Neurocristopathies: Enigmatic Appearances of Neural Crest Cell-derived Abnormalities.

The neural crest is an important transient structure that develops during embryogenesis in vertebrates. Neural crest cells are multipotent progenitor cells that migrate and develop into a diverse range of cells and tissues throughout the body. Although neural crest cells originate from the ectoderm, they can differentiate into mesodermal-type or endodermal-type cells and tissues. Some of these tissues include the peripheral, autonomic, and enteric nervous systems; chromaffin cells of the adrenal medulla; smooth muscles of the intracranial blood vessels; melanocytes of the skin; cartilage and bones of the face; and parafollicular cells of the thyroid gland. Neurocristopathies are a group of diseases caused by the abnormal generation, migration, or differentiation of neural crest cells. They often involve multiple organ systems in a single person, are often familial, and can be associated with the development of neoplasms. As understanding of the neural crest has advanced, many seemingly disparate diseases, such Treacher Collins syndrome, 22q11.2 deletion syndrome, Hirschsprung disease, neuroblastoma, neurocutaneous melanocytosis, and neurofibromatosis, have come to be recognized as neurocristopathies. Neurocristopathies can be divided into three main categories: dysgenetic malformations, neoplasms, and combined dysgenetic and neoplastic syndromes. In this article, neural crest development, as well as several associated dysgenetic, neoplastic, and combined neurocristopathies, are reviewed. Neurocristopathies often have clinical manifestations in multiple organ systems, and radiologists are positioned to have significant roles in the initial diagnosis of these disorders, evaluation of subclinical associated lesions, creation of treatment plans, and patient follow-up. Online supplemental material is available for this article. ©RSNA, 2019.

PHACE syndrome--clinical features, aetiology and management.

UNLABELLED: PHACE syndrome comprises a spectrum of anomalies including posterior fossa malformations, haemangioma, arterial anomalies, cardiac defects and eye anomalies. PHACE should be considered in any patient with a large facial segmental infantile haemangioma (IH), and multidisciplinary management is crucial. Low-dose propranolol is effectively for the treatment of IH associated with PHACE syndrome. Recent evidence suggests IH is comprised of mesoderm-derived haemogenic endothelium. CONCLUSION: The embryonic developmental anomaly nature of IH provides an insight into the origin of PHACE syndrome.

PHACE syndrome: current knowledge, future directions.

On November 7-8, 2008, physicians gathered in Houston Texas for the first-ever workshop on PHACE syndrome, an important and recently described neurocutaneous syndrome. This article represents a summary of the discussions held at that workshop, which was attended by a broad range of medical specialists.

[Progress in pediatric neurology]. / Progrès en neurologie pédiatrique.

A central part of Pediatric Neurology is currently dominated by the search for genetic factors involved in developmental disorders of the nervous system, including cases where the cytogenetic examination remains uncontributive. The prerequisite for a good definition of the malformative phenotypes leads to distinguish: 1 cerebral malformations that can be identified at the macroscopic scale, by imaging. 2 polymalformative syndromes including mental retardation where cerebral imaging is not contributive, thus the syndromatic definition is based on associated somatic anomalies. 3 Non-syndromatic mental retardation, where a genetic origin is clear only in the familial forms. Various methodological approaches have included genetic linkage studies, search for inframicroscopic chromosomal rearrangements in the critical region and investigation of candidate genes. A great number of syndromes have been connected with a great diversity of genetic mechanisms, whose many examples are presented: genopathies with regular or variable expression, unstable mutations, contiguous gene syndromes or other complex infracytogenetic rearrangements, chromosomal or genic mosaicisms, mutations submitted to parental imprinting. New methods of genomic screening will be necessary to progress in this field, given the great number of genes involved in cerebral development. As for the early developmental disorders of the PNS and muscle, their diagnosis becomes frequent during the intrauterine life, raising the problem of a better definition of the fetopathological phenotypes.

Loss of cell polarity causes severe brain dysplasia in Lgl1 knockout mice.

Disruption of cell polarity is seen in many cancers; however, it is generally considered a late event in tumor progression. Lethal giant larvae (Lgl) has been implicated in maintenance of cell polarity in Drosophila and cultured mammalian cells. We now show that loss of Lgl1 in mice results in formation of neuroepithelial rosette-like structures, similar to the neuroblastic rosettes in human primitive neuroectodermal tumors. The newborn Lgl1(-/-) pups develop severe hydrocephalus and die neonatally. A large proportion of Lgl1(-/-) neural progenitor cells fail to exit the cell cycle and differentiate, and, instead, continue to proliferate and die by apoptosis. Dividing Lgl1(-/-) cells are unable to asymmetrically localize the Notch inhibitor Numb, and the resulting failure of asymmetric cell divisions may be responsible for the hyperproliferation and the lack of differentiation. These results reveal a critical role for mammalian Lgl1 in regulating of proliferation, differentiation, and tissue organization and demonstrate a potential causative role of disruption of cell polarity in neoplastic transformation of neuroepithelial cells.