Pneumoconiosis with “eggshell” calcification of the hilar lymph nodes and occupational history of sandblasting is seen with? (AIIMS May 2013)
CFTR gene is on long arm (q) of chromosome 7 (not on short arm, i.e. p)
a. Cystic Fibrosis
i. Cystic fibrosis is an inherited disease of the mucus and sweat glands.
ii. Cystic fibrosis follows on autosomal recessive transmission.
iii. There is a defect in ion transport of epithelial cells that affects fluid secretion in
• Exocrine glands (pancreas)
• Epithelial lining of respiratory, gastrointestinal and reproductive tract.
i. The primary defect in cystic fibrosis results from abnormal function of an epithelial chloride channel protein encoded by the cystic fibrosis transmembrane conductance regulator (CFTR) gene on chromosome 7q 31.2.
Normal CFTR gene product
1 Induce Cl- conductance through itself (chloride channel)
2. Inhibits Na+ conductance through ENaC
Defective (mutated) CFTR gene product in cystic fibrosis
1. Reduced or lost CI- conductance
2. Augmented sodium uptake across apical membrane