Skin Development and Disease: A Molecular Perspective.

Skin, the largest organ in the human body, is a crucial protective barrier that plays essential roles in thermoregulation, sensation, and immune defence. This complex organ undergoes intricate processes of development. Skin development initiates during the embryonic stage, orchestrated by molecular cues that control epidermal specification, commitment, stratification, terminal differentiation, and appendage growth. Key signalling pathways are integral in coordinating the development of the epidermis, hair follicles, and sweat glands. The complex interplay among these pathways is vital for the appropriate formation and functionality of the skin. Disruptions in multiple molecular pathways can give rise to a spectrum of skin diseases, from congenital skin disorders to cancers. By delving into the molecular mechanisms implicated in developmental processes, as well as in the pathogenesis of diseases, this narrative review aims to present a comprehensive understanding of these aspects. Such knowledge paves the way for developing innovative targeted therapies and personalised treatment approaches for various skin conditions.

Genetic Identity of Neural Crest Cell Differentiation in Tissue and Organ Development.

The neural crest (NC), also known as the "fourth germ layer", is an embryonic structure with important contributions to multiple tissue and organ systems. Neural crest cells (NCCs) are subjected to epithelial to mesenchymal transition and migrate throughout the embryo until they reach their destinations, where they differentiate into discrete cell types. Specific gene expression enables this precise NCCs delamination and colonization potency in distinct and diverse locations therein. This review aims to summarize the current experimental evidence from multiple species into the NCCs specifier genes that drive this embryo body axes segmentation. Additionally, it attempts to filter further into the genetic background that produces these individual cell subpopulations. Understanding the multifaceted genetic makeup that shapes NC-related embryonic structures will offer valuable insights to researchers studying organogenesis and disease phenotypes arising from dysmorphogenesis.

Clinical and Genetic Correlation in Neurocristopathies: Bridging a Precision Medicine Gap.

Neurocristopathies (NCPs) encompass a spectrum of disorders arising from issues during the formation and migration of neural crest cells (NCCs). NCCs undergo epithelial-mesenchymal transition (EMT) and upon key developmental gene deregulation, fetuses and neonates are prone to exhibit diverse manifestations depending on the affected area. These conditions are generally rare and often have a genetic basis, with many following Mendelian inheritance patterns, thus making them perfect candidates for precision medicine. Examples include cranial NCPs, like Goldenhar syndrome and Axenfeld-Rieger syndrome; cardiac-vagal NCPs, such as DiGeorge syndrome; truncal NCPs, like congenital central hypoventilation syndrome and Waardenburg syndrome; and enteric NCPs, such as Hirschsprung disease. Additionally, NCCs' migratory and differentiating nature makes their derivatives prone to tumors, with various cancer types categorized based on their NCC origin. Representative examples include schwannomas and pheochromocytomas. This review summarizes current knowledge of diseases arising from defects in NCCs' specification and highlights the potential of precision medicine to remedy a clinical phenotype by targeting the genotype, particularly important given that those affected are primarily infants and young children.