WHAT CHROMOSOME IS AFFECTED BY CYSTIC FIBROSIS
WHAT CHROMOSOME IS AFFECTED BY CYSTIC FIBROSIS Cystic fibrosis (CF) is a hereditary genetic disorder that primarily affects the lungs and digestive system, leading to severe respiratory and nutritional issues. Understanding its genetic basis is crucial for diagnosis, management, and genetic counseling. The key to this understanding lies in identifying the specific chromosome involved in the disorder.
Cystic fibrosis is caused by mutations in a specific gene called the CFTR gene, which stands for Cystic Fibrosis Transmembrane Conductance Regulator. This gene provides instructions for making a protein that functions as a channel for chloride ions across cell membranes. Proper chloride transport is essential for maintaining the balance of salt and water on many surfaces within the body, such as the lungs and pancreas. When this process is disrupted due to mutations in the CFTR gene, thick and sticky mucus forms, clogging airways and obstructing ducts, leading to the characteristic symptoms of CF.
The CFTR gene is located on the long arm (also known as the ‘q’ arm) of chromosome 7. Chromosomes, which are structures within cells that carry genetic information, are numbered from 1 to 22, plus the sex chromosomes X and Y. In the case of cystic fibrosis, it is specifically chromosome 7 that harbors the gene mutation responsible for the disease. The CFTR gene spans a considerable length on this chromosome, and over 2,000 different mutations have been identified that can cause CF, with the ΔF508 mutation being the most common worldwide.
Inheritance of cystic fibrosis follows an autosomal recessive pattern. This means that a person must inherit two copies of the mutated CFTR gene—one from each parent—to develop the disease. If an individual inherits only one mutated copy and one normal copy, they are consid
ered a carrier and usually do not show symptoms but can pass the gene to their children. When two carriers have a child together, there is a 25% chance for the child to inherit cystic fibrosis, a 50% chance to be a carrier, and a 25% chance to inherit two normal copies.
Genetic testing for mutations in the CFTR gene is a common diagnostic tool. It can identify carriers and confirm a diagnosis in symptomatic individuals. Understanding that the gene is located on chromosome 7 helps researchers and clinicians focus their studies and develop targeted therapies. Advances in gene editing and personalized medicine continue to hold promise for treating or even curing cystic fibrosis in the future.
In summary, the affected chromosome in cystic fibrosis is chromosome 7, which contains the CFTR gene. Mutations in this gene interfere with chloride ion transport, leading to the clinical manifestations of the disease. Recognizing this genetic basis is vital for early diagnosis, management, and genetic counseling, ultimately improving quality of life for individuals with cystic fibrosis.
