by mcbill

Question posed by sacre bleu!: 2 short SHORT genetics questions…not that hard i just cant figure it out?
A woman who is heterozygous for the alleles of the gene that confers cystic fibrosis is married to a man who is also heterozygous for this gene. What percentage of their children are expected to develop cystic fibrosis?

According to the punnett square, i think 75%? Am I right?

Also, another short one…

If a woman with one copy of the Huntington’s allele marries a man who is homozygous recessive, what percentage of their children are expected to develop Huntington’s disease?

No idea how to do this one. Thanks.

The best answer:

Answer by Dustfinger .
1) If cystic fibrosis is dominant, 75% of the children will have it, yes.

2) I have no idea…

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Technorati Tags: cant, figure, GENETICS, hard, just, questions...not, short

by cstmweb

Question posed by Wilf J: Simple Mendelian genetics monohybrid question?
Kathy’s brother has cystic fibrosis. Her husband has no family history of CF. What is the chance that Kathy’s child is a carrier of the CF mutation?

The answer is 2/3 x 1/2 to yield a probability of 1/3, but I cannot figure out how the 2/3 and 1/2 fractions are derived.

Much thanks in advanced!
Cystic fibrosis in this question is AUTOSOMAL RECESSIVE by the way.

The best answer:

Answer by skyblue5600
So looking at the pedigree, you can assume the parents didn’t have CF (its not mentioned) but you can deduce that they both must be carriers, since they had a son with CF. Now since they have genotypes Aa X Aa, 1/4 of their kids will have CF (aa), 1/2 of their kids will be carriers, but outwardly normal (Aa) and 1/4 of their kids will be non-carriers and completely normal (AA). Now, we know Kathy doesn’t have CF, so she’s either AA or Aa. This means there’s a 2/3 chance that she’s Aa and a 1/3 chance she’s AA. Now since her husband has no family history, it can be assumed he is not a carrier, so he’s AA. Now, if Kathy was a carrier Aa, then when they have kids (AA X Aa), 1/2 of them will be carriers, 1/2 won’t. So altogether, the likelihood is 2/3 X 1/2

If you know better then please let us know below.

Technorati Tags: GENETICS, Mendelian, monohybrid, question, Simple

by mcbill

Question posed by jacket2230: Cystic Fibrosis questions?
After a scare with my nephew, my pediatrician and I discussed doing DNA testing through Ambry genetics. We did go through with it and my 5 year olds test have came back and he has G576A on exon 12 and R668C on exon 13. What does this mean? Does he have CF? Is there a such thing as mild CF? or could he just be a carrier? Thanks in advance.
not that the discussion with the dr has ended there. I have a wonderful relationship with my pediatrician, but as we all know they do not specialize in everything so I am waiting on an appointment with a pulmonary Dr. Also, if you have ever played the waiting game with your children and a possible illness you would search any and all avenues. So that is why I’m reaching out to other people who have possibly gone through the same thing. i would appreciate a little more compassion, but you must be one of those nurses who just need to get out while you can…..
Also still waiting on results for my 3 year old son
Thanks for your input hels. Your the kind of people I need to talk to who actually know about real life.
Thank you Barry M. I do have an email sent to Steve Keils the Director over Ambry genetics and I am waiting on his response. He does have his number listed so I’m tempted to pick up the phone today and just give him a call. Thanks

The top answer:

Answer by heogog
You really need to call the doc back and ask those questions to him. If you weren’t given that information at your appointment, then the doctor owes you a detailed breakdown on what all that means.
YA isn’t the place to be asking those kinds of really important specific questions.

Agree or disagree? Leave your own thoughts below.

Technorati Tags: cystic, fibrosis, questions

by Tanya Dawn

A question from cc: Cystic Fibrosis?
What type of DNA changes might cause cystic fibrosis? How are these changes reflected in the symptoms of this disorder?

Chosen answer:

Answer by Josh
Cystic Fibrosis, hereditary disorder in which the exocrine glands secrete abnormally thick mucus, leading to obstruction of the pancreas and chronic infections of the lungs, which generally causes death in childhood or early adulthood. Some mildly affected patients may survive longer. No cure for the disease has yet been found. Patients with pancreatic insufficiency can take pancreatic enzymes with meals. Those with respiratory infections are treated with antibiotics, with aerosols that relieve constriction of the airways and liquify the thick mucus, and by physiotherapy to help patients cough up the obstructing secretions. Intestinal obstruction, which occurs primarily in infancy (meconium ileus), may require surgery.

