ABCMdb

ABCC7 p.Tyr161Cys

ClinVar:	c.481T>G , p.Tyr161Asp ? , not provided c.482A>G , p.Tyr161Cys ? , not provided c.482A>C , p.Tyr161Ser ? , not provided c.481T>A , p.Tyr161Asn ? , not provided
CF databases:	c.481T>A , p.Tyr161Asn (CFTR1) ? , This putative mutation was detected by DGGE and identified by DNA fluorescent sequencing in an young patient from Southern France suffering from isolated nasal polyposis. He carries the G85E mutation on the other chromosome. c.481T>G , p.Tyr161Asp (CFTR1) ? , The mutation was detected by multiplex heteroduplex analysis on the MDE gel matrix. It was found in one Swedish patient with atypical CF (second mutationL unknown). c.482A>C , p.Tyr161Ser (CFTR1) ? , This mutation was seen in a 6 year-old CF patient whose other CF mutation is [delta]F508. The mutation and polymorphism are on the same chromosome (established in the mother). We do not yet have any clinical information. The patient was referred by S.W. Thames Regional Genetics Service. We have seen this mutation and polymorphism only once in over 100 CF chromosomes screened.
Predicted by SNAP2:	A: D (85%), C: D (80%), D: D (95%), E: D (95%), F: N (61%), G: D (91%), H: D (85%), I: D (85%), K: D (95%), L: D (85%), M: D (91%), N: D (91%), P: D (95%), Q: D (91%), R: D (95%), S: D (91%), T: D (91%), V: D (85%), W: D (85%),
Predicted by PROVEAN:	A: D, C: D, D: D, E: D, F: D, G: D, H: D, I: D, K: D, L: D, M: D, N: D, P: D, Q: D, R: D, S: D, T: D, V: D, W: D,

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[hide] The K+ channel opener 1-EBIO potentiates residual ... PLoS One. 2011;6(8):e24445. Epub 2011 Aug 31. Roth EK, Hirtz S, Duerr J, Wenning D, Eichler I, Seydewitz HH, Amaral MD, Mall MA
The K+ channel opener 1-EBIO potentiates residual function of mutant CFTR in rectal biopsies from cystic fibrosis patients.
PLoS One. 2011;6(8):e24445. Epub 2011 Aug 31., [PMID:21909392]

Abstract [show]
BACKGROUND: The identification of strategies to improve mutant CFTR function remains a key priority in the development of new treatments for cystic fibrosis (CF). Previous studies demonstrated that the K(+) channel opener 1-ethyl-2-benzimidazolone (1-EBIO) potentiates CFTR-mediated Cl(-) secretion in cultured cells and mouse colon. However, the effects of 1-EBIO on wild-type and mutant CFTR function in native human colonic tissues remain unknown. METHODS: We studied the effects of 1-EBIO on CFTR-mediated Cl(-) secretion in rectal biopsies from 47 CF patients carrying a wide spectrum of CFTR mutations and 57 age-matched controls. Rectal tissues were mounted in perfused micro-Ussing chambers and the effects of 1-EBIO were compared in control tissues, CF tissues expressing residual CFTR function and CF tissues with no detectable Cl(-) secretion. RESULTS: Studies in control tissues demonstrate that 1-EBIO activated CFTR-mediated Cl(-) secretion in the absence of cAMP-mediated stimulation and potentiated cAMP-induced Cl(-) secretion by 39.2+/-6.7% (P<0.001) via activation of basolateral Ca(2)(+)-activated and clotrimazole-sensitive KCNN4 K(+) channels. In CF specimens, 1-EBIO potentiated cAMP-induced Cl(-) secretion in tissues with residual CFTR function by 44.4+/-11.5% (P<0.001), but had no effect on tissues lacking CFTR-mediated Cl(-) conductance. CONCLUSIONS: We conclude that 1-EBIO potentiates Cl(-)secretion in native CF tissues expressing CFTR mutants with residual Cl(-) channel function by activation of basolateral KCNN4 K(+) channels that increase the driving force for luminal Cl(-) exit. This mechanism may augment effects of CFTR correctors and potentiators that increase the number and/or activity of mutant CFTR channels at the cell surface and suggests KCNN4 as a therapeutic target for CF.

