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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] |
Macrocephaly-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 res ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Cowden Disease
Cowden syndrome (also known as Cowden's disease and multiple hamartoma syndrome) is an autosomal dominant inherited condition characterized by benign overgrowths called hamartomas as well as an increased lifetime risk of breast, thyroid, uterine, and other cancers. It is often underdiagnosed due to variability in disease presentation, but 99% of patients report mucocutaneous symptoms by age 20–29. Despite some considering it a primarily dermatologic condition, Cowden's syndrome is a multi-system disorder that also includes neurodevelopmental disorders such as macrocephaly. The incidence of Cowden's disease is about 1 in 200,000, making it quite rare. Furthermore, early and continuous screening is essential in the management of this disorder to prevent malignancies. It is associated with mutations in PTEN on 10q23.3, a tumor suppressor gene otherwise known as phosphatase and tensin homolog, that results in dysregulation of the mTOR pathway leading to errors in cell proliferation, ... [...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] |
Autism
The autism spectrum, often referred to as just autism or in the context of a professional diagnosis autism spectrum disorder (ASD) or autism spectrum condition (ASC), is a neurodevelopmental condition (or conditions) characterized by difficulties in social interaction, verbal and nonverbal communication, and the presence of repetitive behavior and restricted interests. Other common signs include unusual responses to sensory stimuli. Autism is generally understood as a '' spectrum disorder'', which means that it can manifest differently in each person: any given autistic individual is likely to show some, but not all, of the characteristics associated with it, and the person may exhibit them to varying degrees. Some autistic people remain nonspeaking over the course of their lifespan, while others have relatively unimpaired spoken language. There is large variation in the level of support people require, and the same person may present differently at varying times. Historical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weaver Syndrome
Weaver syndrome is a rare autosomal dominant genetic disorder associated with rapid growth beginning in the prenatal period and continuing through the toddler and youth years. It is characterized by advanced osseous maturation and distinctive craniofacial, skeletal and neurological abnormalities. It is similar to Sotos syndrome and is classified as an overgrowth syndrome. Its genetic cause was identified in 2011 as mutations in the '' EZH2'' gene. Forty-eight cases had been documented and confirmed , and its prevalence is estimated to be similar to that of Sotos syndrome, around 1 in 15,000. It was first described by American physician David Weaver in 1974. Signs and symptoms Children with Weaver syndrome tend to look similar and have distinctive physical and craniofacial characteristics, which may include several, but not all, of the following features: * Macrocephaly * Large bifrontal diameter * Flattened occiput * Long philtrum * Retrognathia * Round face in infancy * Pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sotos Syndrome
Sotos syndrome is a rare genetic disorder characterized by excessive physical growth during the first years of life. Excessive growth often starts in infancy and continues into the early teen years. The disorder may be accompanied by autism, mild intellectual disability, delayed motor, cognitive, and social development, hypotonia (low muscle tone), and speech impairments. Children with Sotos syndrome tend to be large at birth and are often taller, heavier, and have relatively large skulls (macrocephaly) than is normal for their age. Signs of the disorder, which vary among individuals, include a disproportionately large skull with a slightly protrusive forehead, large hands and feet, large mandible, hypertelorism (an abnormally increased distance between the eyes), and downslanting eyes. Clumsiness, an awkward gait, and unusual aggressiveness or irritability may also occur. Although most cases of Sotos syndrome occur sporadically, familial cases have also been reported. It is simi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Head
In human anatomy, the head is at the top of the human body. It supports the face and is maintained by the skull, which itself encloses the brain. Structure The human head consists of a fleshy outer portion, which surrounds the bony skull. The brain is enclosed within the skull. There are 22 bones in the human head. The head rests on the neck, and the seven cervical vertebrae support it. The human head typically weighs between Over 98% of humans fit into this range. There have been odd incidences where human beings have abnormally small or large heads. The Zika virus was responsible for underdeveloped heads in the early 2000s. The face is the anterior part of the head, containing the eyes, nose, and mouth. On either side of the mouth, the cheeks provide a fleshy border to the oral cavity. The ears sit to either side of the head. Blood supply The head receives blood supply through the internal and external carotid arteries. These supply the area outside of the skul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PTEN (gene)
Phosphatase and tensin homolog (PTEN) is a phosphatase in humans and is encoded by the ''PTEN'' gene. Mutations of this gene are a step in the development of many cancers, specifically glioblastoma, lung cancer, breast cancer, and prostate cancer. Genes corresponding to PTEN (orthologs) have been identified in most mammals for which complete genome data are available. ''PTEN'' acts as a tumor suppressor gene through the action of its phosphatase protein product. This phosphatase is involved in the regulation of the cell cycle, preventing cells from growing and dividing too rapidly. It is a target of many anticancer drugs. The protein encoded by this gene is a phosphatidylinositol-3,4,5-trisphosphate 3-phosphatase. It contains a TNS1, tensin-like domain as well as a catalytic domain similar to that of the dual specificity protein tyrosine phosphatases. Unlike most of the protein tyrosine phosphatases, this protein preferentially dephosphorylates phosphoinositide substrates. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megalencephalic Leukoencephalopathy With Subcortical Cysts
Megalencephalic leukoencephalopathy with subcortical cysts (MLC, or Van der Knaap disease) is a form of hereditary CNS demyelinating disease. It belongs to a group of disorders called leukodystrophies. It is characterized by early-onset enlargement of the head (macrocephaly) as well as delayed-onset neurological deterioration to include spasticity, epilepsy, and lack of muscular coordination. MLC does not appear to be a disease that is fatal at birth or early in life despite its symptoms, although the number of patients throughout history known to have the disease is fairly limited. It belongs to a group of disorders called leukodystrophies. A series of cases with megalencephalic leukodystrophy were described by the Indian neurologist Bhim Sen Singhal (1933-) in 1991. However, it is sometimes referred to as Van der Knaap disease after the Dutch neurologist Marjo van der Knaap who described another series of cases with clinical and radiological features in 1995. There are three t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
