scholarly journals Aberrant early growth of individual trigeminal sensory and motor axons in a series of mouse genetic models of 22q11.2 deletion syndrome

2020 ◽  
Vol 29 (18) ◽  
pp. 3081-3093
Author(s):  
Zahra Motahari ◽  
Thomas M Maynard ◽  
Anastas Popratiloff ◽  
Sally A Moody ◽  
Anthony-S LaMantia
Keyword(s):  
Developmental Disorders ◽  
Axon Growth ◽  
22Q11.2 Deletion Syndrome ◽  
Deletion Syndrome ◽  
Motor Axons ◽  
22Q11.2 Deletion ◽  
Critical Determinant ◽  
Sensory Axons ◽  
Anterior Posterior

Abstract We identified divergent modes of initial axon growth that prefigure disrupted differentiation of the trigeminal nerve (CN V), a cranial nerve essential for suckling, feeding and swallowing (S/F/S), a key innate behavior compromised in multiple genetic developmental disorders including DiGeorge/22q11.2 Deletion Syndrome (22q11.2 DS). We combined rapid in vivo labeling of single CN V axons in LgDel+/− mouse embryos, a genomically accurate 22q11.2DS model, and 3D imaging to identify and quantify phenotypes that could not be resolved using existing methods. We assessed these phenotypes in three 22q11.2-related genotypes to determine whether individual CN V motor and sensory axons wander, branch and sprout aberrantly in register with altered anterior–posterior hindbrain patterning and gross morphological disruption of CN V seen in LgDel+/−. In the additional 22q11.2-related genotypes: Tbx1+/−, Ranbp1−/−, Ranbp1+/− and LgDel+/−:Raldh2+/−; axon phenotypes are seen when hindbrain patterning and CN V gross morphology is altered, but not when it is normal or restored toward WT. This disordered growth of CN V sensory and motor axons, whose appropriate targeting is critical for optimal S/F/S, may be an early, critical determinant of imprecise innervation leading to inefficient oropharyngeal function associated with 22q11.2 deletion from birth onward.

scholarly journals The 22q11.2 Deletion Syndrome: A Gene Dosage Perspective

2006 ◽  
Vol 6 ◽  
pp. 1881-1887 ◽  
Author(s):  
Antonio Baldini
Keyword(s):  
Developmental Stages ◽  
Gene Dosage ◽  
Single Gene ◽  
22Q11.2 Deletion Syndrome ◽  
Genomic Region ◽  
Deletion Syndrome ◽  
Genomic Disorder ◽  
22Q11.2 Deletion ◽  
Developmental Context

The 22q11.2 deletion/DiGeorge syndrome is a relatively common “genomic” disorder that results from heterozygous deletion of a 3-Mbp segment of chromosome 22. Of the more than 30 genes deleted in this syndrome,TBX1is the only one that has been found to be mutated in some patients with a phenotype that is very similar to that of patients with the full deletion, suggesting thatTBX1haploinsufficiency is a major contributor to the syndrome’s phenotype. Multi- and single-gene mouse models have provided a considerable amount of information about the consequences of decreased and increased dosage of the genomic region (and in particular of theTbx1gene) on mouse embryonic development. Modified alleles ofTbx1, as well as conditional ablation strategies have been utilized to mapin vivothe tissues and developmental stages most sensitive to gene dosage. These experiments have revealed substantially different sensitivity to gene dosage in different tissues and at different times, underlying the importance of the developmental context within which gene dosage reduction occurs.

scholarly journals In vivo evidence of microstructural hypo-connectivity of brain white matter in 22q11.2 deletion syndrome

2020 ◽  
Author(s):  
Erika Raven ◽  
Jelle Veraart ◽  
Rogier Kievit ◽  
Sila Genc ◽  
Isobel Ward ◽  
...  
Keyword(s):  
White Matter ◽  
Large Scale ◽  
22Q11.2 Deletion Syndrome ◽  
Deletion Syndrome ◽  
Typically Developing ◽  
22Q11.2 Deletion ◽  
Genetic Syndrome ◽  
Brain White Matter ◽  
Axonal Morphology

Abstract 22q11.2 Deletion Syndrome, or 22q11.2DS, is a genetic syndrome associated with high rates of schizophrenia, autism, and attention deficit hyperactivity disorder, in addition to widespread structural and functional abnormalities throughout the brain. Experimental animal models have identified neuronal connectivity deficits, e.g., decreased axonal length and complexity of axonal branching, as a primary mechanism underlying atypical brain development in 22q11.2DS. However, it is still unclear whether deficits in axonal morphology can also be observed in people with 22q11.2DS. Here, we provide an unparalleled in vivo characterisation of white matter microstructure in both typically-developing children and children with 22q11.2DS using a dedicated magnetic resonance imaging scanner which is sensitive to axonal morphology. By extracting a rich array of diffusion metrics, we present microstructural profiles of typical and atypical white matter development, and provide new evidence of connectivity differences between typically-developing and 22q11.2DS children. A recent, large-scale consortium study identified higher diffusion anisotropy and reduced overall mobility of water as hallmark microstructural alterations of white matter in 22q11.2DS, in particular for commissural fibers. We observed similar findings across all white matter tracts in this study, in addition to identifying deficits in axonal morphology. This, in combination with reduced tract volume measurements, supports the hypothesis that microstructural connectivity in 22q11.2DS is mediated by densely packed axons with disproportionately small diameters. Our findings provide insight into the in vivo mechanistic features of 22q11.2DS, and promote further investigation of shared features in neurodevelopmental and psychiatric disorders.