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46 CFabsent CFresidual CFTR genotype Number of individuals CFTR genotype Number of individuals F508del/F508del 10 F508del/Y161C 1 F508del/W57X 1 F508del/V232D 1 F508del/G85E 3 F508del/R334W 2 F508del/120del23 1 F508del/T338I 1 F508del/182delT 1 F508del/I1234V 1 F508del/G542X 1 F508del/3272-26 A.G 1 F508del/A561E 1 F508del/3849+10 kb C.T 1 F508del/Y1092X 1 F508del/4005 +5727 A.G 1 F508del/N1303K 1 F508del/G576A 1 F508del/1525-1 G.A 2 N1303K/R334W 1 F508del/Q39X 1 F1052V/M1137R 1 F508del/Q552X 1 1898+3 A.G/ 1898+3 A.G 1 G85E/G85E 1 R334W/3199del6 1 Q552X/R1162X 1 R334W/X 1 A561E/A561E 2 dele2,3/X 1 R764X/1717-1 G.A 1 R1158X/2183AA.G 1 R1158X/R560T 1 doi:10.1371/journal.pone.0024445.t001 luminal and basolateral surfaces of the epithelium were perfused continuously with a solution of the following composition (mmol/ L): NaCl 145, KH2PO4 0.4, K2HPO4 1.6, D-glucose 5, MgCl2 1, Ca-gluconate 1.3, pH 7.4, at 37uC. Login to comment
149 (A-C) Original recordings of effects of cAMP-mediated (IBMX/forskolin) and cholinergic (CCH) activation, and effects of 1-EBIO (500 mM, basolateral) on transepithelial voltage (Vte) and resistance (Rte) in rectal tissues from a control subject (A), a CF patient with no detectable Cl2 secretion (CFabsent; R1158X/2183AA.G) (B), and a CF patient with residual Cl2 secretion (CFresidual; F508del/Y161C), as evidence by lumen-negative Vte responses (C). Login to comment

[hide] CFTR Cl- channel function in native human colon co... Gastroenterology. 2004 Oct;127(4):1085-95. Hirtz S, Gonska T, Seydewitz HH, Thomas J, Greiner P, Kuehr J, Brandis M, Eichler I, Rocha H, Lopes AI, Barreto C, Ramalho A, Amaral MD, Kunzelmann K, Mall M
CFTR Cl- channel function in native human colon correlates with the genotype and phenotype in cystic fibrosis.
Gastroenterology. 2004 Oct;127(4):1085-95., [PMID:15480987]

Abstract [show]
BACKGROUND & AIMS: Cystic fibrosis (CF) is caused by over 1000 mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene and presents with a widely variable phenotype. Genotype-phenotype studies identified CFTR mutations that were associated with pancreatic sufficiency (PS). Residual Cl- channel function was shown for selected PS mutations in heterologous cells. However, the functional consequences of most CFTR mutations in native epithelia are not well established. METHODS: To elucidate the relationships between epithelial CFTR function, CFTR genotype, and patient phenotype, we measured cyclic adenosine monophosphate (cAMP)-mediated Cl- secretion in rectal biopsy specimens from 45 CF patients who had at least 1 non-DeltaF508 mutation carrying a wide spectrum of CFTR mutations. We compared CFTR genotypes and clinical manifestations of CF patients who expressed residual CFTR-mediated Cl- secretion with patients in whom Cl- secretion was absent. RESULTS: Residual anion secretion was detected in 40% of CF patients, and was associated with later disease onset (P < 0.0001), higher frequency of PS (P < 0.0001), and less severe lung disease (P < 0.05). Clinical outcomes correlated with the magnitude of residual CFTR activity, which was in the range of approximately 12%-54% of controls. CONCLUSIONS: Specific CFTR mutations confer residual CFTR function to rectal epithelia, which is related closely to a mild disease phenotype. Quantification of rectal CFTR-mediated Cl- secretion may be a sensitive test to predict the prognosis of CF disease and identify CF patients who would benefit from therapeutic strategies that would increase residual CFTR activity.

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87 By extensive genotyping, 2 disease-causing CFTR mutations were identified in all 45 CF patients studied, including 2 novel mutations (120del23 and Y161C). Login to comment
125 According to our functional data, 3121-2AϾG, 1898ϩ1GϾT, and V520F constitute severe mutations, whereas 1898ϩ3AϾG, I148N, Y161C, V232D, T338I, I1234V, and S1159F confer residual CFTR Cl- channel function (Table 1). Login to comment