Fahad Alhabshan

FBXO22 encodes an F-box protein which acts as a substrate-recognition component of the SKP1-CUL1-F-box (SCF) E3 ubiquitin ligase complex. Despite its known roles in the post-translational ubiquitination and degradation of specific substrates, including histone demethylases, the impact of FBXO22 on human development remains unknown. Here, we characterize a pleiotropic syndrome with prominent prenatal onset growth restriction and notable neurodevelopmental delay across 14 cases from 12 families. Through exome and genome sequencing, we identify three distinct homozygous loss-of-function FBXO22 variants segregating with the disease: p.(Arg53Serfs*13), p.(Pro3Leufs*3) and p.(Val240Alafs*6), all predicted to lead to premature translation termination due to frameshift effects. We confirm that patient-derived primary fibroblasts are bereft of FBXO22 and show increased levels of the known substrate histone H3K9 demethylase KDM4B. Accordingly, we delineate a unique epigenetic signature for this disease in peripheral blood. Altogether, we identify and demonstrate that FBXO22 deficiency leads to a pleiotropic syndrome in humans encompassing growth restriction and neurodevelopmental delay, the pathogenesis of which may be explained by broad chromatin alterations.

Frank–Ter Haar syndrome (FTHS), sometimes referred to as Ter Haar syndrome, is a rare hereditary disorder that manifests in skeletal, cardiac, and ocular anomalies, including hypertelorism, glaucoma, prominent eyes, and facial abnormalities. In this study, we performed whole-exome sequencing (WES) to identify the genetic component responsible for the phenotype of the index patient, a male infant born to a consanguineous family from Saudi Arabia. The analysis revealed a homozygous missense variant, c.280C>G, in the SH3PXD2B gene, which cosegregates with the familial phenotype with a plausible autosomal-recessive mode of inheritance, indicating a potential disease-causing association. The SH3PXD2B gene encodes a TKS4 podosome adaptor protein that regulates the epidermal growth factor signaling pathway. This study validates the critical function of the TKS4 podosome protein by suggesting a common mechanism underlying the pathogenesis of FTHS.

Background: Yasui procedure is surgical repair intended to preserve biventricular function for patients with left ventricle outflow tract obstruction associated with aortic arch lesions and ventricular septal defect.Methods: Retrospective chart review analysis of all patients who had Yasui procedure (2008–2020) comparing midterm outcome of one versus two stage repair.Results: Twenty patients (70% female) underwent Yasui procedure in our center. Eight patients (40%) had left ventricle outflow tract obstruction /interrupted aortic arch, 7 patients (35%) had left ventricle outflow tract obstruction /coarctation of aorta, 3 patients (15%) had double outlet ventricle and ventricular septal defect that were unattainable for tunneling to one of the semilunar valves without creating obstruction, and 2 patients (10%) had aortic atresia with hypoplastic aortic arch. All patients had associated ventricular septal defect. Fifteen patients (75%) had one-stage repair and 5 patients (25%) had two-stage repair. Means age and weight for one and two-stage repair were 1.3 ± 2 months, 13.4 ± 11.5 months and 3.3 ± 0.6 kg, 7.8 ± 3.4 kg, respectively. During follow up, 8 patients (40%) required re- intervention, mainly for right ventricle–pulmonary artery conduit either dilation or replacement. The average duration of follow up was 5 years with nil mortality.Conclusion: Yasui procedure is effective approach for children who have left ventricle outflow tract obstruction associated with aortic arch anomalies and ventricular septal defect. Survival rate with single or staged repair is comparably good. During the first 5 year of follow up, nearly 40% of operated patients required re-intervention.