Genetic diseases are caused by abnormalities in the human genome. We get these abnormalities from the genes given to us by our parents. These defects can affect one or many genes or even be at the level of the chromosome. Having noticeable symptoms from an abnormality can depend on how important the gene is for overall function of the human body and if you inherited this abnormality from both or just one parent.
Sickle Cell Anemia
The National Institutes of Health states that sickle cell disease is a type of anemia (not enough red blood cells) caused by a defect in a gene that is responsible for the shape of the blood cells. Instead of a round shape, the blood cells are more like a C shape (sickle shape). In people with this disease, some of the blood cells are normal, and others are in the sickle shape. The odd shape of the cells causes them to not move as well through the veins and form clumps and "traffic jams" for the healthy blood cells. These clumps can block blood flow and cause organ damage from the lack of blood flow. In addition to potential organ damage, most people with this condition will feel bouts of fatigue.
This gene defect can be mild to severe, and symptoms depend on the number of abnormal cells. Sickle cells do not live as long as normal blood cells. According to the National Institutes of Health, a healthy red blood cell lives for 120 days, but a sickle cell may only last for 10 to 20 days; thus, the anemia is caused by the short life of the cells.
Cystic Fibrosis
According to the Cystic Fibrosis Foundation (CFF), cystic fibrosis a commonly inherited disease caused by a defect in a gene that makes protein. This protein product causes the body to make an abnormally thick and sticky type of mucus. The mucus goes on to clog the lungs and cause infections within the airway. Additionally, this mucus can clog the ducts in the pancreas that releases enzymes to help with digestion. Cystic fibrosis is a lifelong problem, and according to the CFF, most people with this disease only live to 37 years of age.
Down Syndrome
Down syndrome is a genetic disorder caused by problems not with the DNA but at a higher level, in that of the chromosomes. Those with Down syndrome have an extra chromosome. The National Down Syndrome Society states that one in every 733 babies is born with Down syndrome, and it affects people of every ethnic background. Those with Down syndrome have commonly recognized signs, including upward slant to the eyes, a single line across the palm called a simian line, and decreased muscle tone and height. Not all of these physical signs have to be present with the disease.
In addition to physical characteristics, those with Down syndrome can also be slow cognitively and are at risk for other problems with their health from heart problems to thyroid problems. Just like any one else, though, medicines can be taken for the associated health problems. According to the National Down Syndrome Society, the life expectancy has increase from 25 years old to 60 years old in the past 25 years.
