What does it mean to be heterozygous for cystic fibrosis?

What does it mean to be heterozygous for cystic fibrosis?

Someone who is heterozygous (Ff) or homozygous (FF) for the dominant allele will not develop cystic fibrosis. In example one, both parents are heterozygous Ff – they are carriers of the disease. This means they have the cystic fibrosis allele and might pass it on to their children.

What is the heterozygote advantage with cystic fibrosis?

Recently a heterozygote advantage was suggested to explain the high incidence (1:25 carrier individuals in Europeans) of the cystic fibrosis gene. This selective advantage was speculated to be due to a high resistance to chloride-secreting diarrhea, including cholera.

Is cystic fibrosis compound heterozygous?

As this mutation is consistent with the observed clinical manifestations of CF and no other mutations were detected after scanning the gene sequence, we suggest that their CF phenotypes are caused by the compound heterozygous mutation, c. 400 A > G p.

What does heterozygous carrier mean?

If the alleles are heterozygous, the dominant allele would express itself over the recessive allele, resulting in brown eyes. At the same time, the person would be considered a “carrier” of the recessive allele, meaning that the blue eye allele could be passed to offspring even if that person has brown eyes.

What causes heterozygote advantage?

A heterozygote advantage describes the case in which the heterozygous genotype has a higher relative fitness than either the homozygous dominant or homozygous recessive genotype. The specific case of heterozygote advantage due to a single locus is known as overdominance.

What is a real life example of heterozygous?

The classic example of heterozygous advantage is sickle cell anemia where humans who are homozygotic for sickle shaped cells (pictured opposite) suffer from a near lethal condition.

Can CF carriers have babies?

When two CF carriers have a baby, there is a 25 percent chance that their baby will be born with the disease and a 50 percent chance that their baby will be a carrier of a CF gene mutation, but not have the disease themselves.

Do CF carriers have salty sweat?

In sweat glands chloride channels have an additional function; they recycle salt out of the glands and back into the skin before it can be lost to the outside world. Excessively salty sweat, in fact, is the definitive diagnostic test for cystic fibrosis, which strikes about 1 of every 2,500 white babies.

What causes heterozygous?

In medical genetics, compound heterozygosity is the condition of having two or more heterogeneous recessive alleles at a particular locus that can cause genetic disease in a heterozygous state; that is, an organism is a compound heterozygote when it has two recessive alleles for the same gene, but with those two …

What are the clinical issues associated with being heterozygous?

in heterozygotes has been reported together with signs of a slightly increased cerebral irritability, a possible slight increase of risk for mental disease, and an increase of blood phenylalanine levels in stress situations.

What is the relationship between heterozygous cystic fibrosis and chest disease?

The degree of chest disease likely in the heterozygotes in whom the lung is involved would generally not approach that found in adults with CF.

What is a manifesting heterozygote?

The interesting case described on page 278 of this issue of Thorax raises a number of points. 5 The authors claim that their patient, born to consanguineous parents and with a history of having lost two infant siblings with CF, is a manifesting heterozygote—that is, is someone with only one CF mutation but showing the phenotype of the disease.

Can genetic analysis solve the problem of cystic fibrosis?

Since the discovery of the CFTR gene in 1989 and the ongoing discovery of mutations associated with CF (the mutation count now stands at over 800), genetic analysis has brought a new sophistication to the area but has not solved all the problems.