Abstract 14317: The Prevalence of Motile Ciliary Gene Variants in Children With Transposition of the Great Arteries and Tetralogy of Fallot

Abstract

Introduction: Motile ciliary dysfunction plays a central role in the pathogenesis of respiratory abnormalities and congenital heart disease (CHD). The role of ciliary gene variants in the non-heterotaxic CHD population is not well characterised. Methods: This single-centre retrospective cohort study aimed to determine the prevalence of Primary Ciliary Dyskinesia (PCD) gene variants in children with isolated Transposition of the Great Arteries (TGA) and Tetralogy of Fallot (TOF). Patients with whole genome sequencing between 2008-2018 were included. We identified pathogenic (P) or likely pathogenic (LP) single-nucleotide variants (SNVs) and short insertion/deletions (indels) in coding regions of 45 genes known to cause PCD. Patient characteristics and associated respiratory outcomes were evaluated from chart reviews. Results: PCD gene variants were found in 2.9% (5/172) TGA and 3.8% (10/264) TOF patients. Thirteen probands were heterozygous for P/LP SNVs/ indels; CCDC40 N=6, DNAH11 N=2, SPAG1 N=2 and one each of DNAH8/DNAAF1/ARMC4. Two were compound heterozygotes for variants in DNAH11 and DNAH8. At last follow-up, mean age was 14.5 years (SD 6.8, 57.9% male) and 7 deaths had occurred. Asthma was diagnosed in 10.5% TGAs and 8.1% TOFs with 3.9% and 7.3% respectively requiring hospitalisation for primary respiratory illness. In the variant positive subgroup, 5/15 had respiratory abnormalities - bronchiectasis (N = 1), asthma (N = 2), neonatal cough (N = 1), ventilator-associated pneumonia (N = 2). Additional cardiac anomalies occurred in 53% (8/15) - abnormal systemic veins (N = 3), situs inversus, dextrocardia (N = 1), right arch (N = 5), hypoplastic right ventricle (N = 1). An abnormal coronary pattern was seen in 4/5 TGAs. Vaginal and renal agenesis each occurred in 1 patient. Conclusions: Our findings suggest a high prevalence and potential association of ciliary gene variants with respiratory outcomes and situs anomalies in non-heterotaxy CHD.