Surgical Management of Patients With 22q11.2 Deletion Syndrome

2019 ◽  
Vol 4 (5) ◽  
pp. 857-869
Author(s):  
Oksana A. Jackson ◽  
Alison E. Kaye
Keyword(s):  
Surgical Management ◽  
Preoperative Evaluation ◽  
Preoperative Assessment ◽  
22Q11.2 Deletion Syndrome ◽  
Deletion Syndrome ◽  
22Q11.2 Deletion ◽  
Surgical Decision ◽  
Obstructive Sleep ◽  
Spine Abnormalities ◽  
Speech Assessment

Purpose The purpose of this tutorial was to describe the surgical management of palate-related abnormalities associated with 22q11.2 deletion syndrome. Craniofacial differences in 22q11.2 deletion syndrome may include overt or occult clefting of the palate and/or lip along with oropharyngeal variances that may lead to velopharyngeal dysfunction. This chapter will describe these circumstances, including incidence, diagnosis, and indications for surgical intervention. Speech assessment and imaging of the velopharyngeal system will be discussed as it relates to preoperative evaluation and surgical decision making. Important for patients with 22q11.2 deletion syndrome is appropriate preoperative screening to assess for internal carotid artery positioning, cervical spine abnormalities, and obstructive sleep apnea. Timing of surgery as well as different techniques, common complications, and outcomes will also be discussed. Conclusion Management of velopharyngeal dysfunction in patients with 22q11.2 deletion syndrome is challenging and requires thoughtful preoperative assessment and planning as well as a careful surgical technique.

Psychosocial Risks and Management for Children and Adolescents With 22q11.2 Deletion Syndrome

2019 ◽  
Vol 4 (4) ◽  
pp. 633-640 ◽  
Author(s):  
Canice E. Crerand ◽  
Ari N. Rabkin
Keyword(s):  
Cognitive Abilities ◽  
Psychotic Disorders ◽  
Developmental Stages ◽  
Early Adulthood ◽  
22Q11.2 Deletion Syndrome ◽  
Deletion Syndrome ◽  
22Q11.2 Deletion ◽  
Psychosocial Risks ◽  
Empirically Supported ◽  
Specific Education

Purpose This article reviews the psychosocial risks associated with 22q11.2 deletion syndrome, a relatively common genetic condition associated with a range of physical and psychiatric problems. Risks associated with developmental stages from infancy through adolescence and early adulthood are described, including developmental, learning, and intellectual disabilities as well as psychiatric disorders including anxiety, mood, and psychotic disorders. Other risks related to coping with health problems and related treatments are also detailed for both affected individuals and their families. Conclusion The article ends with strategies for addressing psychosocial risks including provision of condition-specific education, enhancement of social support, routine assessment of cognitive abilities, regular mental health screening, and referrals for empirically supported psychiatric and psychological treatments.

Conotruncal heart defects and aortic arch anomalies in fetuses with 22q11.2 deletion syndrome

2020 ◽  
Author(s):  
I.V. Novikova, O.M. Khurs, T.V. Demidovich et all
Keyword(s):  
Aortic Arch ◽  
Heart Defects ◽  
22Q11.2 Deletion Syndrome ◽  
Ventricular Outflow Tract ◽  
Double Outlet Right Ventricle ◽  
Interrupted Aortic Arch ◽  
Left Ventricular ◽  
Deletion Syndrome ◽  
22Q11.2 Deletion ◽  
Aortic Arch Anomalies

16 second trimester fetuses with 22q11.2 deletion syndrome have been examined at anatomic-pathological investigation. Main cardiovascular diseases were ascending aorta hypoplasia with aortic valve stenosis (n = 6; 37.5%), truncus arteriosus (n = 5; 31.25%), tetralogy of Fallot (n = 3; 18.75%) and double-outlet right ventricle (n = 1; 6.25%). Ventricular septal defect was present in 16 cases. Associated aortic arch anomalies included interrupted aortic arch (n = 9; 56.25%), right aortic arch (n = 6; 37.5%), retroesophageal ring (n = 1; 6.25%) and aberrant right subclavian arteria (n = 5; 31.25%). 5 fetuses had left ventricular outflow tract obstructive lesions with interrupted aortic arch of type B combined with aberrant right subclavian arteria.

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