Cystic fibrosis transmembrane conductance regulator

The cystic fibrosis transmembrane conductance regulator (CFTR) operates as a chloride channel and regulates the other transport operations of a cell. When the CFTR gene incurs mutations, diseases such as cystic fibrosis and congenital bilateral aplasia of the vas deferens occurs. Cystic fibrosis pertains to a genetic disorder that involves the mucus glands which are situated in the respiratory and digestive systems (Antinolo et al. , 1997). Cystic fibrosis was initially described the disorder of the pancreas in terms of secretion or exocrine function.

Today, it is well known that cystic fibrosis also affects other organs such as the glands located in the intestinal lining and the biliary tree of the liver. The glands of the pulmonary bronchus are rendered to be more prone to infection when an individual has cystic fibrosis. Individuals with this disease also experience extreme bouts of sweating, even to a point that drains the entire body of essential electrolytes that are important to the maintenance of the human body. The capability to produce gametes or infertility among males and females is also affected in cystic fibrosis.

This disease is common among Caucasian populations, occurring at a prevalence rate of 1 in 3,200 Caucasian newborns (Bobadilla et al. , 2002). Cystic fibrosis is less frequent among other ethnicities, wherein it affects approximately 1 in 15,000 African Americans and only 1 in 31,000 Asian Americans. The condition of cystic fibrosis is transmitted through an autosomal recessive Mendellian pattern wherein the symptoms of the disease is expressed when two copies of the mutated gene are present in one cell (Audrezet et al. , 2004).

It should be understood that a gene is present in a cell as two copies or homologues. In addition, genes can take two conditions in terms of expression. A gene may be dominant which means that its effect is always expressed by the cell, or a gene may be recessive which means that it may not be expressed all the time and will only be expressed if two copies are present in a cell. In the case of cystic fibrosis, the disease is observed when an individual has an autosomal recessive condition for the CFTR mutation. Autosomal pertains to the cells of the body.

This homozygous or two-copy recessive condition results through the inheritance of one copy from the father and the other copy for the mother. Each of the parents who carry a mutated CFTR in combination with a normal CFTR gene are then in a heterozygous condition. They are also considered carriers because they bear one CFTR gene that is mutated and the other CFTR gene is normal. During fertilization, the mutated CFTR homologue from the germ cell of the father and the mutated CFTR homologue from the germ cell of the mother must have combined and was incorporated in the embryo.

The embryo then develops further into a fetus which later is delivery as the parents’ child. The cystic fibrosis transmembrane conductance regulator is classified as an adenosine triphosphate (ATP)-binding protein that is encoded by the CFTR gene located in chromosomal region 9q31. 2. Aside from its function in ion conductance, the CFTR gene is also responsible for influencing the functions of other proteins that are related to destruction of proteasomes or enzymes that degrade proteins in the endoplasmic reticulum.

The destruction of preoteasomes is important in controlling the quality of proteins that are produced during protein translation. The CFTR protein thus regulates the transport of ions such as sodium and chloride which are essential in the proper functioning of several organs in the body. The CFTR protein also provides a mechanism for establishing homoeostasis in the organs of the body, which involves the diffusion of ions and fluids through the cell membrane in order to keep the cells intact.

References Antinolo, G. ; Borrego, S. ; Gili, M. ; Dapena, J. ; Alfageme, I. ; Reina, F. (1997): Genotype-phenotype relationship in 12 patients carrying cystic fibrosis mutation R334W. J. Med. Genet. 34: 89-91. Audrezet, M. -P. ; Chen, J. -M. ; Raguenes, O. ; Chuzhanova, N. ; Giteau, K. ; Le Marechal, C. ; Quere, I. ; Cooper, D. N. ; Ferec, C. (2004): Genomic rearrangements in the CFTR gene: Extensive allelic heterogeneity and diverse mutational mechanisms. Hum. Mutat. 23: 343-357. Bobadilla, J. L. ; Macek, M. , Jr. ; Fine, J. P. ; Farrell, P. M. (2002): Cystic fibrosis: A worldwide analysis of CFTR mutations– correlation with incidence data and application to screening. Hum. Mutat. 19: 575-606.