Malformations of the first branchial cleft: duplication of the external auditory canal

Jakubı́ková, Janka; Staník, R.; Staníková, Alena

doi:10.1016/j.ijporl.2004.08.011

Cited by 16 publications

(7 citation statements)

References 7 publications

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“…We further show that the mouse EAC is entirely lined by Hoxa2-negative first arch mesenchyme, and does not develop, as previously proposed, at the first pharyngeal cleft (Jakubíková et al, 2005;Schoenwolf and Larsen, 2009). By a conditional gain-of-function approach, we show that ectopic Hoxa2 expression in first arch NCCs is alone sufficient to induce the transformation of the neural crest-derived first arch mesenchyme lining the EAC into a mirrorimage duplication of the pinna.…”

Section: Introductionsupporting

confidence: 81%

“…Therefore, the mouse EAC appears to be a first arch-derived structure that does not originate at the border between first arch Hoxa2-negative and second arch Hoxa2-positive mesenchyme, i.e. at the first pharyngeal cleft, as previously assumed (Jakubíková et al, 2005;Schoenwolf and Larsen, 2009). Auricle morphology is complex in humans, suggesting that additional components might have been recruited from the developing first arch mesenchyme, as compared with mouse.…”

Section: Research Articlesupporting

confidence: 56%

“…at the interface between the first and second arches, and to be surrounded by NCCs contributed by both arches (Jakubíková et al, 2005;Schoenwolf and Larsen, 2009 (Fig. 1J).…”

Section: The Eac Develops From First Arch Hoxa2mentioning

confidence: 99%

“…On the other hand, the ectodermal EAC has been proposed to originate at the first pharyngeal cleft and to be lined by NCCs contributed by both first and second arches (Jakubíková et al, 2005;Schoenwolf and Larsen, 2009). The hillocks eventually fuse to form the different parts of the human external ear.…”

Section: Revisiting the Embryological Origin Of The External Earmentioning

confidence: 99%

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Mouse Hoxa2 mutations provide a model for microtia and auricle duplication

et al. 2013

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SUMMARYExternal ear abnormalities are frequent in newborns ranging from microtia to partial auricle duplication. Little is known about the molecular mechanisms orchestrating external ear morphogenesis. In humans, HOXA2 partial loss of function induces a bilateral microtia associated with an abnormal shape of the auricle. In mice, Hoxa2 inactivation at early gestational stages results in external auditory canal (EAC) duplication and absence of the auricle, whereas its late inactivation results in a hypomorphic auricle, mimicking the human HOXA2 mutant condition. By genetic fate mapping we found that the mouse auricle (or pinna) derives from the Hoxa2-expressing neural crest-derived mesenchyme of the second pharyngeal arch, and not from a composite of first and second arch mesenchyme as previously proposed based on morphological observation of human embryos. Moreover, the mouse EAC is entirely lined by Hoxa2-negative first arch mesenchyme and does not develop at the first pharyngeal cleft, as previously assumed. Conditional ectopic Hoxa2 expression in first arch neural crest is sufficient to induce a complete duplication of the pinna and a loss of the EAC, suggesting transformation of the first arch neural crest-derived mesenchyme lining the EAC into an ectopic pinna. Hoxa2 partly controls the morphogenesis of the pinna through the BMP signalling pathway and expression of Eya1, which in humans is involved in branchio-oto-renal syndrome. Thus, Hoxa2 loss-and gain-of-function approaches in mice provide a suitable model to investigate the molecular aetiology of microtia and auricle duplication.

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Section: Introductionsupporting

confidence: 81%

Section: Research Articlesupporting

confidence: 56%

“…at the interface between the first and second arches, and to be surrounded by NCCs contributed by both arches (Jakubíková et al, 2005;Schoenwolf and Larsen, 2009 (Fig. 1J).…”

Section: The Eac Develops From First Arch Hoxa2mentioning

confidence: 99%

Section: Revisiting the Embryological Origin Of The External Earmentioning

confidence: 99%

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Mouse Hoxa2 mutations provide a model for microtia and auricle duplication

et al. 2013

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“…The recommended surgical technique for first branchial cleft anomalies begins with the incision used for parotid tumor excisions and proceeds with careful exposure of the facial nerve and subsequent mass resection, taking care to protect the nerve [12,13]. Although some authors recommend injecting methylene blue to display the fistula tract, we do not use such an approach because the dye may leak into neighboring tissues and obscure the surgical area.…”

Section: Discussionmentioning

confidence: 99%