Cystic fibrosis: a genetic disease that changes everything about your body

Health · Published 5 November 2026 Swipe more like this →

In short: Cystic fibrosis isn’t just a lung disease—it’s a whole-body condition affecting mucus, sweat, and organs. Thick mucus causes blockages, leading to diabetes, pancreatitis, and infertility. New treatments are extending lives, but diagnosis starts at birth with newborn screening.

Cystic fibrosis (CF) is an inherited genetic disorder caused by mutations in the CFTR gene, which regulates chloride and water balance in secreted fluids like mucus and sweat. The most common mutation, deletion of phenylalanine at position 508, accounts for about 70% of cases, and over 2000 mutations have been identified. These mutations disrupt the CFTR protein’s function, leading to thickened mucus and saltier sweat, which affects multiple organs.

The disease is inherited in an autosomal recessive pattern, meaning a child must inherit one mutated CFTR gene from each parent to develop CF. Parents are typically carriers, with one mutated and one normal gene. The severity of the disease varies depending on the specific mutations a patient has, with more severe mutations often causing symptoms to appear earlier in life, sometimes at birth.

CF is a multi-system disorder that primarily impacts the digestive, respiratory, and urogenital systems. In the digestive tract, thick mucus can block pancreatic ducts, preventing enzymes from reaching the intestines and leading to malabsorption, pancreatitis, and insulin-dependent diabetes. In the lungs, thick mucus creates a breeding ground for infections, leading to chronic inflammation and airway destruction. In the urogenital system, CF can cause infertility in men and reduced fertility in women.

Diagnosis typically involves newborn screening with an immunoreactive trypsinogen test and DNA testing for common CFTR mutations. A positive result is confirmed with a sweat test measuring chloride content. While CF was once a uniformly fatal disease in childhood, improved diagnosis and treatments—such as mutation-specific modulator therapies—have increased the median age of survival to 44.4 years. Today, over 50% of people with CF are 18 or older, marking a shift from a childhood-only disease to a condition that spans into adulthood.

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