Persistent Fifth Aortic Arch Associated with 22q11.2 Deletion Syndrome

Persistent fifth aortic arch: a comprehensive literature review

Persistent fifth aortic arch (PFAA) is an extremely rare congenital cardiovascular anomaly resulting from the failure of the fifth aortic arch to degenerate during embryonic development; it is often associated with various other cardiovascular anomalies. Despite being first reported by Van Praagh in 1969, there have been only a few individual case reports. Owing to its rarity and lack of comprehensive understanding, PFAA is often misdiagnosed or missed diagnosed during clinical. Thus, this review aimed to summarise the embryonic development, pathological classification, imaging diagnosis, and clinical treatment of PFAA to improve its overall understanding, ultimately helping in accurate diagnosis and treatment.

A new association of Oculoauriculovertebral spectrum and persistent fifth aortic arch -double lumen aorta: a case report

Background

Oculo-auriculo-vertebral spectrum is a heterogeneous group of genetic disorder, also known as Goldenhar Syndrome, which has several phenotypic features including craniofacial anomalies, cardiac, vertebral and central nervous system defects. Cardiovascular anomalies include ventricular septal defects, atrial septal defects, patent ductus arteriosus, Tetralogy of Fallot, double outlet right ventricle, aberrant right subclavian artery, coarctation of aorta, transposition of the great arteries, double inlet left ventricle, cor triatriatum, pulmonary artery stenosis, aortic stenosis, persistent left superior vena cava, partially or totally abnormal pulmonary venous return and bicuspid aortic valve. Persistent fifth aortic arch, also named as double lumen aortic arch, is a very rare cardivascular anomaly and usually associate other cardiac defects.

Case presentation

We present a 7 month old patient with oculo-auriculo-vertebral spectrum signs as facial asymmetry, short neck, choanal atresia, cleft palate, bilateral preauricular skin tags, bilateral hypoplastic ear lobes, epibulbar dermoid cyst, rib, vertebrae and cardiovascular anomalies. Cardiovascular anomalies detected with echocardiography and computed tomography were malalignment ventricular septal defect and double lumen aorta, known as persistent fifth aortic arch.

Conclusion

Various cardiovascular anomalies may accompany Goldenhar Syndrome. We present a case with persistent fifth aortic arch and Oculo-auriculo-vertebral spectrum and this is a new association that was not reported before in the literature.

DiGeorge syndrome and anomalous right aortic arch with arch-on-arch and figure-of-eight configurations: Aortic sac maldevelopment and left brachiocephalic artery abnormal remodeling

We report a 6-month-old female infant with deletion of chromosome 22q11.2 (DiGeorge/VFS TUPLE 1), normal atrial arrangement with concordant atrioventricular connection, pulmonary atresia, large subaortic ventricular septal defect, diminutive native pulmonary arteries, a characteristic weird-shape right aortic arch with arch-on-arch appearance and figure of 8 configuration. We presented the cardiac computed tomographic angiographic and cardiac angiographic features. Using Autodesk 3ds Max 2018 software, we explained and illustrated the speculative embryologic etiology of this bizarre aortic archanomaly with the extensive abnormal remodeling of the left brachiocephalic artery, based on a “five-embryonic aortic arches” concept. As to the best of the authors' knowledge, this is the first report of a genetically confirmed case of DiGeorge syndrome and an exceedingly rare type of right aortic arch anomaly with embryologic explanation according to the “five-embryonic-aortic-arches” concept. It seems that the constellation of pulmonary atresia, bizarreshaped right aortic arch due to abnormal development of the aortic sac, and abnormal remodeling of the left brachiocephalic artery may be strongly suggestive of DiGeorge syndrome.

Persistent fifth aortic arch: the "great pretender" in clinical practice

Persistence of the embryonic "fifth aortic arch" in postnatal life is a rare, enigmatic - and at times controversial - condition, with variable anatomical forms and physiological consequences. First described in humans over 40 years ago by Van Praagh, the condition was labelled the "great pretender" by Gerlis 25 years later, because of its apparent propensity to mimic anatomically similar structures. Despite many subsequent case reports citing the condition, the true developmental origin of these structures remains unresolved, and has been the subject of debate among embryologists for more than a century. A persistent fifth aortic arch has been defined as an extrapericardial structure, arising from the ascending aorta opposite or proximal to the brachiocephalic artery, and terminating in the dorsal aorta or pulmonary arteries via a persistently patent arterial duct. This description may therefore encompass various anatomical forms, such as a unilateral double-lumen aortic arch, an unrestrictive aortopulmonary shunt, or a critical vascular channel for either the systemic or pulmonary circulation. The physiological properties of these vessels, such as their response to prostaglandins, may also be unpredictable. In this article, we demonstrate a number of cases that fulfil the contemporary definition of "persistent fifth aortic arch" while acknowledging the embryological controversies associated with this term. We also outline the key diagnostic features, particularly with respect to the use of new cross-sectional imaging techniques.

How frequent is the fifth arch artery?

