Craniofacial malformations: intrinsic <i>vs</i> extrinsic neural crest cell defects in Treacher Collins and 22q11 deletion syndromes

Walker, M. B.; Trainor, Paul A.

doi:10.1111/j.0009-9163.2006.00615.x

Cited by 50 publications

(41 citation statements)

References 77 publications

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“…2 The manifestation and severity of the congenital abnormality depend on the alteration of gene-expression profiles. 2,3 The pluripotent nature of synchronously migrating cells is thought to, at least partially, explain the appearance and pattern of mesenchymal and epithelial abnormalities seen with syndromic defects of the BAs. Multiple craniofacial syndromes have been shown to result from an abnormality in the quantity or quality of neural crest cell migration (ie, TCS and VCFS).…”

Section: Embryology Of the First And Second Bas And Associated Structmentioning

confidence: 99%

“…[10][11][12][13] Specific neural crest cell segregation is critical to prevent fusions of the ectodermal and mesenchymal elements and also to prevent mixing of neural crest cells with different genetic constitutions. 3 This migrational isolation leads each pharyn- geal arch to consist of a core of specific mesenchymal tissue covered on the outside by surface ectoderm and on the inside by epithelium of endodermal origin. The core of each arch comprises neural crest cells that migrate along the BAs, helping to form the characteristic muscular, cranial nerve, and arterial component of each arch (Table 1).…”

Section: Embryology Of the First And Second Bas And Associated Structmentioning

confidence: 99%

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Syndromes of the First and Second Branchial Arches, Part 1: Embryology and Characteristic Defects

Johnson¹,

Moonis²,

Green³

et al. 2010

AJNR Am J Neuroradiol

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SUMMARY:A variety of congenital syndromes affecting the face occur due to defects involving the first and second BAs. Radiographic evaluation of craniofacial deformities is necessary to define aberrant anatomy, plan surgical procedures, and evaluate the effects of craniofacial growth and surgical reconstructions. High-resolution CT has proved vital in determining the nature and extent of these syndromes. The radiologic evaluation of syndromes of the first and second BAs should begin first by studying a series of isolated defects: CL with or without CP, micrognathia, and EAC atresia, which compose the major features of these syndromes and allow more specific diagnosis. After discussion of these defects and the associated embryology, we proceed to discuss the VCFS, PRS, ACS, TCS, Stickler syndrome, and HFM.ABBREVIATIONS: ACS ϭ auriculocondylar syndrome; BA ϭ branchial arch; CL ϭ cleft lip; CL/P ϭ cleft lip/palate; CP ϭ cleft palate; EAC ϭ external auditory canal; HFM ϭ hemifacial microsomia; MDCT ϭ multidetector CT; PRS ϭ Pierre Robin sequence; TCS ϭ Treacher Collins syndrome; VCFS ϭ velocardiofacial syndrome R adiographic evaluation of craniofacial deformities is necessary to define aberrant anatomy, plan surgical procedures, and evaluate the effects of craniofacial growth and surgical reconstructions.1 The recent rapid proliferation of MDCT is due, in part, to the increased utility of this technique for multiplanar bone and soft-tissue imaging. The definition of fine bony structure of the craniofacial anatomy on CT images is unmatched by other modalities. There has also been increased demand for treatment planning along with the advances in high-resolution CT evaluation and 3D reconstruction techniques.Knowledge of the genetic basis of human disease and its effect on embryologic development has expanded greatly in recent years. Disorders of the first and second BA are generally thought to result from a combination of inadequate migration and inadequate formation of facial mesenchyma. Because many structures of the head and neck migrate during fetal development, an understanding of embryologic development helps determine the origin and nature of congenital lesions. Familiarity with craniofacial embryology and its associated effects on resultant anatomy also leads to a better understanding of the pathophysiologic basis of craniofacial syndromes. Additionally, it helps to establish a search pattern for characteristic radiologic features of many of these anomalies.Part 1 of this review establishes the embryology, developmental anatomy, clinical symptoms, and characteristic imaging features of the isolated defects that compose some of the major features of the syndromes of the first and second BAs. Part 2 of this review discusses the syndromes and their radiographic features: PRS, HFM, ACS, TCS, Stickler syndrome, and VCFS. When applicable, the disorders number of the public data base of bibliographic information about human genes and genetic disorders-the Online Mendelian Inheritance in Man (http://www.ncbi.nlm.nih....

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Section: Embryology Of the First And Second Bas And Associated Structmentioning

confidence: 99%

Section: Embryology Of the First And Second Bas And Associated Structmentioning

confidence: 99%

Syndromes of the First and Second Branchial Arches, Part 1: Embryology and Characteristic Defects

Johnson¹,

Moonis²,

Green³

et al. 2010

AJNR Am J Neuroradiol

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“…Precise cranial NCC movement from the hindbrain to the pharyngeal arches is an important developmental event, with defects in emigration, migration or survival leading to craniofacial dysmorphologies and possible death Simpson, 2006, Walker andTrainor, 2006). However, our analysis of NCC development and distribution in Ednra-/-embryos suggests that most NCCs emigrate properly from the neural tube and reach the pharyngeal arches in the absence of Ednra signaling, arguing against gross defects in NCC migration as a cause of missing or malformed structures in Ednra-/-mice.…”

Section: Absence Of Ednra Signaling Does Not Disrupt Migration Of Nccmentioning

confidence: 99%

Fate of cranial neural crest cells during craniofacial development in endothelin-A receptor-deficient mice

Abe¹,

Ruest²,

Clouthier³

2007

Int. J. Dev. Biol.

