The ge­net­ics of cys­tic fi­bro­sis

Wellness Update - - Get The Facts about Cystic Fibrosis -

Cys­tic fi­bro­sis (CF) is a ge­netic dis­ease which means CF is in­her­ited. A per­son will be born with CF only if two CF genes are in­her­ited - one from the mother and one from the fa­ther. A per­son who has only one CF gene is healthy and said to be a "car­rier" of the dis­ease. A car­rier has an in­creased chance of hav­ing a child with CF. This type of in­her­i­tance is called "au­to­so­mal re­ces­sive." "Au­to­so­mal" means that the gene is on one of the first 22 pairs of chro­mo­somes which do not de­ter­mine gen­der, so that the dis­ease equally af­fects males and fe­males. "Re­ces­sive" means that two copies of the gene, one in­her­ited from each par­ent, are nec­es­sary to have the con­di­tion. Once par­ents have had a child with CF, there is a one in four, or 25 per­cent chance with each sub­se­quent preg­nancy, for an­other child to be born with CF. This means that there is a three out of four, or 75 per­cent chance, for an­other child to not have CF. The birth of a child with CF is of­ten a to­tal sur­prise to a fam­ily, since most of the time (in eight out of 10 fam­i­lies) there is no pre­vi­ous fam­ily his­tory of CF. Many au­to­so­mal re­ces­sive con­di­tions oc­cur this way. Since both par­ents are healthy, they had no prior knowl­edge that they car­ried the gene, nor that they passed the gene to the preg­nancy at the same time. Genes are founds on struc­tures in the cells of our body called chro­mo­somes. There are nor­mally 46 to­tal, or 23 pairs of chro­mo­somes in each cell of our body. The sev­enth pair of chro­mo­somes con­tains a gene called the CFTR (cys­tic fi­bro­sis trans­mem­brane reg­u­la­tor) gene. Mu­ta­tions or er­rors in this gene are what cause CF. This gene is quite large and com­plex. Over 1,000 dif­fer­ent mu­ta­tions in this gene have been found which cause CF. The risk for hav­ing a mu­ta­tion in the gene for CF de­pends on your eth­nic back­ground (for per­sons with­out a fam­ily his­tory of CF):

Newspapers in English

Newspapers from USA

© PressReader. All rights reserved.