HTHSCI 1DT3 Lecture Notes - Lecture 18: Cystic Fibrosis, Missense Mutation, Nonsense Mutation
13 Aug 2020
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Mod. 2-2 & 1-13, 14 cystic fibrosis (cf) 3. Ting joe li yah: deletion mutation of three nucleotides that comprise the codon for phenylalanine (ctt) at position 508. Cftr protein will be produced that lack the phenylalanine residue (this will cause remodelling and refolding of protein) Mutation specific treatments: cftr potentiator vx-770 (kalydeco) to target class iii mutation (5% of all cf patients) phase iii, there are normal levels of surface cftr. Hence, easier to correct: however, gating defect cause lower cl- transport, potentiators will increase cftr gating and increase chloride flux, patients undergoing treatment have dose-dependent reduction in sweat chloride. Secretion of sodium and chloride into sweat glands (lumen) are cftr independent. However, before exiting the sweat gland, chloride will be absorbed by cftr. Hence, potentiator targets this: and increased fev1 % predicted. However, only work in patients with g551d mutation (5% of cf patients: this drug is very expensive to give to patients.
