Altered contractility, Ca2+ transients, and cell morphology seen in a patient-specific iPSC-CM model of Ebstein's anomaly with left ventricular noncompaction.

Patients with two congenital heart diseases (CHDs), Ebstein's anomaly (EA) and left ventricular noncompaction (LVNC), suffer higher morbidity than either CHD alone. The genetic etiology and pathogenesis of combined EA/LVNC remain largely unknown. We investigated a familial EA/LVNC case associated with a variant (p.R237C) in the gene encoding Kelch-like protein 26 (KLHL26) by differentiating induced pluripotent stem cells (iPSCs) generated from affected and unaffected family members into cardiomyocytes (iPSC-CMs) and assessing iPSC-CM morphology, function, gene expression, and protein abundance. Compared with unaffected iPSC-CMs, CMs containing the KLHL26 (p.R237C) variant exhibited aberrant morphology including distended endo(sarco)plasmic reticulum (ER/SR) and dysmorphic mitochondria and aberrant function that included decreased contractions per minute, altered calcium transients, and increased proliferation. Pathway enrichment analyses based on RNASeq data indicated that the "structural constituent of muscle" pathway was suppressed, whereas the "ER lumen" pathway was activated. Taken together, these findings suggest that iPSC-CMs containing this KLHL26 (p.R237C) variant develop dysregulated ER/SR, calcium signaling, contractility, and proliferation.NEW & NOTEWORTHY We demonstrate here that iPSCs derived from patients with Ebstein's anomaly and left ventricular noncompaction, when differentiated into cardiomyocytes, display significant structural and functional changes that offer insight into disease pathogenesis, including altered ER/SR and mitochondrial morphology, contractility, and calcium signaling.

Integrated microRNA and mRNA Expression Profiling Identifies Novel Targets and Networks Associated with Ebstein's Anomaly.

Little is known about abundance level changes of circulating microRNAs (miRNAs) and messenger RNAs (mRNA) in patients with Ebstein's anomaly (EA). Here, we performed an integrated analysis to identify the differentially abundant miRNAs and mRNA targets and to identify the potential therapeutic targets that might be involved in the mechanisms underlying EA. A large panel of human miRNA and mRNA microarrays were conducted to determine the genome-wide expression profiles in the blood of 16 EA patients and 16 age and gender-matched healthy control volunteers (HVs). Differential abundance level of single miRNA and mRNA was validated by Real-Time quantitative PCR (RT-qPCR). Enrichment analyses of altered miRNA and mRNA abundance levels were identified using bioinformatics tools. Altered miRNA and mRNA abundance levels were observed between EA patients and HVs. Among the deregulated miRNAs and mRNAs, 76 miRNAs (49 lower abundance and 27 higher abundance, fold-change of ≥2) and 29 mRNAs (25 higher abundance and 4 lower abundance, fold-change of ≥1.5) were identified in EA patients compared to HVs. Bioinformatics analysis identified 37 pairs of putative miRNA-mRNA interactions. The majority of the correlations were detected between the lower abundance level of miRNA and higher abundance level of mRNA, except for let-7b-5p, which showed a higher abundance level and their target gene, SCRN3, showed a lower abundance level. Pathway enrichment analysis of the deregulated mRNAs identified 35 significant pathways that are mostly involved in signal transduction and cellular interaction pathways. Our findings provide new insights into a potential molecular biomarker(s) for the EA that may guide the development of novel targeting therapies.

Thiamine-responsive megaloblastic anemia syndrome with Ebstein anomaly: a case report.

UNLABELLED: Thiamine-responsive megaloblastic anemia (TRMA) or Roger syndrome is a rare autosomal recessive disorder characterized by the occurrence of multiple clinical manifestations including megaloblastic anemia, diabetes mellitus, and sensorineural deafness. A few patients have been also described with congenital cardiac malformations. The patients usually respond to treatment with pharmacological doses of thiamine. Mutations in the SLC19A2 gene, located at chromosome 1q24.2, are responsible for this syndrome. Here, we present two new Iranian TRMA patients who were homozygous for c.697C > T mutation in the SLC19A2 gene. On follow-up, one of the patients showed Ebstein anomaly. CONCLUSION: The present study confirms the variability of the clinical manifestations caused by the same mutation within patients with TRMA syndrome. Therefore, follow-up of the affected children should be considered.

Peak oxygen uptake correlates with disease severity and predicts outcome in adult patients with Ebstein's anomaly of the tricuspid valve.

BACKGROUND: Ebstein's anomaly of the tricuspid valve often results in biventricular dysfunction and functional deterioration. Little is known about the relation between exercise capacity, disease severity and outcome in adults with Ebstein's anomaly. METHODS: Data on all patients with Ebstein's anomaly of the tricuspid valve who underwent cardiopulmonary exercise testing in our tertiary center were collected. The relation between exercise parameters, anatomic severity (Glasgow outcome score) and the combined end-point of death, non-elective hospitalization and surgical repair was studied using Cox regression analysis. RESULTS: A total of 51 adult patients fulfilled inclusion criteria (49% male, mean age 37.8±13.6 years). Mean peak oxygen uptake (peak VO2) was 63.2±18.7% of predicted, the slope of ventilation per unit of carbon dioxide output (VE/VCO2 slope) 37.4±11.4, heart rate reserve (HRR) 23.6±22.7 bpm. A significantly lower peak VO2 was found in patients with a higher Glasgow outcome score, higher cardiothoracic ratio and documented atrial shunt. Peak VO2 (HR for value <60% of predicted 3.47, 95% CI: 1.28­9.44, p=0.015) and HRR (HR for value <25 bpm 3.07, 95% CI: 1.24­7.61, p=0.016) were significant predictors of outcome, the former being the strongest on multivariable analysis. CONCLUSIONS: Reduced exercise capacity in patients with Ebstein's anomaly relates to severity of the underlyingdisease and is a strong and independent predictor of outcome. Cardiopulmonary exercise testing should be incorporated in the follow-up and risk stratification of patients with this relatively uncommon and challenging cardiac defect.