The Power Course

Cystic Fibrosis


1 ) It is autosomal dominant
2 ) Increased chloride secretion in lungs
3 ) Increased sodium and chloride content in sweat.
4 ) All of the above


Cystic fibrosis

This is an autosomal recessive disease. Mutation at long arm of chromosome 7. Gene encodes the cystic fibrosis transmembrane conductance regulator (CFTR), a regulated Cl channel located on the apical membrane of various secretory and absorptive epithelia.

These mutations are grouped into five classes.

Class I mutations do not allow for synthesis of the protein.

Class II mutations have protein processing defects.

Class III mutations have a block in their channel regulation.

Class IV mutations display altered conductance of the ion channel.

Class V mutations display reduced synthesis of the protein.

The most common mutation is class II. Loss of the phenylalanine residue at amino acid position 508.

Pseudomonas aeruginosa is common pathogen infecting the lungs

There is decreased Chloride secretion in airways with enhanced sodium absorption.

In sweet sodium reabsorption is decreased. Chloride and sodium content in sweat is increased.


Increased sodium and chloride content in sweat.

Last Modified : 29-Dec-2019

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