Lecture 9

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Questions and Answers

What is the most appropriate method to confirm the diagnosis of cystic fibrosis in Joe?

Conduct a blood test to analyze the DNA for cystic fibrosis gene mutations

Perform a sweat test to measure the chloride levels in the sweat (correct)

Administer a chest X-ray to assess lung condition

Undertake a sputum culture to identify specific bacteria causing infection

What is the significance of Joe's Na+ level of 87mmol/L in the sweat test?

It suggests a different respiratory condition unrelated to cystic fibrosis

It indicates a potential risk for meconium ileus

It is within the normal range and rules out cystic fibrosis

It indicates elevated chloride levels, suggesting cystic fibrosis (correct)

What role does the CFM1 gene on Chromosome 19 play in cystic fibrosis?

It may determine the risk of developing meconium ileus (correct)

It regulates lung function in cystic fibrosis patients

It directly causes cystic fibrosis symptoms

It is responsible for the production of mucus in the respiratory system

What is the primary concern regarding cystic fibrosis pulmonary infection?

Progressive destruction of lung tissue leading to respiratory failure Signup and view all the answers

What is the most common mutation found in 80-85% of hemochromatosis cases?

c.845G>A, resulting in Cysteine to Tyrosine (p.C282Y) Signup and view all the answers

Which mutation does not result in clinically manifest haemochromatosis when homozygous?

c.187C>G, resulting in Histidine to Aspartic acid 63 (p.H63D) Signup and view all the answers

Why is population screening not recommended for hemochromatosis?

Low penetrance and no actionable knowledge Signup and view all the answers

What are the two main methods for diagnosing CF mutations?

Targeted mutation panel and PCR amplification with Single Strand Conformation Polymorphism Signup and view all the answers

How many classes are CF mutations categorized into based on their impact on protein production and function?

Five classes Signup and view all the answers

What do CFTR modulator therapies aim to correct?

Malfunctioning protein made by mutated CFTR Signup and view all the answers

What is the purpose of the new triple therapy Kaftrio, approved in 2020?

Increase the quantity and function of the F508del-CFTR protein at the cell surface Signup and view all the answers

What are the implications for Joe's extended family in relation to CF?

Availability of carrier testing and cascade screening Signup and view all the answers

What are the purposes of genetic screening for CF?

Carrier screening, testing of embryos, prenatal testing, and newborn screening Signup and view all the answers

How is newborn screening for CF established?

Through the Guthrie test Signup and view all the answers

Why is CF population carrier screening not implemented?

Due to ethical concerns and the need for complementary approaches Signup and view all the answers

What is used to design custom CFTR mutation panels for different geographic regions?

Next-generation sequencing (NGS) Signup and view all the answers

What does screening for carriage of CF mutations depend on?

Ethnic background Signup and view all the answers

What clinical condition is characterized by iron accumulation and associated with variant alleles of the HFE gene 6p21?

Haemochromatosis Signup and view all the answers

Study Notes

Cystic Fibrosis and Genetic Testing

Cystic Fibrosis (CF) mutations can be diagnosed using a targeted mutation panel or by scanning exons with PCR amplification and Single Strand Conformation Polymorphism.
CF mutations are categorized into five classes based on their impact on protein production and function.
CFTR modulator therapies aim to correct the malfunctioning protein made by mutated CFTR, using read-through compounds, correctors, and potentiators.
New triple therapy Kaftrio, approved in 2020, is designed to increase the quantity and function of the F508del-CFTR protein at the cell surface.
Implications for Joe's extended family include the availability of carrier testing and cascade screening.
Genetic screening for CF serves purposes such as carrier screening, testing of embryos, prenatal testing, and newborn screening for early detection and intervention.
Newborn screening for CF is established through the Guthrie test, with a 1 in 1,500 prevalence.
CF population carrier screening is not implemented due to ethical concerns and the need for complementary approaches.
Screening adults for carriage involves testing for common mutations and using next-generation sequencing (NGS) for affordable genetic testing with a high detection rate.
NGS is used to design custom CFTR mutation panels for different geographic regions, with around a 95% detection rate.
Screening for carriage depends on ethnic background, with different mutation prevalences in various populations.
Haemochromatosis is a clinical condition characterized by iron accumulation and is associated with variant alleles of the HFE gene 6p21, with phlebotomy as a treatment option.

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Description

Test your knowledge of cystic fibrosis and genetic testing with this quiz. Explore topics such as CF mutation diagnosis, classification of mutations, CFTR modulator therapies, implications for family members, genetic screening purposes, and screening methods. Learn about the latest advancements, such as the Kaftrio triple therapy, newborn screening, and next-generation sequencing technology.