Cystic Fibrosis - AP biology class material

Cystic fibrosis(=CF or mucoviscidosis)

This disease affects human. The symptoms of Cystic fibrosis mainly appear critically in the lungs, including the intestine, pancreas, and liver. The main cause of these harms on lungs and other organs is due to abnormal transport of sodium and chloride across epithelium, thus strengthening the viscosity of secretions. Usually the chloride transport channels are defective or even absent in the plasma membranes. As a result of the absence, extracellular chloride is thick. By the default in lungs’ functioning there comes difficulty in breathing and this is the most serious symptom that might lead to lung infections. These lung infections are hardly treated with, and it’s not cured by any antibiotics and other medications. Other symptoms are poor growth, infertility, diarrhea, and sinus infectionsaffect other parts of the body.

The mutated gene that causes CF occurs inside the protein called, cystic fibrosis transmembrane conductance regulator (CFTR). The symptoms in the main organs are due to malfunction of this gene in the CFTR, since this gene plays a crucial role regulating the components of digestive juices, sweat, and mucus. To block the expression of this disease, only one is needed to prevent cystic fibrosis, although most healthy people without CF have a pair of CFTR gene. In conclusion, CF is an autosomal recessive inheritance that develops when neither gene works properly.

CF occurs commonly among Caucasians; in the rate of one over 25 carries one allele that cause CF in European race. Ireland has high probability of CF in the unit of world; 2.98 per 10.000. It is a serious disease in Ireland and social problem since Ireland has the hugest proportion of families that have more than one child infected of CF.

.  For cystic fibrosis to occur by the point mutation there’s the deletion of gene. By the deletion of 3 base-pair deletion, there’s no frame shift. But one amino acid is missing- leading to the cystic fibrosis.

References: http://www.ornl.gov/sci/techresources/Human_Genome/posters/chromosome/cftr.shtml(Picture)

           http://en.wikipedia.org/wiki/Cystic_fibrosis

           The Biology (the book we use)