The pulmonary arterial sling originates from a failure of development of the proximal portion of the left sixth aortic arch, resulting in an anomalous left pulmonary artery
[ncbi.nlm.nih.gov]
[…] particularly pulmonary artery sling) or pulmonary valves.
[ncbi.nlm.nih.gov]
see these terms), pulmonary (artery sling, with or without tracheal stenosis), genitourinary (hypospadias, cryptorchidism, vesicoureteric reflux and hydronephrosis), ocular
[orpha.net]