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What is the genotype of two normal parents who have a child with cystic fibrosis?
Wiki User
∙ 13y ago
The genotype would have to be homozygous recessive if the child was completely effected by the disease. The "normal" paretns would have to have heterozygous recessive genotypes. This makes sense since the allele that causes sickle cell shows incomplete dominance when present with a normal allele in a pair. The "normal" parents actually would have a mixture of sickle cell shaped red blood cells combined with normal shaped ones. The carrier parents does not display symptoms of the disease since the regular red blood cells alone can fill the body's need for oxygen under normal circumstances. The only time the cArrier would notice would be under times of extreme oxygen demand, such as a sprint.
Wiki User
∙ 13y ago
Wiki User
∙ 13y agoTwo normal parents can produce a child that has cystic fibrosis if both parents are heterozygous (Cc) because cystic fibrosis is regulated by a recessive allele (c) and that is the only way a gene can have two recessive alleles that will then be active and cause cystic fibrosis. There would be a 25% of a child having cystic fibrosis with two normal, heterozygous parents.
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What are the chances of a normal person and a carrier for cystic fibrosis have a kid with cystic fibrosis?
Zero. Cystic fibrosis is an autosomal recessive disease. This means that both parents must carry a mutated gene and have a 1 in 4 (25%) chance of having a child with CF.
Why can Cystic fibrosis be inherited even if neither parent has the disease?
Cystic Fibrosis is an example of a disease inherited as an autosomal recessive genetic disorder. Both parents of a baby who has Cystic Fibrosis have one abnormal recessive gene and one normal dominant gene and are therefore, Cystic Fibrosis carriers. Carriers are said to be heterozygous because they contain one normal copy of the gene and one abnormal copy. A baby who inherits cystic fibrosis has inherited the abnormal gene from both parents and is therefore said to be homozygous recessive.
When C equals normal allele and c equals allele for cystic fibrosis Set up and complete a Punnett Square for cystic fibrosis for a couple that both have heterozygous for cystic fibrosis with no sympt?
M-> C c F C CC Cc c Cc cc phenotype- 3:1 genotype- 1:2:1
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?
If both parents are carriers on cystic fibrosis, just because two children may have the disease it doesn't mean that say,a further 3 children in future will be "normal". Inheriting genes is like a lottery. I can say though that because cystic fibrosis is recessive, every offspring born under carriers will always have a 75% chance of being phenotypically normal.
What would a genetic counselor tell parents who had cystic fibrosis or were carries of the cystic fibrosis about the chances of their children having cystic fibrosis?
If both parents are carriers then the child has a 25% chance of having cystic fibrosis. If one parent has CF and the other the other was just a carrier then the child has a 50% chance of having CF. If one parent has CF and the other has two normal genes then there is no chance of the child having CF. If one parent is a carrier and the other has two normal genes then there is no chance of the child having CF. If both parents have CF then there is a 100% chance that the child will also have CF.
What is cystic fibrosis gene disorder?
The genes on each chromosome control specific functions of the human body. The gene on chromosome 7 produces a protein called cystic fibrosis transmembrane regulator. Mutation in the DNA level of chromosome 7 leads to the absence of this protein which leads to cystic fibrosis. Cystic fibrosis is a recessive disease. It means that both copies of the gene must be defective. An affected person will have abnormal cystic fibrosis transmembrane regulator gene on each chromosome 7. Therefore both biological parents must have an abnormal gene. One abnormal copy is inherited from each parent. A person with one normal gene and one abnormal gene is called a cystic fibrosis carrier. Cystic fibrosis carriers do not show any symptoms but they may pass the abnormal gene to their children. Therefore the parents can be either cystic fibrosis carriers or affected themselves.
What are some facts about cystic fibrosis?
More than 1,000 different mutations in the CFTR gene have been identified in cystic fibrosis patients. The most common mutation (observed in 70% of cystic fibrosis patients) is a three-base deletion in the DNA sequence, causing an absence of a single amino acid in the protein product. About 2,500 babies are born with cystic fibrosis in the U.S. each year. More than 10 million Americans carry the cystic fibrosis gene but don't know it.
What is an example of allele frequency?
The frequency for the mutant cystic fibrosis allele among Caucasians is 0.025, while the frequency of the normal allele is 0.975.
What are is the percentages of a child not having cystic fibrosis with parents who both have the trait?
If both parents are just carriers of the gene that causes CF then there is a 75% chance that the child will not have CF. To break it down farther... 25% chance that they will have CF. 50% that they will be a carrier. 25% that they will have two normal genes.
Explain why the parents of someone with cystic fibrosis do not show any symptoms?
In order to have a child with cystic fibrosis, both parents must be carriers (assuming neither of the parents actually have CF; then obviously they will have symptoms). In CF, a carrier has no symptoms, unlike sickle cell anemia, where a carrier will have mild symptoms of the disease. A carrier of CF has only one defected 7th chromosome, and the other unaffected one makes the CFTR gene work correctly. When both are defected, the result is the CF disease, and normal CFTR genes are impossible to make, causing the person to have the disease.
Are Purple fingertips in cystic fibrosis patience normal?
Yes, the finger nails are often bluish in patients with Cystic Fibrosis. Clubbing of the fingernails is also seen in later stages of CF. My daughter had CF for 34 years before dying of Sepsis (blood infection), 115 days after a double lung transplant.
What are the possible phenotypes of the offspring between a parent who is a heterozygous carrier for cystic fibrosis and a homozygous normal parent?
The chances are one half. You will most likley have 2 children without the gene, and 2 with one gene. Since the normal parent has the dominate allele, the Cystic Fiborisis will not be present.