Although usually shown in embryology textbooks, the presence of the fifth pair of pharyngeal arch arteries has long been controversial. To the best of our knowledge, six pairs of bilaterally symmetrical arteries developing within the pharyngeal arches are yet to be found in any mammalian or avian species. Collateral channels between the distal ends of the fourth and sixth arch arteries, in contrast, have been found in up to half of all developing mouse embryos. In only one human embryo, again to the best of our knowledge, has a channel been found that extends from the aortic sac to the dorsal aorta, and hence qualifies as an arch artery. Despite these confounding factors in terms of the developmental heritage of the fifth arch arteries, the purported channels are invoked with increasing frequency to describe various lesions discovered in the setting of the congenitally malformed heart. Persistence of the artery of the fifth arch was initially proposed to explain double-barrelled aorta. It was subsequently proposed to account for various systemic-to-pulmonary channels feeding the pulmonary circulation in the setting of pulmonary atresia. It has also been claimed to persist so as to explain abnormal branching of the brachiocephalic arteries from the aortic arch. In the light of the ongoing doubts concerning the existence of the arteries of the fifth arch themselves, we have reviewed the various descriptions of purported fifth arch arteries within the world literature. We have then sought to validate the descriptions on the basis of our own understanding of development, for this purpose providing images of the remoulding arch arteries in the mouse so as to substantiate our conclusions. While accepting that our own interpretations are speculative, we suggest that more convincing alternative explanations can be advanced to account for the majority of lesions currently interpreted on the basis of persistence of the arteries of the fifth arches. Although the interpretations do not necessarily change the therapeutic approaches to the channels, appropriate description is important in terms of their classification.

The role of modern imaging techniques in the diagnosis of malposition of the branch pulmonary arteries and possible association with microdeletion 22q11.2

Malposition of the branch pulmonary arteries is a rare malformation with two forms. In the typical form, pulmonary arteries cross each other as they proceed to their respective lungs. The “lesser form” is characterised by the left pulmonary artery ostium lying directly superior to the ostium of the right pulmonary artery, without crossing of the branch pulmonary arteries. Malposition of the branch pulmonary arteries is often associated with other congenital heart defects and extracardiac anomalies, as well as with 22q11.2 microdeletion. We report three infants with crossed pulmonary arteries and one adolescent with “lesser form” of the malformation. The results suggest that diagnosis of malposition of the branch pulmonary arteries could be challenging if based solely on echocardiography, whereas modern imaging technologies such as contrast computed tomography and magnetic resonance angiography provide reliable establishment of diagnosis. In addition, we performed the first molecular characterisation of the 22q11.2 region among patients with malposition of the branch pulmonary arteries and revealed a 3-megabase deletion in two out of four patients

A rare form of persistent right aorta arch in linkage disequilibrium with the DiGeorge critical region on CFA26 in German Pinschers

Persistent right aortic arch (PRAA) is a congenital vascular ring anomaly common in several dog breeds. In German Pinscher, the disorder is characterized by a left retroesophageal subclavian artery in combination with a ligamentum arteriosum originating at the aberrant left subclavian artery (PRAA-SA-LA). In this study, we genotyped 38 microsatellite markers on canine chromosome 26 (CFA26) in German Pinschers and tested them for linkage and association. We found a chromosome-wide significantly linked genomic region on CFA26, which corresponds to the human DiGeorge syndrome critical region (DGCR). Therefore, we analyzed sequences from 13 genes of DGCR and the canine t-box gene TBX1. We identified a total of 26 polymorphisms in German Pinschers. Three of these SNPs located within TBX1 and one in the mitochondrial ribosomal protein L40 gene (MRPL40) were associated with the PRAA-SA-LA phenotype in German Pinscher. Despite linkage and association between PRAA-SA-LA and the canine DGCR, none of these mutations appeared responsible for PRAA-SA-LA. As the orthologue human region on HSA22q11.2 is known for high susceptibility to genomic rearrangements, we suspect that in German Pinschers, chromosomal aberrations might cause PRAA-SA-LA.

Mirror-image type D interrupted aortic arch: a novel cardiac phenotype providing some perspective in the del22q11.2 syndrome

A 1-day-old baby boy was referred from a local obstetric clinic due to feeble crying, tachypnea, and tachycardia. Two-dimensional echocardiography with Doppler and multidetector computer tomography showed mirror-image type D interrupted aortic arch, conotruncal ventricular septal defect, and patent ductus arteriosus. Emergency cardiac surgery by a biventricular Norwood procedure was performed to relieve his symptom and sign of congestive heart failure successfully. Thymus could not be seen by surgical exploration of the superior mediastinum. Serum C-terminal parathyroid hormone was decreased to less than the normal lower limit. Cytogenetic analysis and fluorescence in situ hybridization study of blood revealed a deletion in chromosome 22q11.2. To the best of our knowledge, mirror-image type D interrupted aortic arch has never been reported in patients with the del22q11.2 syndrome in the English literature. This unusual aortic arch anomaly may provide us a new perspective in the spectrum of cardiovascular malformations in the del22q11.2 syndrome and advocate 22q11.2 deletion as one of the genetic causes of some rare aortic arch anomalies and their correspondent mirror-images.

Congenital stridor and wheezing as harbingers of the del22q11.2 syndrome presenting cardiovascular malformations of right aortic arch, aberrant left subclavian artery, Kommerell's diverticulum, and left ligamentum arteriosum

A complete vascular ring composed of right aortic arch, aberrant left subclavian artery with Kommerell's diverticulum, and left ligamentum arteriosum was diagnosed by barium esophagography, echocardiography, angiography, and multidetector computed tomography of chest in an 18-day-old male neonate who presented with remarkable inspiratory stridor, expiratory wheezing, postprandial vomiting, and dysphagia since birth, and survived surgical division of the left ligamentum arteriosum, resection of the Kommerell's diverticulum, and reimplanation of the left subclavian artery to the left common carotid artery. Cytogenetic analysis and fluorescence in situ hybridization study of his blood revealed chromosome 22q11.2 deletion, with a karyotype of 46,XY.ish del(22)(q11.2 q11.2). A constellation of right aortic arch, aberrant left subclavian artery with Kommerell's diverticulum, and left ligamentum arteriosum in neonates may cause refractory stridor, wheezing, vomiting, and dysphagia, which can serve as harbingers of the del22q11.2 syndrome.