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Most of the bone, cartilage and connective tissue of the lower jaw is derived from cranial neural crest cells (NCCs) arising from the posterior midbrain and hindbrain. Multiple factors direct the patterning of these NCCs, including endothelin-1-mediated endothelin A receptor (Edn1/Ednra) signaling. Loss of Ednra signaling results in multiple defects in lower jaw and neck structures, including homeotic transformation of lower jaw structures into upper jawlike structures. However, since the Ednra gene is expressed by both migrating and post-migrating NCCs, the actual function of Ednra in cranial NCC development is not clear. Ednra signaling could be required for normal migration or guidance of NCCs to the pharyngeal arches or in subsequent events in post-migratory NCCs, including proliferation and survival. To address this question, we performed a fate analysis of cranial NCCs in Ednra-/-embryos using the R26R;Wnt1-Cre reporter system, in which Cre expression within NCCs results in permanent β-galactosidase activity in NCCs and their derivatives. We find that loss of Ednra does not detectably alter either migration of most cranial NCCs into the mandibular first arch and second arch or their subsequent proliferation. However, mesenchymal cell apoptosis is increased two fold in both E9.5 and E10.5 Ednra-/-embryos, with apoptotic cells being present in and just proximal to the pharyngeal arches. Based on these studies, Ednra signaling appears to be required by most cranial NCCs after they reach the pharyngeal arches. However, a subset of NCCs appear to require Ednra signaling earlier, with loss of Ednra signaling likely leading to premature cessation of migration into or within the arches and subsequent cell death.

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“…However, the craniofacial defects seen in XLOS are suggestive of underlying problems with CNC development (Walker and Trainor, 2006), and yet no studies have examined the functions of Mid1 (and by inference PP2A activity) at developmental stages corresponding with CNC formation, delamination and migration. We therefore chose to examine the expression and functions of cMid1 during the developmental stages when CNC are migrating to their targets and subsequently contributing to cranial gangliogenesis.…”

Section: Introductionmentioning

confidence: 99%

Regulation of PP2A activity by Mid1 controls cranial neural crest speed and gangliogenesis

Latta

Golding

2012

Mechanisms of Development

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X-linked Opitz syndrome (XLOS), caused by mutation in the MID1 gene, is a midline malformation syndrome with obvious craniofacial abnormalities. Because cranial neural crest cells (CNC) play a pivotal role in cranial morphogenesis, we examined the spatio-temporal expression of cMid1 in chick embryos and investigated if alterations in Mid1 protein function, specifically the ability of Mid1 to negatively regulate levels of protein phosphatase 2A (PP2A), affected CNC survival or migration. During the main phase of CNC migration (stage 9 to 11) cMid1 is strongly expressed within r2 and a subset of CNC in cranial mesenchyme at the level of r1/2 to the isthmus, but is not expressed in more caudal CNC streams. Inhibiting cMid1 function in r2 elevated PP2A levels. Overexpression of PP2A in r2 slowed CNC migration in vitro and in ovo and inhibited trigeminal gangliogenesis. Conversely in r4, forced expression of cMid1, or pharmacological inhibition of PP2A lowered PP2A levels. Inhibition of PP2A in r4 CNC in vitro up-regulated the disintegrin and metalloprotease ADAM10 and selectively increased CNC motility on fibronectin and collagen substrates, but not on laminin. In ovo, inhibiting PP2A activity in r4 increased CNC migration and hastened formation of the geniculate/vestibuloacoustic ganglion, comprising mostly epibranchial placode neuroblasts. Placodal neuroblast migration into the cranial mesenchyme is known to depend on the presence of r4 CNC and we show that inhibition of PP2A in r4 CNC causes premature breakdown of the epibranchial placode basement membrane and early immigration of placodal neuroblasts. In all cases, CNC proliferation and death were unaffected by altered PP2A levels. We propose that factors capable of altering PP2A activity, such as Mid1, affect CNC motility and matrix remodeling, thereby modulating craniofacial development.

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Craniofacial malformations: intrinsic vs extrinsic neural crest cell defects in Treacher Collins and 22q11 deletion syndromes

Cited by 50 publications

References 77 publications

Syndromes of the First and Second Branchial Arches, Part 1: Embryology and Characteristic Defects

Syndromes of the First and Second Branchial Arches, Part 1: Embryology and Characteristic Defects

Fate of cranial neural crest cells during craniofacial development in endothelin-A receptor-deficient mice

Regulation of PP2A activity by Mid1 controls cranial neural crest speed and gangliogenesis

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