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Neuronal Migration Disorders
Neuronal migration disorder (NMD) refers to a heterogenous group of disorders that, it is supposed, share the same etiopathological mechanism: a variable degree of disruption in the migration of neuroblasts during neurogenesis. The neuronal migration disorders are termed cerebral dysgenesis disorders, brain malformations caused by primary alterations during neurogenesis; on the other hand, brain malformations are highly diverse and refer to any insult to the brain during its formation and maturation due to intrinsic or extrinsic causes that ultimately will alter the normal brain anatomy. However, there is some controversy in the terminology because virtually any malformation will involve neuroblast migration, either primarily or secondarily. Symptoms and signs Symptoms vary according to the abnormality, but often feature poor muscle tone and motor function, seizures, developmental delays, intellectual disabilities, failure to grow and thrive, difficulties with feeding, swelling ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lissencephaly
Lissencephaly (, meaning 'smooth brain') is a set of rare brain disorders whereby the whole or parts of the surface of the brain are smooth. It is caused by defective neuronal migration during the 12th to 24th weeks of gestation, resulting in a lack of development of brain folds (gyri) and grooves (sulci). It is a form of cephalic disorder. Terms such as ''agyria'' (no gyri) and '' pachygyria'' (broad gyri) are used to describe the appearance of the surface of the brain. Children with lissencephaly generally have significant developmental delays, but these vary greatly from child to child depending on the degree of brain malformation and seizure control. Life expectancy can be shortened, generally due to respiratory problems. Signs and symptoms Affected children display severe psychomotor impairment, failure to thrive, seizures, and muscle spasticity or hypotonia. Other symptoms of the disorder may include unusual facial appearance, difficulty swallowing, and anomalies of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pregnancy
Pregnancy is the time during which one or more offspring gestation, gestates inside a woman's uterus. A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Conception (biology), Conception usually occurs following sexual intercourse, vaginal intercourse, but can also occur through assisted reproductive technology procedures. A pregnancy may end in a Live birth (human), live birth, a miscarriage, an Abortion#Induced, induced abortion, or a stillbirth. Childbirth typically occurs around 40 weeks from the start of the Menstruation#Onset and frequency, last menstrual period (LMP), a span known as the Gestational age (obstetrics), ''gestational age''; this is just over nine months. Counting by Human fertilization#Fertilization age, ''fertilization age'', the length is about 38 weeks. Implantation (embryology), Implantation occurs on average 8–9 days after Human fertilization, fertilization. An ''embryo'' is the term for the deve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pachygyria
Pachygyria ( gyri) is a congenital malformation of the cerebral hemisphere. It results in unusually thick convolutions of the cerebral cortex. Typically, children have developmental delay and seizures, the onset and severity depending on the severity of the cortical malformation. Infantile spasms are common in affected children, as is intractable epilepsy. Presentation The term 'pachygyria' does not directly relate to a specific malformation but rather is used to generally describe physical characteristics of the brain in association with several neuronal migration disorders; most commonly disorders relating to varied degrees of lissencephaly. Lissencephaly is present in 1 of 85,470 births and the life span of those affected is short as only a few survive past the age of 20. Pachygyria is a condition identified by a type of cortical genetic malformation. Clinicians will subjectively determine the malformation based on the degree of malposition and the extent of thickened abno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porencephaly
Porencephaly is an extremely rare cephalic disorder involving encephalomalacia. It is a neurological disorder of the central nervous system characterized by cysts or Body cavity, cavities within the cerebral hemisphere.Parker, J. (2004). The official parent's sourcebook on porencephaly: A revised and updated directory for the internet age. ICON Health Publications. Porencephaly was termed by Heschl in 1859 to describe a cavity in the human brain. Derived from Greek language, Greek roots, the word ''porencephaly'' means 'holes in the brain'. The cysts and cavities (cystic brain lesions) are more likely to be the result of destructive (encephaloclastic) cause, but can also be from abnormal development (malformative), direct damage, inflammation, or hemorrhage. The cysts and cavities cause a wide range of physiological, physical, and neurological symptoms. Depending on the patient, this disorder may cause only minor neurological problems, without any disruption of intelligence, while ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schizencephaly
