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Megalencephaly
Megalencephaly (or macrencephaly; abbreviated MEG) is a growth development disorder in which the brain is abnormally large. It is characterized by a brain with an average weight that is 2.5 standard deviations above the mean of the general population. Approximately 1 out of 50 children (2%) are said to have the characteristics of megalencephaly in the general population. A mutation in the PI3K-AKT pathway is believed to be the primary cause of brain proliferation and ultimately the root cause of megalencephaly. This mutation has produced a classification of brain overdevelopment that consists of two syndromes including megalencephaly-capillary malformation (MCAP) and megalencephaly-polydactyly- polymicrogyria-hydrocephalus (MPPH). Megalencephaly is usually diagnosed at birth and is confirmed with an MRI. There are several neuropsychiatric disorders linked with megalencephaly; however, studies have shown that autism is the most prevalent association with the malformation of MEG ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrocephaly
Macrocephaly is a condition in which circumference of the human head is abnormally large. It may be pathological or harmless, and can be a familial genetic characteristic. People diagnosed with macrocephaly will receive further medical tests to determine whether the syndrome is accompanied by particular disorders. Those with benign or familial macrocephaly are considered to have megalencephaly. Causes Many people with abnormally large heads or large skulls are healthy, but macrocephaly may be pathological. Pathologic macrocephaly may be due to megalencephaly (enlarged brain), hydrocephalus (abnormally increased cerebrospinal fluid), cranial hyperostosis (bone overgrowth), and other conditions. Pathologic macrocephaly is called "syndromic", when it is associated with any other noteworthy condition, and "nonsyndromic" otherwise. Pathologic macrocephaly may be caused by congenital anatomic abnormalities, genetic conditions, or by environmental events. Many genetic conditions ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megalencephaly-capillary Malformation
Macrocephaly-capillary malformation (M-CM) is a multiple malformation syndrome causing abnormal body and head overgrowth and cutaneous, vascular, neurologic, and limb abnormalities. Though not every patient has all features, commonly found signs include macrocephaly, congenital macrosomia, extensive cutaneous capillary malformation (naevus flammeus or port-wine stain type birthmark over much of the body; a capillary malformation of the upper lip or philtrum is seen in many patients with this condition), body asymmetry (also called hemihyperplasia or hemihypertrophy), polydactyly or syndactyly of the hands and feet, lax joints, doughy skin, variable developmental delay and other neurologic problems such as seizures and low muscle tone. Genetics Mosaic mutations in PIK3CA have been found to be the genetic cause of M-CM. Other overgrowth conditions with distinct phenotypes have also been found to be caused by mosaic mutations in PIK3CA. How different mutations in this gene result ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrocephalus
Hydrocephalus is a condition in which an accumulation of cerebrospinal fluid (CSF) occurs within the brain. This typically causes increased pressure inside the skull. Older people may have headaches, double vision, poor balance, urinary incontinence, personality changes, or mental impairment. In babies, it may be seen as a rapid increase in head size. Other symptoms may include vomiting, sleepiness, seizures, and downward pointing of the eyes. Hydrocephalus can occur due to birth defects or be acquired later in life. Associated birth defects include neural tube defects and those that result in aqueductal stenosis. Other causes include meningitis, brain tumors, traumatic brain injury, intraventricular hemorrhage, and subarachnoid hemorrhage. The four types of hydrocephalus are communicating, noncommunicating, ''ex vacuo'', and normal pressure. Diagnosis is typically made by physical examination and medical imaging. Hydrocephalus is typically treated by the surg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Kinase B
Protein kinase B (PKB), also known as Akt, is the collective name of a set of three serine/threonine-specific protein kinases that play key roles in multiple cellular processes such as glucose metabolism, apoptosis, cell proliferation, transcription, and cell migration. Family members - Isoforms There are three different genes that encode isoforms of Protein kinase B. These three genes are referred to as AKT1, AKT2, and AKT3 and encode the RAC alpha, beta, and gamma serine/threonine protein kinases respectively. The terms PKB and Akt may refer to the products of all three genes collectively, but sometimes are used to refer to PKB alpha and Akt1 alone. Akt1 is involved in cellular survival pathways, by inhibiting apoptotic processes. Akt1 is also able to induce protein synthesis pathways, and is therefore a key signaling protein in the cellular pathways that lead to skeletal muscle hypertrophy and general tissue growth. A mouse model with complete deletion of the Akt1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphoinositide 3-kinase
