Flashcards in Integration of Pathology and Genetics - Cystic Fibrosis Deck (21)
What is the inheritance pattern of cystic fibrosis?
What is the most common population of cystic fibrosis carriers in the US?
North American Caucasians
What are the clinical features of CF?
- Pulmonary symptoms
What is the function of cystic fibrosis transmembrane regulator (CFTR)?
Has many functions - main function is as a Cl- channel but it is also a regulatory protein for other channels - its functions are TISSUE specific
What is the most common mutation in CF?
F508 3 base deletion which removes a phenylalanine
What are the most serious types of CF mutations?
Class I - decrease in severity as the class number increases
What is the generally accepted theory for the pulmonary pathogenesis of CF?
ASL (airway surface liquid) has low volume due to lack of regulation of ENaC, Na is hyper- absorbed, Cl follows through other pathways, water follows passively, low volume of ASL leads to increased mucus concentrations, delayed transport, mucus adhesions, decreased ciliary beat and inhibited bacterial clearance.
What can be seen on x-ray of CF?
• Upper lobe predominant bronchiectasis
– Signet ring
– Tram tracking
• Peribronchial cuffing
• Nodules/mucous impaction
Why are CF patients more susceptible to Pseudomonas?
Generally unknown but thought to be due to the ASL milieu and the cell receptors
What are the effects of CF on the sinuses?
• Hypertrophy/hyperplasia of secretory elements
• Inflammation and edema
What are the effects of CF on the pancreas?
Obstruction of ducts with inspissated secretions leads to dilation, destruction and fibrosis - fat malabsorption
How can fat absorption in CF patients be evaluated very easily?
Look at Vitamin D/E/K/A levels
What is CF related diabetes?
• Pancreatic endocrine insufficiency
• Symptoms- polyuria, polydipsia, weight loss, unexplained drop in lung function
How does CF lead to bone and joint disease?
Large majority due to Vitamin D deficiency and calcium malabsorption
What is the effect of CF on the GU of females?
Endocervicitis, mucus distended cervical glands – Anovulatory with 1/5 infertile
What is the effect of CF on the GU of males?
Failure in transport (vas deferens) with 98% infertile
What is the effect of CF in the sweat glands?
Sweat becomes salty with increased sensitivity to dehydration
What are some lab tests that can diagnose CF?
– Sweat test
– Genetic test
– Nasal potential
How might hypertonic saline work in CF treatment?
Increased osmolality of ASL will draw more water out
What is a potentiator?
Protein that binds to the dysfunctional CFTR protein and corrects its folding to regain function