[4] Cystic Fibrosis Flashcards
What is cystic fibrosis (CF)?
A genetic disorder that affects mostly the lungs, but also the pancreas, liver, kidney, and other organs
What is the inheritance of CF?
Autosomal recessive
How does CF compare to other life-limiting autosomal recessive conditions in caucasians?
It is the most common
What is the incidence of CF?
1 in 2500 live births
What is the carrier rate of CF?
1 in 25
What is the fundamental problem in CF?
A defective protein called the CF transmembrane conductance regulator (CFTR)
What is the CFTR?
c-AMP dependent chloride channel found in the membrane of cells
What effect does the defective CFTR have?
Abnormal transport of ions across epithelial cells
How does CF affect the respiratory system?
Reduced fluid in airway surfactant, leading to reduced ciliary function and retention of mucus secretions
What can retention of mucus in the lungs result in?
Chronic endobronchial infections with specific organisms e.g. Pseudomonas aeruginosa
How can CF affect the immune system?
Leads to dysregulation of inflammation and defence against infection
How does CF affect the intestine of infants?
Thick, viscous meconium is produced leading to meconium ileus
What percentage of babies born with CF are affected by meconium ileus?
10-20%
How can CF affect the pancreas?
Block it due to thickened secretions
What does pancreatic obstruction lead to?
Pancreatic enzyme deficiency and malabsorption
What percentage of children with CF are affected by pancreatic exocrine insufficiency?
90%
How does CF affect the sweat glands?
Creates sweat with excessive levels of sodium and chloride ions
On what chromosome is the CFTR gene located?
7
How many gene mutations have been show to cause distinct defects in the CFTR?
Over 900
What is the most frequent gene mutation in CF in the UK?
F508
How does the genotype affect the phenotype?
Some are associated with milder disease and pancreatic sufficiency
How has genotype began to affect treatment options?
Has allowed for CFTR potentiators such as Ivacaftor and correctors such as Lumicaftor
What are CFTR potentiators useful for?
Restoring the function of CFTR in class III and IV mutations
What are CFTR correctors useful for?
Potentially restoring CFTR numbers in class II defects