What is angelmans syndrome

Is there an evolutionary origin for angelmans syndrome? or is it …?

http://answers.yahoo.com/question/index?qid=20081111184318AABfXGv

Angelman syndrome (AS) is a neuro-genetic disorder characterized by intellectual and developmental delay, sleep disturbance, seizures, jerky movements especially hand-flapping, frequent laughter or smiling, and usually a happy demeanour. AS…

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is there an evolutionary origin for angelmans syndrome? or is it just a genetic mutation?

Q: i need to make a poster with life expectancy, evolutionary origin and gene affected for angelmans syndrome….and i cant find too much information..please help

A: Angelman syndrome (AS) is a neuro-genetic disorder characterized by intellectual and developmental delay, sleep disturbance, seizures, jerky movements especially hand-flapping, frequent laughter or smiling, and usually a happy demeanour. AS is a classic example of genetic imprinting in that it is usually caused by deletion or inactivation of genes on the maternally inherited chromosome 15. The sister syndrome, Prader-Willi syndrome, is caused by a similar loss of paternally-inherited genes.AS is named after a British pediatrician, Dr. Harry Angelman, who first described the syndrome in 1965.[1] An older, alternative term for AS, happy puppet syndrome, is generally considered pejorative and stigmatizing so it is no longer used, though it remains useful as a diagnostic heuristic.People with AS are sometimes known as “Angels”, both because of the syndrome’s name and because of their youthful, happy appearance.Dr. Harry Angelman, a pediatrician working in Warrington (then in Lancashire) first reported three children with this condition in 1965.[1] He titled the paper “Puppet Children” and later explained that this was because of an oil painting he had seen:”I happened to see an oil painting…called… “Boy with a Puppet”. The boy’s laughing face and the fact that my patients exhibited jerky movements gave me the idea of writing an article about the three children with a title of Puppet Children.”[1] The condition was initially incorrectly presumed to be rare.In 1987, it was first noted that around half of the children with Angelman syndrome have a small piece of chromosome 15 missing (chromosome 15q partial deletion).Angelman syndrome is caused by the loss of the normal maternal contribution to a region of chromosome 15, most commonly by deletion of a segment of that chromosome. Other causes include uniparental disomy, translocation, or single gene mutation in that region. A healthy person receives two copies of chromosome 15, one from the mother, the other from the father. However, in the region of the chromosome that is critical for Angelman syndrome, the maternal and paternal contribution express certain genes very differently. This is due to sex-related epigenetic imprinting; the biochemical mechanism is DNA methylation. In a normal individual, the maternal allele is expressed and the paternal allele is silenced. If the maternal contribution is lost or mutated, the result is Angelman syndrome. (When the paternal contribution is lost, by similar mechanisms, the result is Prader-Willi syndrome.) Please note that the methylation test that is performed for Angelman syndrome (a defect in UBE3A) is actually looking for the gene’s neighbour SNRPN (which has the opposite pattern of methylation).[4]Angelman syndrome can also be the result of mutation of a single gene. This gene (UBE3A,[5] part of the ubiquitin pathway) is present on both the maternal and paternal chromosomes, but differs in the pattern of methylation (Imprinting). The paternal silencing of the UBE3A gene occurs in a brain region-specific manner; the maternal allele is active almost exclusively in the hippocampus and cerebellum. The most common genetic defect leading to Angelman syndrome is an ~4Mb (mega base) maternal deletion in chromosomal region 15q11-13 causing an absence of UBE3A expression in the maternally imprinted brain regions. UBE3A codes for an E6-AP ubiquitin ligase, which chooses its substrates very selectively and the four identified E6-AP substrates have shed little light on the possible molecular mechanisms underlying the human Angelman syndrome mental retardation state.Initial studies of mice that do not express maternal UBE3A show severe impairments in hippocampal memory formation. Most notably, there is a deficit in a learning paradigm that involves hippocampus-dependent contextual fear conditioning. In addition, maintenance of long-term synaptic plasticity in hippocampal area CA1 in vitro is disrupted in Ube3a-/- mice. These results provide links amongst hippocampal synaptic plasticity in vitro, formation of hippocampus-dependent memory in vitro, and the molecular pathology of Angelman syndrome.Feeding problems during infancy (poor suck and poor weight gain) in 75% Delay in sitting and walking Absent or little speech (not in all cases – some children have a vocabulary of up to 50 words) Receptive and non-verbal communication skills higher than verbal ones Poor attention span and hyperactivity Severe learning disabilities Epilepsy (80%) and an abnormal EEG Unusual movements (fine tremors, hand flapping, jerking movements) Affectionate nature and frequent inappropriate laughter Wide-based stiff-legged gait, with tendency to hold arms up and flexed while walking. Below average head size, often with flattening at the back Subtle, but sometimes characteristic facial features (wide mouth, widely spaced teeth, prominent chin, tendency to tongue thrust) Poor sleeping patte

angelmans syndrome/ what are the symtoms?

Q: Do pediatricians have difficulty diagnosing this condition.How early is the disease found in children?

A: http://www.angelman.org/http://en.wikipedia.org/wiki/Angelman_Syndrome

are there any people you or someone you know have angelmans syndrome?

Q:

A: What is angelmans syndrome?