Genetic disorders cystic fibrosis

In many genetic disorders, cystic fibrosis included, the analysis begins before the responsible gene and its protein... 

Among its many other applications, DNA fingerprinting is widely used for the diagnosis of genetic disorders. Cystic fibrosis, hemophilia, Huntington s disease, Tay-Sachs disease, and sickle-cell anemia are among the many diseases that can be detected, enabling early treatment of an affected child. In addition, the U.S. Department of Defense now requires blood and saliva samples from all military personnel. The samples are stored, and DNA is extracted should the need for identification of a casualty arise. 

Cystic fibrosis (CF) is a recessive genetic disorder prevalent among whites in North America and certain parts of northern Europe. It is characterized by chronic bacterial infections of the airways and sinuses, fat maldigestion due to pancreatic exocrine insufficiency, infertility in males due to abnormal development of the vas deferens, and elevated levels of chloride in sweat (> 60 mmol/L). 

Recombinant DNase preparations have been used in the treatment of cystic fibrosis since the end of 1993. This genetic disorder is common, particularly in ethnic groups of northern European extraction, where the frequency of occurrence can be as high as 1 in 2500 live births. A higher than average incidence has also been recorded in southern Europe, as well as in some Jewish and African-American populations. 

A family medical history can identify people with a higher-than-usual chance of having common disorders, such as heart disease, high blood pressure, stroke, certain cancers, and diabetes. These complex disorders are influenced by a combination of genetic factors, environmental conditions, and lifestyle choices. A family history also can provide information about the risk of rarer conditions caused by mutations in a single gene, such as cystic fibrosis and sickle cell anemia. 

Although ER protein degradation seems not be essential for yeast cells, the breakdown of mutated and thus malfolded ER proteins is often associated with severe diseases in human (Ciechanover, 1998 Plemper and Wolf, 1999). The importance of this process in the understanding of genetic disorders like cystic fibrosis and a 1-antitrypsin deficiency has been outlined above. In the following we will give further examples on how viruses or toxins may misuse the machinery for the ER protein degradation to interfere with cellular processes. 

As discussed above, in the case of phenylketonuria, early intervention can make the difference between mental retardation and a near normal life course for a newborn. Congenital adrenal hyperplasia and maple syrup urine disease are two examples of neonatal hereditary disorders where early diagnosis and medical intervention can make the difference between life and death for the newborn. In addition, in a number of genetic diseases, early diagnosis and treatment can help ameliorate symptoms these include fragile X syndrome, homocystinuria, sickle cell anemia, cystic fibrosis, and many /1-thalassemias. 

Bayesian probabilities are absolutely reliant upon an accurate family history of the disease in question. Family history affects the prior or a priori likelihood that a propositus is a carrier for a genetic disease. Because many hereditary disorders are autosomal recessives and manifest rarely in a sibship, any record of a known hereditary disorder can be important in providing an accurate risk reduction. This can be particularly important in cystic fibrosis, where one of the mutations is often known in affected individuals while the other is often private and uncharacterized. Fven an affected first cousin can boost the a priori probability in a Caucasian non-Jew from 1/241 to 1/8. 

T Defects in protein folding may be the molecular basis for a wide range of human genetic disorders. For example, cystic fibrosis is caused by defects in a membrane-bound protein called cystic /ibrosis transmembrane conductance regulator (CFTR), which acts as a channel for chloride ions. The most common cystic... 

There are many potential uses for recombinant DNA technology. Agricultural products, as is discussed in Chapter 15, can be made bug-resistant and spoil-resistant. The technology may also be used to treat genetic disorders, such as sickle-cell anemia, muscular dystrophy, cystic fibrosis, and lupus, and may even address the question of why our bodies deteriorate with age. 

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