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Doctor insights on: What Is Chromosome 21

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Is Down syndrome always caused by a defect in the 21 chromosome?

Is Down syndrome always caused by a defect in the 21 chromosome?

Extra chromosome 21.: Either complete or partial trisomy for chromosome 21 is always responsible for down syndrome. ...Read more

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What is chromosome 13?

What is chromosome 13?

Chromosome 13: Chromosome 13 has genes that can be associated w breast cancer, bladder cancer, Hirschsprung’s dz, Schizophrenia, Wilson’ Dz, some forms of deafness, Retinoblastoma and other conditions. If this is not the info you were interested in then please clarify & re-ask. ...Read more

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What is an inactivated X chromosome?

Inactivated X Chromo: Great Wikipedia question. Get back with me if that dose not help. ...Read more

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How many chromosomes should you have?

46: May have pieces that are switched aroung causing different phenotypes, either good or bad. ...Read more

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Which chromosome is colorblindness from?

Which chromosome is colorblindness from?

X: The most common form of color blindness is red-green color blindness. The gene is on the x chromosome, so that is why it is most common to see males with this (and not females). ...Read more

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Why does chromosome 13 get an extra copy?

Why does chromosome 13 get an extra copy?

Error in formation: During formation of the egg, the chromosome (c) pairs that make up the normal cell separate and each egg is supposed to have 1/2 of a pair. If a 13 pair does not separate, three rather than a pair of 13's will form when the egg & sperm join. Having an extra 13 in every cell of the fetus confuses the fetal development. Miscarriage or birth defects often occur. ...Read more

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What are the important parts of chromosomes?

What are the important parts of chromosomes?

Exons mostly: The majority of the dna packed in chromosomes does not encode for specific proteins (introns), but may still have a buffer role for protecting the genetic information included in the exons (genes). ...Read more

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What are some common chromosome abnormalities?

What are some common chromosome abnormalities?

Down Syndrome: Trisomies (3 instead of 2 of a certain chromosome) are most common. Down is caused by an extra copy of chromosome 21. Patients usually have lower iq, shortened lifespans and specific facial and anatomic features. Edwards syndrome involves an extra copy of 18. The most common in utero is 16, though spontaneous miscarriage rates are very high. Patau syndrome (extra 13) also has a high mortality. ...Read more

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How many chromosome defects cause retardation?

Hundreds at least: We only know about a few hundred, probably thousands possible as each human is unique as are their choomasome array. ...Read more

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Where does the duplication of chromosomes occur?

Where does the duplication of chromosomes occur?

In the gamete: Duplication of chromosomes occurs in the gametes. The gametes are the cells responsible for creation of the egg in women or sperm in men. The process is called meiosis. Duplication of chromosomes actually occurs in two separate phases of meiosis. ...Read more

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Where on the chromosome willretinoblastoma occur?

Where on the chromosome willretinoblastoma occur?

See below: The gene for retinoblastoma is located on a region of the long (q) arm of chromosome 13 designated 13q14. ...Read more

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What happens if you are missing a sex chromosome?

What happens if you are missing a sex chromosome?

Causes a syndrome: Or infertility. Lack of an x chromosome in a female fetus usually results in a miscarriage, howevr some survive till birth and have turner syndrome. Lack of an x chromosome in males is associated with infertility. ...Read more

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What are the most common sex chromosome disorders?

What are the most common sex chromosome disorders?

Kliefelter & Turner: Most common is klinefelter's syndrome 47 XXY (male) next most common is turner syndrome 45 xo (female), following are all much less common:- triple x 47 xxx, hermaprodite 46 xx/xy mixed gonadal dysgenesis, 47 xyy & 48 xxyy syndromes. Hermaphroditism can also occur in 46 xx individuals with a fragment of a y chromosome. ...Read more

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What's worse. Missing or extra chromosome material?

What's worse. Missing or extra chromosome material?

Good question.: Missing is generally worse, with the exception of turner syndrome when one instead of two x chromosomes is present. ...Read more

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What conditions are associated with chromosome #17?

What conditions are associated with chromosome #17?

A bunch: On the medium-sized chromosome 17, there are about 1000 genes, many of which can become broken and cause disease, including neurofibromatosis type 1, charcot-marie-tooth, li-fraumini syndrome, miller-dieker lissencephaly, fronto-temporal dementia, familial mediterranean fever, and many others. The genetics home reference has more info and good links <a href="http://ghr. Nlm. Nih. Gov/chromosome/17" r. ...Read more

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What number of things are related to x-chromosome?

Hundreds: A fascinating chromosome, unlike any other. See http://ghr. Nlm. Nih. Gov/chromosome/X ...Read more

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What does it mean if a child has an extra chromosome?

What does it mean if a child has an extra chromosome?

A genetic accident: Human cells are supposed to have 23 chromosomes from father's sperm that pair up with 23 chromosomes from mother's egg. If either donation has an extra chromosome because of a genetic error, it is passed along to the fetus most common extra chromosomes in live births are on 13, 18 and 21. They cause unusual physical features, intellectual disability and, sometimes, organ malformations. ...Read more

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