Chloride receptor defect is responsible for:

Ans: A (Cystic fibrosis) Ref: Harrison's 18th edn, pg 2149Explanation:Cystic FibrosisAutosomal recessiveMutation in CFTR (cysic fibrosis transmembrane conductance regulator) geneClinical FeaturesBronchiectasisExocrine pancreatic insufficiencyIntestinal dysfunctionAbnormal sweat gland functionUrogenital dysfunctionCF airway epithelia exhibit abnormal Cl- secretion and Na+ absorptionPredisposes to infections. Staph, aureus. Pseud.aeruginosa. Others are H.influenza. Alcaligenes. Burkholderia, Proteus. E.coli, Klebsiella, AspergillusLack of CFTR Cl- channel in the apical membrane of pancreas, failure to secrete NaHCO3 and water, destruction of the pancreasIn the sweat glands, inability to absorb Cl- from the sweat leads to high Cl- concentrations in sweat measured after iontophoresis of cholinergic agentsSpirometry: | RV/TLC, | FVC and | FEV1CXR- hyperinflation, brochiectasis, right upper lobe (Earliest involved)Clubbing, pneumothorax, hemoptysis, corpulmo- naleGIT: Meconium ileus, DIOS, protein and fat malabsorption, diabetes laterGUT: Late onset puberty, azoospermia, female infertility- TreatmentGene therapy of CFTR geneClearance of secretions with hypertonic saline, antibioticsRecombinant human DNAse to degrade DNA in sputumPancreatic enzyme replacement, Vit E and K. InsulinMegalodiatrizoate enema for acute intestinal obstructionUrodeoxv cholic acid for cholestatic liver diseasePredisposed to renal stones and osteoporosis