Genetic disorders are caused by an abnormality in an individual’s DNA sequence. This can be because of a mutation in one gene, mutations in multiple genes, or mutations and environmental causes. They are inherited (passed down from the parent to child) and are called hereditary mutations. Hereditary mutations are carried in the DNA of the reproductive cells. When the reproductive cells combine to produce offspring, the mutation will virtually be in all of the cells of the offspring’s body.
Level 1- Single-Gene Disorders:These disorders are the result of a single gene being altered ormissing. Level 2- Chromosome Abnormalities:These disorders are the result of entire chromosomes or largesegments duplicated, altered or missing. Level 3- Multifactorial Disorders:These disorders are the result of mutations in multiple genes andalso environmental causes.
Cystic fibrosis (CF) is a single gene genetic disorder that affects the respiratory and digestive system. Individuals with cystic fibrosis have inherited a defective gene called CFTR (cystic fibrosis transmembrane conductance regulator). This gene normally produces a protein that helps sodium in and out of cells. Cystic Fibrosis is a recessive disorder, which mean both parents must pass on the gene for their offspring to get the disorder. If only one parent passes on the gene and the other does not, the child will not have the disorder but will be a carrier of the gene. 1 in 25 Canadians carry the gene.
Cystic fibrosis affects children and youngadults. The disease mainly affects the lungsand the digestive system. A proteinProduced in the CFTR gene does not workproperly and causes mucus to build upoutside of the cell. It effects the lungs themost, due to the thick mucus it causesdifficulty breathing. It also makes itdifficult to clear bacteria causing infection. Mucus builds up in the digestive system aswell, making it difficult to absorb nutrients.
Many cases were misdiagnosed as whooping cough, chronic bronchitis or pneumonia. CF became more well known in the 1700’s due to the German expression “A child whose forehead tastes like salt when kissed will soon die.” Throughout the decades: 1930’s- said to be first discovered, thought to be a Vitamin A deficiency. 1940’s- doctors Sidney Farber and Harry Shwachman noticed the secretion of mucus. 1950’s- used a sweat test to help diagnose CF. 1960’s- organized research for CF began. 1970’s- advocated high-fat diets. 1980’s- found more ways to help treat the disease. 1990’s- gene replacement therapies began to help treat. 2000’s- research continues for a cure. Life expectancy for an individual with CF is around 40.
Difficulty breathing Rattling cough that expels mucus Lung infections Unable to gain weight Difficulty digesting Salty tasting skin
Medications Medications are used to treat lung disease Many are inhaled using a nebulizer Medications used are: Mucolytics, which loosen lung mucus Bronchodilators, which expand the airways Steroids, which decrease inflammation Antibiotics, fight infections Chest physical therapy Considered standard therapy Used to clear mucus from the lungs Person is clapped on the back
Nutrition Good nutrition High-calorie diet Vitamins Pancreatic enzymes Pancreatic enzyme supplements, taken with everything consumed, help absorb nutrients Transplantation Transplants are used for end-stage disease. The transplants used are: Double-lung transplant Heart-lung Liver
Gene therapy is an experimental technique that uses genes to treat diseases. Gene therapy can replace a mutated gene or inactivating a mutated gene. It is promising but risky. It needs more research to see if it is safe. Gene therapy has been used for cystic fibrosis, in which the healthy CFTR gene is inserted into the lung cells