cystic fibrosis Flashcards
what is CF
an inherited autosmal receive disease, the result of a gene mutation- single gene defect on chromosomes 7- responsible for encoding the CF membrane conductive regulator, a transmembrane protein involved in ion transport called cystic fibrosis transmembrane regulating protein (CFTR). this defect leads to a compromise ion transport- it impairs transport of chloride ions, and also addicts levels of sodium and water in cells
what does CF affect
affects several organs causing ducts to become obstructed with mucus-inflammation and replacement of damaged cells within CT (scarring)
what does the CFTR protein do
this is a channel protein, it controls the flow of water and chloride ions between membranes. when the structure is changed, passage molecules and ions is blocked. the most common pathology of CF. there are over 1500 mutations of the CFTR gene that produce different variations of CFTR protein- treatment=difficult
defect in CFTR results in- respiratory disease
abnormally concentrated fluid in the lungs, leads to vicious secretion in the airways, due to dehydrated airway mucous is not cleared, which predisposes patients to disease and infection- scarring lungs
defect in CFTR results in- high sodium sweat
chloride ions not absorbed leading to prevention of sodium absorption- low blood salt level- limit recognition of thirst= dehydration
defect in CFTR results in- pancreas insufficiency
production of enzymes is normal but abnormal ion transport leads to stagnation in pancreatic duct- causes diabetes later in life
defect in CFTR results in- billiary disease
abnormal ion transport reduces water movement in the lumen resulting in concentrated bile which can damage walls of lumen- damage to bowel
defect in CFTR results in- infertility
male CF patients are often infertile due to absence of vas deferences prevent transport of sperm from testes to the urethra
defect in CFTR results in- cirrhosis of the liver
due to abnormality in ion transport
defect in CFTR results in- gastrointestinal disease
intraluminal water deficiency causes problems with bowel movement
defect in CFTR results in- what can they all be related to
all of these can be related to a lack of Na+, CL- or water diffusion problems
prevalence
1 in 25 caucasians carries the gene, 2 carries have a 1 in 4 chance of having an affected baby and 1 in 2 chance that their baby will be carrier. affects more than 10.4k people in UK, 1 in 2.5 babies are born with CF, claims 2-3 lives per week, identified in early life now- higher survival rate
diagnosis- genetic testing
if someone has a history of CF in their family, a partner with CF, or a child with the condition, they may have carrier testing. a simple mouthwash of blood test can be determine if someone is a carrier of the faulty gene that causes CF.
diagnosis- heel prick test
since 2003 in Scotland and 2007 in ukm all babies born have been screened for CF using heel prick test. as a result most children are diagnosed with CF shortly after birth
diagnosis- sweat test
done for babies suspected to have CF, it is performed as part of a follow up process to screening. in people with CF there is a problem in the transport of chloride across the cell membranes, which results in higher concentrations of chloride in the sweat. the test measures this concentration and is done by collecting a small amount of sweat from the arm/leg
