Introduction Neural tube defects (NTD) are the consequence of a failure in the closure of the neural tube, and differ depending on their localization and extent. The term “neural tube defects” includes defects of the cranial vault, including the spectrum…
Introduction Destructive cerebral lesions are not embryonic malformations, but rather the result of an insult to a normally developed fetal brain. The most common causes are hemorrhage, hypoxia-ischemia, and infections, but the pathophysiology is unclear in many cases. The prognosis…
Introduction Holoprosencephaly (HPE) has been known since antiquity through the figure of the cyclopean shepherd Polyphemos in Homer's Odyssey (circa 800 bc ). Until the 17th century, a cyclopic newborn, whether it was a human or an animal, was associated…
Introduction Walker-Warburg syndrome (WWS) is a rare, lethal congenital diffuse neurodysplasia, characterized by variable ocular and cerebral abnormalities. Cerebral findings include ventriculomegaly, encephalocele, and Dandy-Walker malformation. Ocular findings are varied, may occur in the posterior or anterior segments of the…
Introduction The fetal cerebellum develops throughout pregnancy and may be visualized starting from the first trimester. By the seventh week of gestation, the rhombencephalic vesicle, the precursor of the fourth ventricle and cisterna magna, is the most prominent structure of…
Introduction Cortical neuronal cell development starts at about 7 weeks' gestation from stem cells in the germinal matrix that line the ventricles. The stem cells proliferate and differentiate into glial cells and neurons. The glial cells migrate radially to the…
Introduction Septooptic dysplasia (SOD), also known as de Morsier syndrome, is a rare heterogeneous disorder. It is characterized by optic nerve hypoplasia and midline forebrain abnormalities, such as agenesis of the corpus callosum, absence of the cavum septi pellucidi, and…
Introduction Anomalies of the corpus callosum and septum pellucidum are disorders of prosencephalic midline development. Midline prosencephalic development peaks at 7 to 12 weeks' gestation and includes the formation of the chiasmatic, commissural, and hypothalamic plates, enabling formation of the…
Introduction The choroid plexus is a vascular convolute, consisting of epithelial cells (a type of microglia), fenestrated blood vessels, and stroma, which lie in the ventricular system of the brain. It is the main source of cerebrospinal fluid (CSF) and…
Introduction The fetal spleen is an important center of hematopoiesis until the late fetal period. In postnatal life, the function of the spleen is mainly as an immune organ, with lymphocyte and monocyte production continuing throughout adult life. During fetal…