Schizencephaly () is a rare birth defect of the Human brain, brain, characterized by abnormal clefts lined with grey matter that form the ependyma of the cerebral ventricles to the pia mater. These clefts can occur bilaterally or unilaterally. Common clinical features of this malformation include epilepsy, motor deficits, and psychomotor retardation. Presentation Schizencephaly can be distinguished from porencephaly by the fact that in schizencephaly, the fluid-filled component is entirely lined by Heterotopia (medicine), heterotopic grey matter, while a porencephalic cyst is lined mostly by white matter. Individuals with clefts in both hemispheres, or bilateral clefts, are often developmentally delayed and have delayed speech and language skills and corticospinal dysfunction. Individuals with smaller, unilateral clefts (clefts in one hemisphere) may be weak or paralyzed on one side of the body and may have average or near-average intelligence. Patients with schizencephaly may al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microlissencephaly
Microlissencephaly (MLIS) is a rare congenital brain disorder that combines severe microcephaly (small head) with lissencephaly (smooth brain surface due to absent Sulcus (neuroanatomy), sulci and gyri). Microlissencephaly is a heterogeneous disorder, i.e. it has many different causes and a variable clinical course. Microlissencephaly is a malformation of cortical development (MCD) that occurs due to failure of neuronal migration between the third and fifth month of gestation as well as stem cell population abnormalities. Numerous genes have been found to be associated with microlissencephaly, however, the pathophysiology is still not completely understood. The combination of lissencephaly with severe congenital microcephaly is designated as microlissencephaly only when the Cerebral cortex, cortex is abnormally thick. If such combination exists with a normal cortical thickness (2.5 to 3 mm), it is known as "microcephaly with simplified gyral pattern" (MSGP). Both MLIS and MSGP ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lissencephaly
Lissencephaly (, meaning 'smooth brain') is a set of rare brain disorders whereby the whole or parts of the surface of the brain are smooth. It is caused by defective neuronal migration during the 12th to 24th weeks of gestation, resulting in a lack of development of brain folds (gyri) and grooves (sulci). It is a form of cephalic disorder. Terms such as ''agyria'' (no gyri) and '' pachygyria'' (broad gyri) are used to describe the appearance of the surface of the brain. Children with lissencephaly generally have significant developmental delays, but these vary greatly from child to child depending on the degree of brain malformation and seizure control. Life expectancy can be shortened, generally due to respiratory problems. Signs and symptoms Affected children display severe psychomotor impairment, failure to thrive, seizures, and muscle spasticity or hypotonia. Other symptoms of the disorder may include unusual facial appearance, difficulty swallowing, and anomalies of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Counseling
Genetic counseling is the process of investigating individuals and families affected by or at risk of genetic disorders to help them understand and adapt to the medical, psychological and familial implications of genetic contributions to disease. This field is considered necessary for the implementation of genomic medicine. The process integrates: * Interpretation of family and medical histories to assess the chance of disease occurrence or recurrence * Education about inheritance, testing, management, prevention, resources * Counseling to promote informed choices, adaptation to the risk or condition and support in reaching out to relatives that are also at risk History The practice of advising people about inherited traits began around the turn of the 20th century, shortly after William Bateson suggested that the new medical and biological study of heredity be called "genetics". Heredity became intertwined with social reforms when the field of modern eugenics took form. Although ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gyrus
In neuroanatomy, a gyrus (: gyri) is a ridge on the cerebral cortex. It is generally surrounded by one or more sulci (depressions or furrows; : sulcus). Gyri and sulci create the folded appearance of the brain in humans and other mammals. Structure The gyri are part of a system of folds and ridges that create a larger surface area for the human brain and other mammalian brains. Because the brain is confined to the skull, brain size is limited. Ridges and depressions create folds allowing a larger cortical surface area, and greater cognitive function, to exist in the confines of a smaller cranium. Development The human brain undergoes gyrification during fetal and neonatal development. In embryonic development, all mammalian brains begin as smooth structures derived from the neural tube. A cerebral cortex without surface convolutions is lissencephalic, meaning 'smooth-brained'. As development continues, gyri and sulci begin to take shape on the fetal brain, with deepe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cortical Layer
The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. It is the largest site of Neuron, neural integration in the central nervous system, and plays a key role in attention, perception, awareness, thought, memory, language, and consciousness. The six-layered neocortex makes up approximately 90% of the Cortex (anatomy), cortex, with the allocortex making up the remainder. The cortex is divided into left and right parts by the longitudinal fissure, which separates the two cerebral hemispheres that are joined beneath the cortex by the corpus callosum and other commissural fibers. In most mammals, apart from small mammals that have small brains, the cerebral cortex is folded, providing a greater surface area in the confined volume of the neurocranium, cranium. Apart from minimising brain and cranial volume, gyrification, cortical folding is crucial for the Neural circuit, brain circuitry ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
