits remarkable robustness in the number and identity of vertebral elements that form (known as axial formulae). The genetic mechanism(s) underlying this constraint however remain ill-defined. Here, we reveal the interplay of three regulatory pathways (Gdf11, miR-196 and Retinoic acid) is essential in constraining total vertebral number and regional axial identity in the mouse, from cervical through to tail vertebrae. All three pathways have differing control over Hox cluster expression, with heterochronic and quantitative changes found to parallel changes in axial identity. However, our work reveals an additional role for Hox genes in supporting axial elongation within the tail region, providing important support for an emerging view that mammalian Hox function is not limited to imparting positional identity as the mammalian body plan is laid down. More broadly, this work provides a molecular framework to interrogate mechanisms of evolutionary change and congenital anomalies of the vertebral column.

Deciphering the mutation spectrum in south Indian children with congenital anomalies of the kidney and urinary tract

Background Congenital anomalies of the kidney and urinary tract (CAKUT) cover a spectrum of structural malformations that result from aberrant morphogenesis of kidney and urinary tract. It is the most prevalent cause of kidney failure in children. Hence, it is important from a clinical perspective to unravel the molecular etiology of kidney and urinary tract malformations. Causal variants in genes that direct various stages of development of kidney and urinary tract in fetal life have been identified in 5–20% of CAKUT patients from Western countries. Recent advances in next generation sequencing technology and decreasing cost offer the opportunity to characterize the genetic profile of CAKUT in Indian population and facilitate integration of genetic diagnostics in care of children with CAKUT. Methods Customized targeted panel sequencing was performed to identify pathogenic variants in 31 genes known to cause human CAKUT in 69 south Indian children with CAKUT. The NGS data was filtered using standardized pipeline and the variants were classified using ACMG criteria. Genotype and phenotype correlations were performed. Results The cohort consisted of children mostly with posterior urethral valve (PUV) (39.1%), vesico-ureteric reflux (VUR) (33.3%) and multi-cystic dysplastic kidney (MCDK) (7.2%). No pathogenic or likely pathogenic variants were identified in the study. Most of our variants (n = 39, 60%) were variants of unknown significance with 25.6% (10/39) of them were identified as potentially damaging but were novel variants. Conclusions The present study did not identify any disease-causing monogenic variants in the cohort. The absence of genetic cause may be due to limitations of panel-based testing and also due to higher proportion of children with abnormalities in lower urinary tract than hypodysplasia of kidneys. Clinical, larger targeted panel or whole exome sequencing may be a better method to characterize the genetic profile of Indians patients with CAKUT.

Complete diphallia associated with unusual multiple congenital anomalies: case report and review of literatures

Background Diphallus (duplication of phallus) is rarely encountered in surgical practice with only 100 cases reported in literature. Some cases may be isolated but mostly associated with other anomalies, without clear data about its etiology. Case presentation We reported a 1-day-old newborn baby who was presented with complete duplication of the phallus, one of them being hypospadic associated with a high type imperforate anus, omphalocele, congenital pouch colon, sacral meningocele, and other congenital anomalies not reported before in such combinations. Multiple stages surgical corrective procedures were performed over a period of 4 years with 4–6 months interval between each stage, starting with the management of omphalocele and colostomy, ended by excision of the abnormal phallus with abdominoplasty and closure of colostomy. The outcome was evaluated, and literatures were reviewed in relation to types, presentations, and options for surgical correction with optimal outcomes. Conclusion A combination of diphallia and other abnormalities in our patient are not reported previously in such manner and were very difficult to be corrected. Only expert pediatric surgeons should treat such conditions as every case is unique in nature. In all conditions, the abnormal phallus should be excised, and the final aim is to achieve a continent child with cosmetically acceptable genitalia.

Congenital anomalies in Santa Catarina: case distribution and trends in 2010–2018

Objective: To evaluate the distribution of cases of congenital anomalies in the state of Santa Catarina by health macro-region, to determine the frequency according to maternal and neonatal variables, to estimate the related mortality, and the trends in the period 2010–2018. Methods: An ecological time-series study with secondary data on congenital anomalies and the sociodemographic and health variables of mothers and newborns living in Santa Catarina, from 2010 to 2018. For temporal trend analysis, generalized linear regression was performed using the Prais-Winsten method with robust variance. Results: The average prevalence of congenital anomalies in the period was 8.9 cases per 1,000 live births, being 9.4 cases by 1,000 live births in 2010 and, in 2018, 8.2/1,000. The trend remained stable in the analyzed period. The major malformations were musculoskeletal, hip, and foot malformations, with a proportion ≥30%. There was a higher prevalence of congenital anomalies in low birthweight, preterm, male livebirths with Apgar≤7, born by cesarean section, mothers of older age (≥40 years), and less educated (less than eight years of study). Infant mortality due to congenital malformations was 2.6 deaths/1,000 live births, representing about 25.8% of the total infant deaths in the period. Conclusions: The frequency of congenital anomalies and the mortality with anomalies was stable in the studied period in Santa Catarina. The presence of anomalies was associated with low birth weight, prematurity, and low Apgar score. The highest proportion of congenital anomalies was in the musculoskeletal system.