Genetic diseases are caused by gene mutations that lead to abnormalities or deficiencies of necessary proteins or enzymes. This, in turn, makes the tissues or organs dysfunctional. Some genetic disorders result from spontaneous mutations during embryonic development. Others are inherited from the parents who may or may not have the disease. Many genetic diseases are determined not only by genes, but environmental factors such as diet. Researchers are working to discover how genes contribute to such complex diseases as diabetes, asthma, cancer and mental illness.
Sickle Cell Anemia
Sickle cell anemia is the most common inherited blood disorder in the U.S., especially among African-Americans. Red blood cells, or RBCs, are damaged due to abnormal hemoglobin, the oxygen carrier of the body. This leads to lower-than-normal numbers of RBCs and problems with blood circulation. Symptoms become obvious during the first or second year of life. Some children can develop serious conditions as a result of this disease, including stroke and tissue damage.
Cystic Fibrosis
Cystic fibrosis is the most common fatal genetic disease in the U.S, and one of the most common inherited diseases among Caucasians, according to the National Institutes of Health, or NIH. Affected children have glands that produce large amounts of abnormally thick mucus that clogs ducts and collects in various organs, creating serious breathing and digestion problems. Symptoms that start in infancy include persistent coughing, wheezing, pneumonia and big appetite with little weight gain.
Tay-Sachs Disease
This fatal disease---most common among Ashkenazi Jews---is caused by a lack of an enzyme required to break down a fatty substance in brain cells, leading to a degeneration of the central nervous system. At about 6-months of age, children with Tay-Sachs disease slow down in development, lose vision and gradually lose other functions. They become mentally retarded and typically die by the age of 4 since there is no known treatment.
Duchenne Muscular Dystrophy
Duchenne muscular dystrophy is a disorder that affects mostly boys and is characterized by a progressive muscular weakness due to the lack of an essential muscle cell-protein. First symptoms appear early in life with children losing the ability to walk between ages 8 and 14. They may later die from respiratory and cardiac problems.
Fragile X Syndrome
Fragile X syndrome is the most common inherited form of mental retardation currently known, according to the NIH. It is caused by a defect in the X chromosome. It is more common and severe in boys, who can suffer from intellectual disability, severe mental retardation or autism.
