Case of Complex Cardiac Anomalies in Bardet-Biedl Syndrome

Background: Bardet-Biedl syndrome (BBS) is a rare autosomal recessive ciliopathy in which cardiac involvement is infrequent and, when present, is only occasionally accompanied by disorders of thoraco-abdominal laterality. The co-occurrence of BBS with heterotaxy syndrome and complex congenital heart disease is exceptionally rare, and the surgical literature guiding management of such combined anomalies is limited. Case Presentation: We present a unique case of an 11-month-old male diagnosed with BBS exhibiting a constellation of rare cardiac anomalies, including heterotaxy syndrome with left atrial isomerism, common atrium, anterior mitral leaflet (AML) cleft, severe mitral regurgitation (MR), interrupted inferior vena cava (IVC) with azygos continuation, and a left superior vena cava (LSVC) draining into the left atrium (LA). Diagnosis was established with two-dimensional echocardiography and confirmed with cardiac computed tomography, which additionally demonstrated bilobed bilateral lungs and a left-sided liver consistent with left isomerism. Genetic testing by next-generation sequencing identified a mutation in exon 9 of the BBS2 gene. Management: The patient underwent successful surgical correction involving intra-atrial pericardial patch baffling of the common atrium, AML cleft repair, LSVC rerouting to the right superior vena cava (RSVC), and patent ductus arteriosus (PDA) ligation, with an uneventful postoperative course and stable outcome at follow-up. Conclusion: This case emphasises the importance of comprehensive multimodality evaluation and individualized surgical planning in managing complex congenital heart defects associated with BBS, and adds to the small body of literature supporting routine cardiac screening in this population.