Phosphoinositide 3-kinases (PI3Ks), also called phosphatidylinositol 3-kinases, are a family of enzymes involved in cellular functions such as cell growth, proliferation, differentiation, motility, survival and intracellular trafficking, which in turn are involved in cancer. PI3Ks are a family of related intracellular signal transducer enzymes capable of phosphorylating the 3 position hydroxyl group of the inositol ring of phosphatidylinositol (PtdIns). The pathway, with oncogene PIK3CA and tumor suppressor gene PTEN, is implicated in the sensitivity of cancer tumors to insulin and IGF1, and in calorie restriction. Discovery The discovery of PI3Ks by Lewis Cantley and colleagues began with their identification of a previously unknown phosphoinositide kinase associated with the polyoma middle T protein. They observed unique substrate specificity and chromatographic properties of the products of the lipid kinase, leading to the discovery that this phosphoinositide kinase had ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidermal Nevus Syndrome
Epidermal nevus syndrome (also known as "Feuerstein and Mims syndrome", and "Solomon's syndrome"Freedberg, et al. (2003). ''Fitzpatrick's Dermatology in General Medicine''. (6th ed.). McGraw-Hill. .) is a rare disease that was first described in 1968 and consists of extensive epidermal nevi with abnormalities of the central nervous system (CNS), skeleton, skin, cardiovascular system, genitourinary system and eyes.James, William; Berger, Timothy; Elston, Dirk (2005). ''Andrews' Diseases of the Skin: Clinical Dermatology''. (10th ed.). Saunders. . However, since the syndrome's first description, a broader concept for the "epidermal nevus" syndrome has been proposed, with at least six types being described:Happle, R. "Epidermal nevus syndrome." ''Semin Dermatol''. 1995;14:111. :* Schimmelpenning syndrome :* Nevus comedonicus syndrome :* Pigmented hairy epidermal nevus syndrome :* Proteus syndrome :* CHILD syndrome :* Phakomatosis pigmentokeratotica See also * Epidermis * List ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Klippel–Trénaunay Syndrome
Klippel–Trénaunay syndrome, formerly Klippel–Trénaunay–Weber syndrome and sometimes angioosteohypertrophy syndrome and hemangiectatic hypertrophy, is a rare congenital medical condition in which blood vessels and/or lymph vessels fail to form properly. The three main features are nevus flammeus (port-wine stain), venous and lymphatic malformations, and soft-tissue hypertrophy of the affected limb. It is similar to, though distinctly separate from, the less common Parkes Weber syndrome. The classical triad of Klippel–Trenaunay syndrome consists of: # vascular malformations of the capillary, venous and lymphatic vessels; # varicosities of unusual distribution, particularly the lateral venous anomaly; and # unilateral soft and skeletal tissue hypertrophy, usually the lower extremity. Signs and symptoms The birth defect is diagnosed by the presence of a combination of these symptoms (often on approximately of the body, though some cases may present more or less affected ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuberous Sclerosis
Tuberous sclerosis complex (TSC) is a rare multisystem autosomal dominant genetic disease that causes non-cancerous tumours to grow in the brain and on other vital organs such as the kidneys, heart, liver, eyes, lungs and skin. A combination of symptoms may include seizures, intellectual disability, developmental delay, behavioral problems, skin abnormalities, lung disease, and kidney disease. TSC is caused by a mutation of either of two genes, '' TSC1'' and '' TSC2'', which code for the proteins hamartin and tuberin, respectively, with ''TSC2'' mutations accounting for the majority and tending to cause more severe symptoms. These proteins act as tumor growth suppressors, agents that regulate cell proliferation and differentiation. Prognosis is highly variable and depends on the symptoms, but life expectancy is normal for many. The prevalence of the disease is estimated to be 7 to 12 in 100,000. The disease is often abbreviated to tuberous sclerosis, which refers to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beckwith–Wiedemann Syndrome
Beckwith–Wiedemann syndrome (; abbreviated BWS) is an overgrowth disorder usually present at birth, characterized by an increased risk of childhood cancer and certain congenital features. A minority (97th centile) * Macroglossia * Hemihyperplasia (asymmetric overgrowth of one or more regions of the body) * Omphalocele (also called exomphalos) or umbilical hernia * Embryonal tumor (e.g., Wilms tumor, hepatoblastoma, neuroblastoma, rhabdomyosarcoma) in childhood * Visceromegaly involving one or more intra-abdominal organs including liver, spleen, kidneys, adrenal glands, and/or pancreas * Cytomegaly of the fetal adrenal cortex (pathognomonic) * Renal abnormalities including structural abnormalities, nephromegaly, nephrocalcinosis, and/or later development of medullary sponge kidney * Anterior linear ear lobe creases and/or posterior helical ear pits * Placental mesenchymal dysplasia * Cleft palate (rare in BWS) * Cardiomyopathy (rare in BWS) * Positive family history (≥1 famil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Achondroplasia
Achondroplasia is a genetic disorder with an autosomal dominant pattern of inheritance whose primary feature is dwarfism. In those with the condition, the arms and legs are short, while the torso is typically of normal length. Those affected have an average adult height of for males and for females. Other features can include an enlarged head and prominent forehead. Complications can include sleep apnea or recurrent ear infections. Achondroplasia includes short-limb skeletal dysplasia with severe combined immunodeficiency. Achondroplasia is caused by a mutation in the fibroblast growth factor receptor 3 (''FGFR3'') gene that results in its protein being overactive. Achondroplasia results in impaired endochondral bone growth (bone growth within cartilage). The disorder has an autosomal dominant mode of inheritance, meaning only one mutated copy of the gene is required for the condition to occur. About 80% of cases occur in children of parents of average stature and resul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
