This paper provides a comprehensive overview of cystic fibrosis (CF), a genetically inherited disorder caused by a defective gene that leads to the accumulation of thick, sticky mucus in the lungs and digestive system. The paper examines CF's clinical presentation across age groups, its autosomal recessive inheritance pattern, and the role of the CFTR gene in disease severity. It also reviews epidemiological data, standard diagnostic tests such as the sweat chloride test and IRT screening, and current treatment strategies including antibiotics, enzyme therapy, airway clearance, and nutritional support. The paper concludes with a brief discussion of prognosis and recent advances in CF research.
Cystic fibrosis (CF) is a genetically inherited disorder caused by a defective gene that results in the body producing abnormally thick and sticky fluid called mucus. This mucus builds up in the breathing passages of the lungs and in the pancreas, the organ that helps to break down and absorb food (PubMed Health, 2011).
Reports indicate that millions of Americans carry the defective cystic fibrosis gene; however, most do not have any symptoms. This is because a person with cystic fibrosis must inherit two defective CF genes, one from each parent. An estimated 1 in 29 Caucasian-Americans carries the CF gene. The disease is the most common deadly inherited disorder affecting Caucasians in the United States and is more prevalent among those of Northern or Central European descent (PubMed Health, 2011).
The majority of children with cystic fibrosis are diagnosed by the time they are two years of age. However, a small percentage are not diagnosed until they are 18 years of age or older; these individuals generally have a milder form of the disease.
Symptoms of cystic fibrosis in infants include the following:
(1) Delayed growth; (2) failure to gain weight normally during childhood; (3) no bowel movements in the first 24 to 48 hours of life; and (4) salty-tasting skin (PubMed Health, 2011).
Bowel-related symptoms include the following:
(1) Belly pain from severe constipation; (2) increased gas, bloating, or a belly that appears swollen (distended); (3) nausea and loss of appetite; (4) stools that are pale or clay-colored, foul-smelling, contain mucus, or that float; and (5) weight loss (PubMed Health, 2011).
Lung-related symptoms include the following:
(1) Coughing or increased mucus in the sinuses or lungs; (2) fatigue; (3) nasal congestion caused by nasal polyps; and (4) recurrent episodes of pneumonia (PubMed Health, 2011).
Additional symptoms in someone with cystic fibrosis include:
(1) Fever; (2) increased coughing; (3) increased shortness of breath; (4) loss of appetite; (5) more sputum; and (6) sinus pain or pressure caused by infection or polyps (PubMed Health, 2011).
Later-life symptoms include:
(1) Infertility in men; (2) repeated inflammation of the pancreas (pancreatitis); and (3) respiratory symptoms (PubMed Health, 2011).
Cystic fibrosis is described as an inherited multisystem disorder of children and adults, characterized chiefly by obstruction and infection of the airways and by maldigestion and its consequences (Easy Pediatrics, 2012). CF is inherited as an autosomal recessive trait. The CF gene codes for a protein of 1,480 amino acids called the CF transmembrane conductance regulator (CFTR) (Easy Pediatrics, 2012).
Four long-standing observations are considered pathophysiologically important:
(1) Failure to clear mucous secretions; (2) a paucity of water in mucous secretions; (3) an elevated salt content of sweat and other serous secretions; and (4) chronic infection limited to the respiratory tract (Easy Pediatrics, 2012).
Additionally, there is a greater negative potential difference across the respiratory epithelia of CF patients compared with control subjects. Aberrant electrical properties have also been demonstrated for CF sweat gland duct epithelium. The membranes of CF epithelial cells are unable to secrete chloride ions in response to cyclic adenosine monophosphate (cAMP)-mediated signals, and — at least in the respiratory tract — excessive amounts of sodium are absorbed through these membranes (Easy Pediatrics, 2012).
"CFTR mutations, F508 deletion, and carrier inheritance"
"Incidence rates and survival data from longitudinal study"
"Diagnostic tests and lung, bowel, and home care treatments"
"Life expectancy and recent research developments"
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