Cystic Fibrosis (CF)
What is Cystic Fibrosis
Cystic Fibrosis (CF) is a Mendalian disorder also known as a genetic disorder that affects the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene. CF has affected children and adults, and can become chronic, or lifelong. Currently, there is no cure for CF, however, there is prior testing to help with early diagnosis and treatments to ease the symptoms. The life expectancy of an individual with CF has improved and increased over the years.
Cystic Fibrosis Symptoms
- Coughing
- Wheezing
- Stuffy nose
- Lung infections
- Inability to gain weight
- Fatty stools
Why Does It Occur?
Water and electrolytes follow Cl- through the CFTR channel. These fluids are typically thin and slippery. In CF individuals, the CFTR channel is defective, which leads to thick and sticky mucus in the lungs. The accumulation of mucus can block the tubes, ducts, and/or passageways in the body further causing life-threatening lung infections or malabsorption.
Asthma is an obstructive pulmonary disease in which the airways swell and narrow. In addition to the resistance, the collection of mucus produced causes difficulty breathing.
Other possibilities that CF could lead to are pancreatitis and intestinal obstruction. Inflammation of the pancreatitis prevents enzymes from reaching the intestines, therefore there is an elevated level of pancreatic lipase and amylase in the blood. The inflammation damage to the acinar pancreatic cells prevents the breakdown and digestion of food in the intestines.
How Does It Occur?
70% of CF cases are caused by a 3 nucleotide deletion. The deletion results in a loss of amino acid, phenylalanine, in the CFTR protein. 30% of other cases are explained by other CFTR alleles. There are over 1,700 known Cystic Fibrosis causing alleles.
Carriers
- High carriers: 91% Northern European Caucasian
- Low carriers: 81% African American
- Very low carriers: 54% Non-Japanese Asians American. Most likely due to a rare mutation.
Diagnosing Cystic Fibrosis
Includes a test and clinical evaluation at a CF Foundation-accredited care center. The majority of CF patients are diagnosed by age 2.
- Sweat Chloride Test: measures amount of Cl- in sweat
- CF individuals have elevated Cl- in their sweat
- Genetic Test: diagnose genetic disorders
- Molecular Test: identify the presence of disease-causing variants
- Prenatal Genetic Test in 1st trimester: blood test
- Newborn Screening: blood test for early detection
- Carrier Testing: determine if a person is a carrier for a specific autosomal recessive disorder
- CF is an autosomal recessive disorder
- Induced Pluripotent Stem Cells: only effective for monogenic diseases