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Occurs when a person receives two copies of a chromosome, or of part of a chromosome, from one parent and no copies from the other parent.
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What is the meaning of uniparental disomy?
Uniparental disomy is a chromosome abnormality where a pair of chromosomes only have DNA from one parent and are miss DNA from the other parent. This abnormality happens during mitosis.
What has the author Eric Engel written?
Eric Engel has written: 'Genomic imprinting and uniparental disomy in medicine' -- subject(s): Chromosome abnormalities, Genetic disorders, Genomic imprinting
How is angelman syndrome inherited?
A defect on maternal chromosome 15 will cause the sundrome. Since the paternal copy, which is most likely normal is silenced, it makes no difference. Uniparental disomy will also result in the syndrome.
Is angel-man syndrome sex-linked?
No. However, if the maternal copy of chromosome 15 has a mutation on a specific gene, angelman's results. Also, getting two copies of chromosome 15 from the father results in angelman's (Paternal uniparental disomy).
How is angel man's symptom inherited?
Most cases of Angelman syndrome are not inherited, particularly those caused by a deletion in the maternal chromosome 15 or by paternal uniparental disomy. These genetic changes occur as random events during the formation of reproductive cells (eggs and sperm) or in early embryonic development. Affected people typically have no history of the disorder in their family.
How is the prader-willi syndrome gene dominant?
Prader-Willi Syndrome is neither dominant or recessive - it is simply a genetic anomaly that occurs at conception (it's not inherited - it just happens) where part of the 15th chromosome that should be present/active is missing. This occurs either because it is totally missing (known as deletion) or because the child gets 2 chromosome 15s from the mother (instead of 1 from mom and 1 from dad which is the way it should be) and therefore that part of chromosome 15 that should be active from the father is nonexistent (this is known as uniparental disomy, or UPD)
Why is the Prader-willi syndrome recessive?
Prader-Willi Syndrome is neither dominant or recessive - it is simply a genetic anomaly that occurs at conception (it's not inherited - it just happens) where part of the 15th chromosome that should be present/active is missing. This occurs either because it is totally missing (known as a deletion) or because the child gets 2 chromosome 15s from the mother (instead of 1 from mom and 1 from dad which is the way it should be) and therefore that part of chromosome 15 that should be active from the father is nonexistent (this is known as uniparental disomy).
Is prader willi dominant or recessive?
Prader-Willi Syndrome is neither dominant or recessive - it is simply a genetic anomaly that occurs at conception (it's not inherited - it just happens) where part of the 15th chromosome that should be present/active is missing. This occurs either because it is totally missing (known as deletion) or because the child gets 2 chromosome 15s from the mother (instead of 1 from mom and 1 from dad which is the way it should be) and therefore that part of chromosome 15 that should be active from the father is nonexistent (this is known as uniparental disomy, or UPD)
What are the risk factors of angelman syndrome?
Angelman Syndrome affects one in 12,000 to one in 20,000 individuals. Exact numbers of people who have the syndrome are unknown, but can be estimated by: 1,854,057,000 (estimated world population of people less than 15 years old from the PRB 2008 Data Sheet) divided by 12,000 and by 20,000: somewhere between 92,702 and 154,504 individuals.
Russell-Silver syndrome?
DefinitionRussell-Silver syndrome is a disorder present at birth that involves poor growth, low birth weight, short height, and differences in the size of the two sides of the body.Alternative NamesSilver-Russell syndrome; Silver syndromeCauses, incidence, and risk factorsAn estimated 7 - 10% of patients with this syndrome have a defect called the maternal uniparental disomy (UPD) for chromosome 7. However, a cause cannot be identified in most patients. Most cases occur in people with no family history of the disease.The estimated number of people who develop this condition varies greatly. Some say it affects about 1 in 3,000 people. Other reports say it affects 1 in 100,000 people. Males and females are equally affected.SymptomsArms and legs of different lengthsCoffee-with-milk (cafe-au-lait) colored spotsCurving of the pinky toward the ring fingerDelayed bone ageFailure to thriveGastroesophageal reflux diseaseKidney problems, such as: Horseshoe kidneyHydronephrosisPosterior urethral valvesRenal tubular acidosisLow birth weightNormal width of headPoor growthShort armsShort height (stature)Short, stubby fingers and toesSwelling of the food pipe (esophagus)Wide forehead with a small triangle-shaped face and small, narrow chinSigns and testsThe condition is usually diagnosed by early childhood. The doctor will perform a physical exam. Signs include:Small, pointed chinThin, wide mouthTriangle-shaped face with broad foreheadThere are no specific laboratory tests to diagnose Russell-Silver syndrome. However, the following tests may be done:Blood sugarBone age testingChromosome testingGrowth hormoneSkeletal survey(to rule out other conditions that may mimic Russell-Silver syndrome)TreatmentGrowth hormonereplacement may help if this hormone is lacking. Other treatments include:Making sure the person gets enough caloriesPhysical therapySpecial educationMany specialists may be involved in treating this condition:A doctor specializing in genetics can help diagnose Russell-Silver syndrome.A gastroenterologist or nutritionist can help develop the proper diet to enhance growth.An endocrinologist may prescribe growth hormone, if it is needed.Genetic counselors and psychologists may also be involved.Expectations (prognosis)Older children and adults do not show typical features as clearly as infants or younger children. Intelligence may be normal, although the patient may have a learning disability.ComplicationsSelf esteem and emotional problems related to appearanceChewing or speaking difficulty if jaw is very smallLearning disabilitiesCalling your health care providerCall your health care provider if signs of Russell-Silver syndrome develop. The doctor may refer you to a genetic professional for a full evaluation and chromosome studies.
