Question

The researchers consult a database of CFTR alleles identified in CF patients and find that CFTR 2756GA has been previously found in other patients. Table 1 (below) contains phenotypic information from individuals homozygous for the 2756GA, the F508del allele, and a third allele called 1831TC, a class III mutation that reduces CFTR protein function. Which alleles correspond to columns A, B, and C, respectively? Clinical features Sex, (male/female) Current age, years (meanzSD) Age at diagnosis, years (mean SD) Sweat test, mEq/l (mean+SD) FEV1% predicted (mean+SD) FVC 6 predicted (meantSD) Oxigen saturation, % (meantSD) BMI (mean+SD) Trypsine, Hg/ (mean SD) Pancreatic insufficiency, n (%) Pancreatitis, n (%) Diabetes mellitus, n (%) Lung symptoms at diagnosis (%) Bronchiectasis, n (9%) Bilateral bronchiectasis, n (%) Diffuse bronchiectasis, n (%) Bronchial colonization, n (%) Pseudomonas colonization, n (%) Hemoptysis, n (%) Sinusitis, n% Admission to hospital (mean SD) FEV1, forced expiratory volume in 1s; FVC, forced vital capacity BMI, body mass index; NS, not statistically significant c.2657+5G>A/CF (n-11) S/6 36.8+7.0 21.048.1 103.4:23.3 82.4+31.4 84.2±32.1 c.580-1G>T/CF (n-3) 0.0001 0.0001 NS 0.004 0.045 0.020 0.037 0.0001 0.0001 0.035 23.8+5.3 22.6 3.5 5.6±1.1 47.4+23.1 61.4+23.9 93.9+4.6 19.1+2.7 15.6+20.7 43 (93) 32.8 5.2 53.2:4.7 91.6 20.6 22.3+4.3 343.8 169.8 3 (27 2 (18) 3(100) 9 (20) 60 45 (100) 12 (27) 33 (73) 44 (98) 38 (84) 21 (47) 30 (66) 2 (66) 82 11 (100) 8 (77) 3 (23) 10 (91) 7 (64 11 (100) 11 (100) .3:2.7 0.0001 NS NS NS NS NS 0.001 0.024 NS 3(100) 3(100) 3(100) 2(66) 3(100)

Answer 1

Cystic fibrosis is a recessive disease caused by the mutations in the gene that produces the cystic fibrosis transmembrane conductance regulator (CFTR) protein. This protein is responsible for regulating the flow of salt and fluids in and out of the cells in different parts of the body.

A person must have a mutation in both copies of the CFTR gene to have Cystic Fibrosis.

In people with Cystic Fibrosis, mutations in the CFTR gene can disrupt the normal production or functioning of the CFTR protein found in the cells of the lungs and other parts of the body.

Mutations in the CFTR gene cause the CFTR protein to malfunction or not be made at all, leading to a buildup of thick mucus, which in turn leads to persistent lung infections, destruction of the pancreas, and complications in other organs.

The alleles found in the above figure are the alleles of cystic fibrosis