Sickle Cell Disease example essay topic

Cystic Fibrosis is a disorder where the exocrine glands secrete abnormally thick mucus, leading to obstruction of the pancreas and chronic infections of the lungs, which usually cause death in childhood or early adulthood. Some mildly affected patients may survive longer. Doctors can diagnose the disease by testing the patients perspiration because people with Cystic Fibrosis have high amounts of salt in their perspiration. Those with respiratory infections are treated with antibiotics, with aerosols that relieve constriction of the airways and liquefy the thick mucus, and by physical therapy to help patients cough up the obstructing secretions. Patients with pancreatic insufficiency can take pancreatic enzymes with meals. Intestinal obstruction, which occurs primarily in infancy (me conium ileus), may require surgery.

The liver may also be seriously affected by Cystic Fibrosis. No cure for the disease has yet been found. Cystic fibrosis is the most common inherited fatal disease of Caucasians, occurring about once in every 2500 births. If both parents carry the gene responsible for the disease, they have a one-in-four chance of having an affected child. In 1989, the gene responsible for cystic fibrosis was identified on chromosome 7 (out of 23 chromosomes).

Since that time more than 200 different mutations in the cystic fibrosis gene have been described, and tests have been developed to detect the most common alterations. These tests can identify unaffected carriers of the disorder. Sickle-Cell Anemia Sickle-Cell Anemia, also called sickle-cell disease, is a hereditary condition where hemoglobin, an oxygen-carrying protein in the blood, is altered, leading to periodic interruptions in blood circulation. All over the world. the disease is found predominantly in blacks, of whom approximately 1 in 400 are affected; it mainly occurs in the US, in the Middle East and the Mediterranean area. Symptoms of the condition appear at about six months of age and may include enlargement of the abdomen and heart and painful swelling of the hands and feet.

In adolescence, sexual maturation may be delayed. The disturbances in blood flow associated with the disease also dispose affected persons to infections and leg ulcers. These symptoms are due to the altered hemoglobin, which changes shape when the amount of oxygen in the blood is reduced for any reason. The red blood cell in which the hemoglobin is contained changes its shape as well, from round to crescent (sickle shaped).

The sickle-shaped red cells interfere with normal blood flow by plugging up small blood vessels. Sickle-cell anemia occurs when an individual inherits a sickle-cell gene from each parent. Programs have been initiated to detect carriers, who do not themselves show the trait; such carriers are informed that a child resulting from the union of two carriers runs a one in four risk of having sickle-cell disease. Therapy for sickle-cell anemia is largely symptomatic.

Preventive administration of penicillin to affected children by the age of four months greatly decreases mortality from infections. For this reason, routine screening of newborns for sickle-cell anemia is currently carried out in more than 40 states within the United States. Down Syndrome Down Syndrome, which used to be called mongolism, is a congenital malformation accompanied by moderate to severe mental retardation, is caused by a chromosomal abnormality. People with Down syndrome are often short in height and have a small, round head with a high, flattened forehead and split, dry lips and tongue. A typical feature is a fold of skin, fold, on either side of the bridge of the nose. The palms show a single transverse crease and the soles have a straight crease from the heel to the space between the first and second toes.

These people are also subject to congenital heart defects and tend to develop leukemia. Their intelligence quotient, IQ, usually ranges between 20 and 60, but with early intervention and proper education, some people reach higher levels. The overall incidence of Down syndrome is approximately one in 700 births, but the risk varies with the age of the mother. The rate of Downsyndrome in children born to 25 year old mothers is approximately 1 in 2000, but the risk increases to 1 in 200 for 35 year olds and more than 1 in 40 for women older than 40 years. Prenatal tests such as amniocentesis and chorion ic villus sampling can be used to detect the chromosomal abnormality causing Down syndrome. In addition, maternal blood tests can suggest the presence of a fetus with Down syndrome when levels are lower than usual, or when levels of unpaired estriol and human are abnormal.

The chromosomal abnormality involved in most cases of Downsyndrome is 21, or the presence of three copies of the 21st chromosome. As a result, the affected person has 47 chromosomes in all body cells instead of the normal 46, although how this causes the condition's symptoms is not yet known. Scientists assume that the reason for the abnormal chromosomal combination is the fertilization of a novum having 24 chromosomes by a sperm with a normal assortment of 23, but they have also found that the sperm can carry the extra chromosome a swell. The abnormal ovum or sperm is derived from germ cell in which the pair of 21st chromosomes holds together and passes into the same sperm or ovum instead of separating. In the type of Downsyndrome called translocation, the extra chromosome 21 material is attached to one of the other chromosomes; when some, but not all, of the body's cells carry an extra chromosome 21, the condition is a type of Down syndrome.

Down syndrome is not yet responsive to medical treatment, but better medical care of the accompanying disorders and infections now results in an almost normal life span instead of the previous life expectancy of about 14 years. The severely retarded may still be institutionalized, but many Down syndrome children are raised at home, where their full potential can be developed. Although, with an average mental age of about eight years, they continue to need a protective environment, many adults with Down syndrome work in sheltered workshops; some hold regular jobs in business and industry.