Pharyngeal epithelial deletion of Tbx1 causes caudal pharyngeal arch defect but not cardiac conotruncal anomaly

Fetal Characteristics and Perinatal Outcomes in Tetralogy of Fallot Without a Ductus Arteriosus

Absence of the ductus arteriosus (DA) is common in tetralogy of Fallot (TOF), occurring in up to 30% of cases. Yet, the clinical course and fetal echocardiographic features are not well described, limiting prenatal counseling. This study examines the fetal echocardiographic characteristics and perinatal outcomes in children with TOF absent DA (TOF/ADA), comparing them to those with a DA (TOF/DA). Fetal echocardiograms were retrospectively reviewed in children with TOF evaluated at our center between 12/1/2014 and 11/1/2022. Those with complete atrioventricular septal defect, pulmonary atresia or absent pulmonary valve were excluded. Diagnosis of TOF and absence of the DA were postnatally confirmed. Fetal echocardiographic indices, clinical characteristics, and perinatal course were compared between groups. The primary outcome was intervention (surgical or catheter-based) in the first 30 days of life. Among 58 fetuses with TOF, 23 (40%) had ADA, and 35 (60%) had a DA. The groups were similar in gestational age, with similar Apgar scores. Four neonates required interventions for cyanosis: 2 with TOF/ADA and 2 with TOF/DA. One TOF/ADA patient died within the first year of life, from non-cardiac causes. Those with TOF/ADA had smaller third trimester main pulmonary artery (MPA) z-scores (- 2.75 vs. - 2.18, p = 0.02) and smaller neonatal pulmonary valve, MPA, and branch pulmonary artery z-scores. A genetic diagnosis was more common with ADA, specifically 22q11.2 deletion (22%, p = 0.03). While there were differences observed across groups, including smaller fetal and neonatal right ventricular outflow tract size and more diagnoses of 22q11.2 in ADA, absence of the DA was not linked to poorer clinical outcomes. This study expands our understanding of fetal echocardiographic findings and clinical trajectory in TOF/ADA, offering crucial insights for consultation and postnatal planning.

Multiplex droplet digital PCR for 22q11.2 microdeletions screening and DiGeorge syndrome diagnostics

BACKGROUND AND AIMS

DiGeorge syndrome (DGS) is a genetic disorder manifesting in polymorphic symptoms related to developmental abnormalities of various organs including thymus. DGS is caused by microdeletions in the 22q11.2 region between several low copy repeats (LCR) occurring in approximately 1 in 4000 live births. Diagnosis of DGS relies on phenotypic examination, qPCR, ultrasound, FISH, MLPA and NGS which can be relatively inaccurate, time-consuming, and costly.

MATERIALS AND METHODS

A novel multiplex droplet digital PCR (ddPCR) assay was designed, optimized and validated for detection and mapping 22q11.2 microdeletions by simultaneous amplification of three targets - TUPLE1, ZNF74, D22S936 - within the deletion areas and one reference target - RPP30 - as an internal control.

RESULTS

The assay reliable identified microdeletions when the template concentration was >32 copies per reaction and successfully detected LCR22A-B, LCR22A-C, LCR22A-D, and LCR22B-C deletions in clinical samples from 153 patients with signs of immunodeficiency. In patients with the microdeletions, flow cytometry detected a significant increase in B-cell and natural killer cell counts and percentages, while T-cell percentages and T-cell receptor excision circle (TREC) numbers decreased.

CONCLUSION

The designed ddPCR assay is suitable for diagnosing DGS using whole blood and blood spots.

Molecular Pathways and Animal Models of Semilunar Valve and Aortic Arch Anomalies

The great arteries of the vertebrate carry blood from the heart to the systemic circulation and are derived from the pharyngeal arch arteries. In higher vertebrates, the pharyngeal arch arteries are a symmetrical series of blood vessels that rapidly remodel during development to become the asymmetric aortic arch arteries carrying oxygenated blood from the left ventricle via the outflow tract. At the base of the aorta, as well as the pulmonary trunk, are the semilunar valves. These valves each have three leaflets and prevent the backflow of blood into the heart. During development, the process of aortic arch and valve formation may go wrong, resulting in cardiovascular defects, and these may, at least in part, be caused by genetic mutations. In this chapter, we will review models harboring genetic mutations that result in cardiovascular defects affecting the great arteries and the semilunar valves.

Pseudodiverticulum of the Cervical Esophagus With Remnant of Branchial Tissues in a Newborn: A Case Report

Congenital pseudodiverticula of the esophagus are very rare. This case report describes the presentation, management and histopathology of a peudodiverticulum of the cervical esophagus in a neonate. The infant presented with respiratory distress and a right neck mass that required surgical excision. Pathology revealed a pseudodiverticulum that contained ectopic thymic, thyroid, and parathyroid tissue within the wall of the lesion. The presence of ectopic tissues of branchial origin and an aberrant right subclavian artery suggest an error in branchial development and neural crest cell migration.