Cystic Fibrosis

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Description

Cystic fibrosis (CF) is a chronic, multisystem autosomal recessive disorder due to CF transmembrane conductance regulator (CFTR) dysfunction which produces abnormally viscous secretions that impair organ function—predominantly in the lungs and pancreas. Presentation ranges from birth onward with chronic sinopulmonary disease, recurrent infections, pancreatic insufficiency, hepatobiliary disease, diabetes, and infertility. Diagnosis requires compatible features (or positive newborn screen) plus confirmatory sweat chloride, CFTR mutation analysis, or electrophysiology (EP) testing.

Epidemiology

Although most common in people with European ancestry, CF occurs in all racial groups.

Incidence

  • 1 in 3,200 White people
  • 1 in 10,000 Latin Americans
  • 1 in 10,500 Native Americans
  • 1 in 15,000 African Americans
  • 1 in 30,000 Asian Americans

Prevalence

  • ~35,000 in the United States and >180,000 worldwide (1),(2)
  • U.S. median predicted survival ~53.1 years (95% CI, 51.6 to 54.7) (1),(2)

Etiology and Pathophysiology

Abnormal CFTR (7q31.2) alters epithelial chloride/sodium transport, creating dehydrated mucus, impaired mucociliary clearance, infection-driven neutrophilic inflammation, and airway damage leading to bronchiectasis and progressive lung failure.

Genetics

CF is autosomal recessive with >2,000 CFTR variants. F508del is most common in the United States (~85.5%), followed by G542X (~4.5%) and G551D (~4.2%) (1). Disease severity is modified by other genes (e.g., meconium ileus risk), infections, GERD, and environmental exposures (e.g., smoke).

General Prevention

Preconception counseling

  • Preconception counseling: American College of Obstetricians and Gynecologists recommends universal preconception or early pregnancy CFTR carrier screening for all people, regardless of ancestry (3).
  • Newborn screening detects most new cases and enables earlier care with better lung and nutritional outcomes.

Commonly Associated Conditions

  • CF-related diabetes (CFRD): leading comorbidity (~29.2%) (1); progressive insulin deficiency with weight loss, declining lung function, or frequent exacerbations
  • Upper airway: chronic rhinosinusitis (15.2%) (1), nasal polyps
  • GI: pancreatic exocrine insufficiency with malabsorption of fat/protein/vitamins A, D, E, K; hepatobiliary disease (4.1%) (1); meconium ileus at birth; distal intestinal obstruction syndrome (DIOS); GERD.
  • Endocrine/bone/joints: osteoporosis (4.1%) (1), arthropathy
  • Reproductive: congenital bilateral absence of vas deferens (obstructive azoospermia) in males (9%) (1)
  • Psychosocial: depression

Pregnancy Considerations

  • Pulmonary disease may worsen during pregnancy.
  • Increased risks of preterm delivery, intrauterine growth restriction, and cesarean delivery.
  • Assisted reproductive technologies allow many men with CF to father children.

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