Down syndrome: Difference between revisions

 

Down syndrome, also known as trisomy 21, is a chromosomal disorder where an individual has an irregular number of chromosomes. The person will have three twenty-first chromosomes. This will cause the person to have distinct physical features and mild mental retardation. Close to 4000 children are born with Down syndrome each year. This means that one child out of every 700 to 1000 is born with Down syndrome. [http://www.nichcy.org/Disabilities/Specific/Pages/DownSyndrome.aspx] There is no possible way to prevent Down syndrome from occurring. Although it is more common after the age of thirty-five, a woman can still become pregnant with a Down syndrome child at any age. Although Down syndrome causes many health issues, both physical and mental, people who have the disease learn to live their lives to the fullest. Many people with Down syndrome live close to normal lives by attending school, working, and spending time with their family and friends.

British Physician, John Langdon Haydon Down, first classified Down syndrome in 1866. [http://caslater.freeservers.com/JLD.htm] During much of the nineteenth century, people with mental retardation were commonly known as Idiots. Dr. Down classified people with trisomy 21 as Mongolian Idiots. This term is now considered offensive towards those with Down syndrome and is not a politically correct term. [http://home.vicnet.net.au/~borth/DOWN1.HTM] Mongolism was renamed Down Syndrome after Dr. Down in the 1960’s.[http://www.ds-health.com/trisomy.htm] During the early twentieth century, people with Down syndrome were often the victims of Abuse. Many were institutionalized and were forced to undergo sterilization programs. In Nazi Germany, Many people with mental retardation, primarily those with Down syndrome, were cruelly murdered. Today, much has changed in the way people with mental retardation are treated. Many are given the chance to receive an education in public school and there are an increasing number of job opportunities available to people with mental disabilities. [http://www.bio-medicine.org/biology-definition/Down_syndrome/]

Down syndrome is a disease caused by an irregular number of chromosomes. There are three causes of trisomy 21. [http://www.ds-health.com/trisomy.htm]The most common is called nondisjunction. Nondisjunction happens during cell division. When a cell goes normally through meiosis, the chromosomes are divided evenly between the two daughter cells, but when no disjunction occurs, the chromosomes are split unevenly, giving one daughter cell extra chromosomes and the other one a less than normal amount. [http://www.wrongdiagnosis.com/n/nondisjunction/intro.htm] If and egg or sperm cell with an uneven number of chromosomes combines with a normal cell, the resulting fetus will have a third twenty-first chromosome, and therefore, will have Down syndrome.  

There are currently two types of tests available for women that will test for Down syndrome. The first tests are the screening tests. The screening tests estimate a women’s chance of giving birth to a Down syndrome baby, but they will not actually determine if a woman is pregnant with a Down syndrome fetus. These tests are often preformed via ultrasound. There is also a screening test that checks properties of the blood. The second tests can determine if a woman is pregnant with a Down syndrome fetus. These tests are the Diagnostic tests. There are three types of Diagnostic tests: Chorionic Villus Sampling (CVS), Amniocentesis, and Percutaneous Umbilical Blood Sampling (PUBS). [http://www.nads.org/pages_new/facts.html]  

The third Diagnostic test, Percutaneous Umbilical Blood Sampling, is done after twenty weeks of pregnancy. During this test, fetal blood is obtained from the umbilical cord. It is very similar to amniocentesis. It is often used when the other test have been inconclusive. [http://www.americanpregnancy.org/prenataltesting/percutaneousumbilical.html]

Ventricular septal defect, atrial septal defect, and patent ductus arteriosus are all forms of congenital heart disease were holes have formed in the heart. Ventricular septal defect is when a hole forms between the two lower chambers of the heart, also known as the ventricles. Ventricular septal defect is sometime treated by heart surgery, but often that isn’t needed because it is common for the hole to close on its own. [http://www.americanheart.org/presenter.jhtml?identifier=11066]  Atrial septal defect is the formation of a hole between the upper chambers of the heart, the atria.  Atrial septal defect is normally treated successfully with very little complications.[http://kidshealth.org/parent/medical/heart/asd.html]lastley, patent ductus arteriosus is a condition that occurs after the child has been born. In a normal child, the aorta and the pulmonary artery are connected by the ductus ateriosus. The ductus ateriosus closes soon after birth in a normal child, but in some cases it remains open. Patent ductus arteriosus can be treated with an operation, but sometimes the blood vessel will eventually close on its own.[http://www.nhlbi.nih.gov/health/dci/Diseases/pda/pda_what.html]

Other complex heart conditions that arise in children with Down syndrome involve Tetralogy of Fallot and Hypoplastic Left Heart Syndrome.  Tetralogy of Fallot is a complex heart condition. It is when the heart forms a Ventricular septal defect, pulmonary stenosis (a blockage to the lungs), and the aorta lies directly over the hole in the heart. This causes oxygenated and non oxygenated blood to mix together and flow throughout the body. This disease can be successfully treated with heart surgery. [http://www.americanheart.org/presenter.jhtml?identifier=11071] Hypoplastic Left Heart Syndrome is a serious condition where the heart remains underdeveloped. Blood is not properly pumped through the heart. The only treatment for this complex heart disease is a heart transplant or an operation.[http://www.americanheart.org/presenter.jhtml?identifier=1353]

A very common political debate is centered around Down syndrome and abortion. Abortion is the termination of a human life while it is still in the womb. The political debate that has risen up is whether it acceptable to abort a child because it has mental disabilities. Currently, almost ninety percent of Down syndrome children are aborted. It is extremely disturbing to know that so many people kill innocent children, just because they are different than the general population. Children with Down syndrome grow up to be functional adults that are capable of holding down a job and living with little assistance. [http://www.nytimes.com/2007/05/09/us/09down.html]

 

Down syndrome has many common physical characteristics. The following are some of the most common characteristics: the head is smaller than average, the face is flat, and the mouth is small. The slits of the eyes are narrow and have an epicanthal fold (a skin fold of the upper eyelid), and Brushfield spots are commonly seen in the iris. The ears are small and lower set on the head, and the neck is shorter than average. The length of the arms and legs are not proportionate to the size of the body.  The feet are wide and short towed. [http://www.downsyn.com/whatphys.php] Hands tend to be wide with short fingers. The hands will exhibit a single palmar crease, which is  commonly know as simian creases, which are single lines that run across the hand. [http://www.nlm.nih.gov/medlineplus/ency/article/003290.htm] Another common characteristic in people with Down syndrome is hypotonia. Hypotonia is low muscle tone of the body. Infants with hypotonia will appear floppy and loose in appearance, and they will have little control of their heads and limbs. If therapy is started at a young age for hypotonia, the muscles will develop more strongly. [http://www.ninds.nih.gov/disorders/hypotonia/hypotonia.htm]

 

 

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