Human Genetics Society of Australasia Position Statement: Population-Based Carrier Screening for Cystic Fibrosis

Since the discovery in 1989 that mutations in cystic fibrosis transmembrane conductance regulator (CFTR) underlie cystic fibrosis (CF), the most common life shortening genetic disorder in Caucasians, it has been possible to identify heterozygous mutation carriers at risk of having affected children. The Human Genetics Society of Australasia has produced a position statement with recommendations in relation to population-based screening for CF. These include: (1) that screening should be offered to all relatives of people with or carriers of CF (cascade testing) as well as to all couples planning to have children or who are pregnant; (2) the minimum CFTR mutation panel to be tested consists of 17 mutations which are those mutations that are associated with typical CF and occur with a frequency of 0.1% or higher among individuals diagnosed with CF in Australasia; (3) that genetic counselling is offered to all couples where both members are known to have one or two CFTR mutations and that such couples are given the opportunity to meet with a physician with expertise in the management of CF as well as a family/individual affected by the condition.

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A Rapid Membrane Potential Assay to Monitor CFTR Function and Inhibition

CrossRef Listing of Deleted DOIs ◽

10.1177/1087057113488420 ◽

2013 ◽

Vol 18 (9) ◽

pp. 1132-1137 ◽

Cited By ~ 14

Author(s):

Rangan Maitra ◽

Perumal Sivashanmugam ◽

Keith Warner

Keyword(s):

Cystic Fibrosis ◽

Membrane Potential ◽

Genetic Disorder ◽

Fluid Secretion ◽

Secretory Diarrhea ◽

Transmembrane Conductance Regulator ◽

Transmembrane Conductance ◽

Important Regulator ◽

Cftr Protein ◽

Cystic Fibrosis Transmembrane

The cystic fibrosis transmembrane conductance regulator (CFTR) protein is an important regulator of ion transport and fluid secretion in humans. Mutations to CFTR cause cystic fibrosis, which is a common recessive genetic disorder in Caucasians. Involvement of CFTR has been noted in other important diseases, such as secretory diarrhea and polycystic kidney disease. The assays to monitor CFTR function that have been described to date either are complicated or require specialized instrumentation and training for execution. In this report, we describe a rapid FlexStation-based membrane potential assay to monitor CFTR function. In this assay, agonist-mediated activation of CFTR results in membrane depolarization that can be monitored using a fluorescent membrane potential probe. Availability of a simple mix-and-read assay to monitor the function of this important protein might accelerate the discovery of CFTR ligands to study a variety of conditions.

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A Topological Switch in the Cystic Fibrosis Transmembrane Conductance Regulator Modulates Channel Activity and Sensitivity to Disease-Causing Mutation

10.21203/rs.3.rs-110567/v1 ◽

2020 ◽

Author(s):

Daniel Scholl ◽

Maud Sigoillot ◽

Marie Overtus ◽

Rafael Colomer ◽

Chloé Martens ◽

...

Keyword(s):

Cystic Fibrosis ◽

Single Molecule ◽

Genetic Disorder ◽

Anion Channel ◽

Atp Binding ◽

Transmembrane Conductance Regulator ◽

Channel Activity ◽

Wild Type ◽

Transmembrane Conductance ◽

Cystic Fibrosis Transmembrane

Abstract The cystic fibrosis transmembrane conductance regulator (CFTR) anion channel is essential to maintain fluid homeostasis in key organs such as the lungs or the digestive systems. Functional impairment of CFTR due to mutation in the cftr gene lead to Cystic Fibrosis (CF) the most common lethal genetic disorder. Here we observe that the first nucleotide-binding domain (NBD1) of CFTR can spontaneously adopt an alternative conformation that departs from the canonical NBD fold previously observed for CFTR and other ATP-binding cassette (ABC) transporter proteins. Crystallography studies reveal that this conformation involves a topological reorganization of the β-subdomain of NBD1. This alternative state is adopted by wild-type CFTR in cells, where it leads to enhanced channel activity. Single-molecule fluorescence resonance energy transfer microscopy shows that the equilibrium between the conformations is regulated by ATP binding. However, under destabilizing conditions, such as a the prominent disease-causing mutation F508el , this conformational flexibility enables unfolding of the β-subdomain. Our data indicate that in wild-type CFTR switching to this topologically-swapped conformation of NBD1 regulates channel function, but, in the presence of the F508del mutation, it allows domain misfolding and subsequent protein degradation. Our work provides a framework to design conformation-specific therapeutics to prevent noxious transitions.

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A Topological Switch Enables Misfolding of the Cystic Fibrosis Transmembrane Conductance Regulator

10.1101/2020.07.09.195099 ◽

2020 ◽

Author(s):

Daniel Scholl ◽

Maud Sigoillot ◽

Marie Overtus ◽

Rafael Colomer Martinez ◽

Chloé Martens ◽

...

Keyword(s):

Cystic Fibrosis ◽

Single Molecule ◽

Genetic Disorder ◽

Resonance Energy ◽

Anion Channel ◽

Atp Binding ◽

Transmembrane Conductance Regulator ◽

Wild Type ◽

Transmembrane Conductance ◽

Cystic Fibrosis Transmembrane

AbstractCystic Fibrosis (CF) is a common lethal genetic disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel. Misfolding and degradation of CFTR are the hallmarks of the predominant mutation, F508del, located in the first nucleotide binding domain (NBD1). While the mutation is known to affect the thermal stability of NBD1 and assembly of CFTR domains, the molecular events that lead to misfolding of F508del-CFTR remain elusive. Here, we demonstrate that NBD1 of CFTR can adopt an alternative conformation that departs from the canonical NBD fold previously observed for CFTR and other ATP-binding cassette (ABC) transporter proteins. Crystallography studies reveal that this conformation involves a topological reorganization of the β-subdomain of NBD1. This alternative state is adopted by wild-type CFTR in cells and enhances channel activity. Single-molecule fluorescence resonance energy transfer microscopy shows that the equilibrium between the conformations is regulated by ATP binding. Under destabilizing conditions, however, this conformational flexibility enables unfolding of the β-subdomain. Our data indicate that in wild-type CFTR switching to this topologically-swapped conformation of NBD1 regulates channel function, but, in the presence of the F508del mutation, it allows domain misfolding and subsequent protein degradation. Our work provides a framework to design conformation-specific therapeutics to prevent noxious transitions.

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