If both parents carry the gene responsible for the disease, they have a one-in-four chance of having an affected child. In 1989, the gene responsible for cystic fibrosis was identified on chromosome 7. Since that time more than 300 different mutations in the cystic fibrosis gene have been described, and tests have been developed to detect the most common alterations. These tests can identify unaffected carriers of the disorder. Trials are currently under way to use the recombinant human enzyme DNAase to liquify the thick mucus. The use of gene therapy to treat cystic fibrosis is also in the experimental stage.

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Technorati Tags: cystic, fibrosis

Question posed by Drama Queen: If only one parent is a carrier of Cystic Fibrosis can the child still be a carrier?
I know its a 1/2 chance that your kid is gonna be a carrier of cystic fibrosis if both parents have it but what if only one parent had it would it be 1/4 or is it impossible
Also if u no any links about cystic fibrosis

No 1 answer:

Answer by To.The_End
1/4.

How about adding your own answer to the comments below!

Technorati Tags: Carrier, child, cystic, fibrosis, only, parent, still

Question by Zhang223: From past history, we know there is a 2/3 chance that Jane is a carrier of cystic fibrosis. Her husband is a?
From past history, we know there is a 2/3 chance that Jane is a carrier of cystic fibrosis. Her husband is a carrier. If she is a carrier, there is a ¼ chance that a son will have the disease. If not, a son cannot get the disease. Transmission is independent from child to child. If they have 3 sons, all of whom do not have the disease, what is the probability that she is a carrier?

Most detailed answer:

Answer by Etienne de Quercy, Big Pointure!
use the Pearson’s chi square test

How about adding your own answer to the comments below!

Technorati Tags: Carrier, chance, cystic, fibrosis, from, history, husband, Jane, know, past, there

by Tanya Dawn

A question asked by Mummy of 1 expecting #2: Can smoking during pregnancy cause cystic fibrosis?
My 15 month old nephew has had serious trouble breathing since the day he was born, been in and out of hospital. My sister in law has just been told by doctors they’re pretty sure it may be cystic fibrosis. It wont be for a month or so before before they can clarify it, but I am doing some research just in case as I don’t really know anything about the disease. My sister in law smoked cigarettes all though her pregnancy ( yes it is completely wrong! ) and I was just wondering if this can be a cause? If not, what can cause it?

Selected answer:

Answer by Mary
no- CF is a genetic disorder in which both parents are carriers of the gene.

If you know better then please let us know below.

Technorati Tags: cause, cystic, during, fibrosis, pregnancy, smoking

by fakelvis

Question by Clean: What was mentioned as an inexpensive treatment for cystic fibrosis?

Top answer:

Answer by Never_Cease_To_Be_Amazed
Aspirin, but I would be skeptical.

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Technorati Tags: cystic, fibrosis, inexpensive, mentioned, treatment

by k-ideas

Question posed by angeleyez2936: Can someone explain this genetics question to me?
A couple who are both carriers of the gene for cystic fibrosis have two children who have cystic fibrosis. What is the probability that their next child will be phenotypically normal?

The correct answer is 75% but I don’t see how?

Selected answer:

Answer by beanthedoctor
The point is that the probability doesn’t depend on previous children. So, if both parents are normal and carry a copy of cystic fibrosis gene, then every time they have a kid they have 50% x 50% (25%) chance of it getting both copies of the cystic fibrosis gene. Therefore, 100-25 = 75% chance they will have a normal child every time..

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A question asked by Mallory: What should I do if my 4 year old has symptoms of cystic fibrosis?
My 4 year old son has had breathing problems and been hospitalized twice for croup, pneumonia once and constantly has a deep cough. His father is a carrier for cystic fibrosis and im not. Should he be tested? His half brother has been diagnosed with CF.

Most comprehensive answer:

Answer by manda
ask a doctors opinion

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Technorati Tags: cystic, fibrosis, should, symptoms, year