What is Down syndrome?
Down syndrome also known as Trisomy 21 is a chromosomal condition where a person possesses extra genetic material that is: an extra complete or fractional duplicate of chromosome 21. It is one of the most common birth defects. It affects 1 in 800 to 1 in 1000 live born infants. Close to half of all affected children develop heart defects right from birth (Goldstein 71).
Causes
Down syndrome is typically caused by non-disjunction; when one of the three types of abnormal cell division involving chromosome 21 occurs. Non-disjunction occurs when a pair of chromosomes fails to detach during sperm or egg formation. After the egg fuses with a sperm to form an embryo, instead of ending up with two copies of chromosome 21, that embryo ends up with three copies. That extra chromosome is copied in each cell of the baby’s body. It is a disorder that cannot be passed from an individual to another. It is therefore a genetic disorder that we inherit from our parents when there is a complication in the pregnancy.
Symptoms
People with Down syndrome have mental retardation, to a large extent, they have a certain degree of learning disability, they have a flat face, abnormally shaped ears, a small broad nose, slanting eyes with tiny folds off skin in the corners, learning difficulties, poor muscle tone (hypotonia) in infancy and a characteristic facial appearance. Also, persons with Down syndrome have an increased risk for digestive problems including celiac disease or gastroesophageal and hair loss. In other cases, people with Down syndrome have activity of hypothyroidism (the thyroid gland) an organ in the lower neck which produces hormones. Affected individuals experience cognitive delays although to some extent, intellectual disability is normally mild to moderate. Delayed behavioral and developmental problems are often reported in children, for instance, delays in language and speech is common. Studies show that individuals with Down syndrome often experience a steady decline in (cognition) thinking ability mostly when they age. Children with Down syndrome have exclusive individual traits that they have inherited from their parents. These children can resemble their father, mother, aunt, sister, grandmother or any other member of the family. These children with Down syndrome have diverse traits for example; some are stubborn while others are easy going.
Possible Complication
Complications that could result from Down syndrome include;
- Eye problems
- Hearing loss
- Air blockage during sleep
- Heart problems
- Frequent ear infections and other increased infections in the body
- Weakness of the back bones at the top of the neck
Inheritance
Down syndrome is not really inherited as most people presume. Instead, it is caused by a mistake in cell division precisely during the development of the embryo, the egg or sperm. It is actually the only form of the disorder than can be passed from parent to child. Chances of passing on the translocation entirely depend on the parent’s sex carrying the arranged chromosome 21. This means that, if the mother is the carrier, the risk is between; 10% to 15% and if the father is the carrier, the risk is less to about 3% (Park 114).
Diagnosis
There are a number of ways that Down syndrome can be diagnosed. First, Down syndrome can be diagnosed in infancy based on the particular characteristic clinical findings. If a doctor suspects Down syndrome, a chromosome analysis which is also the genetic test is performed on skin or blood sample to look for (trisomy 21); the extra chromosome 21. There are also two types of tests check for Down syndrome during a woman’s pregnancy; diagnostic tests and screening. A screening test identifies a mother who is most likely carrying a baby with Down syndrome. For this, the Triple Screen and the Alpha-Fetoprotein Plus are the most common. They measure levels of particular substances in the blood. On the other hand, ultrasound that uses sound waves to view the mother’s uterus allows the physician to examine the fetus for physical signs of Down syndrome while in the womb.
In order to confirm positive results that have been identified in a screening test, the following tests can be performed; percutaneous umbilical sampling (PUBS), chorionic villus sampling (CVS) and amniocentesis. In all these tests, a sample is taken from amniotic fluid, placenta or from the umbilical cord to determine if the baby has an extra chromosome 21 and to examine the baby’s chromosomes.
However, if Down syndrome is not diagnosed in the womb; a physician can identify it by its distinctive facial features after the baby is born. This process ends when the diagnosis is confirmed with an examination of the chromosomes of the baby which is also known as a karyotype. The presence of the extra number 21 chromosome interrupts normal growth and normal course of development causing distinctive clinical features of Down syndrome. Selected people have Down syndrome because some part of chromosome 21 is appended to another chromosome at or before conception. These individuals have additional material from chromosome 21 which is also attached to another chromosome and they also have two copies of chromosome 21 (Bremner 233).
Can Down syndrome be prevented?
Today there is no cure for Down syndrome. Scientists are not quite certain how to prevent the chromosomal which is the root cause of Down syndrome. There is no reason whatsoever to believe that parents can cause or prevent their baby’s birth with Down syndrome. Conversely, recent studies show that certain women who have delivered babies with Down syndrome initially had abnormalities in how their bodies’ metabolism processes interfere with B vitamin folic acid. Certain studies depict that certain high dose vitamins that are administered to children with Down syndrome lessen the mental retardation and enhance the mental performance. Since there are no medical studies proving that this actually works, new families should take the initiative of talking to the doctor or physician and the National Down Syndrome Congress to get to now various ways in which Down syndrome affects the body and to also learn other important aspects regarding Down syndrome that could help in raising children with Down syndrome.
Treatment
Treatment for Down syndrome is entirely based on an individual’s intellectual challenge and problems. Apparently, no cure exists for Down syndrome. However, speech therapy and physical therapy can assist individuals with this disorder to develop more normally. For instance, the majority of the babies with Down syndrome have deprived muscle tone and this is hard for them to walk and roll over, these problems can be solved through the use of physical therapy. Additionally, corrective surgery and screening for common medical problems that are associated with Down syndrome can pretty much improve one’s quality of life. Subsequently, enriched environments increase their capacity significantly to lead a significant life. Today many adults with Down syndrome have jobs and live normal independent lives.
Interesting Facts about Down syndrome
Subsequently, Down syndrome is actually the only trisomy that is compatible with life. There are only two other trisomies that have to date been observed in babies born alive, although these babies possessing these trisomies only have at most 5% chance of surviving more than one year. Arguably, in 92% of all Trisomy 21 cases, the extra chromosome appears from the mother’s egg and from the father’s sperm. Down syndrome affects 1 out of every 800 to 1,000 babies and it is the most common genetic disorder that is caused by chromosomal abnormalities (Pui 503).
Conclusion
Human genetic disorders come about due to certain defects of persons of genetic materials. Down syndrome is not really inherited as most people presume. Instead, it is caused by a mistake in cell division precisely during the development of the embryo, the egg or sperm. Depending on the causes, human genetic disorders vary in many ways. They are mostly caused by mutation of DNA and genes and there are four types: chromosomal, single-gene, mitochondrial and multifactorial. Every type of disorder has different cause. For instance, the chromosomal disorder is brought about by mutation of chromosomes. It is through abnormalities of chromosomes and genes that human genetic disorders occur. Certain diseases such as cancer result from genetic disorders although they can also occur due to environmental factors. Majority of these disorders are very rare and they affect selected persons. Today persons with Down syndrome have jobs and live normal independent lives.
Works Cited
Pui, Ching-Hon. Childhood Leukemias. Cambridge, UK: Cambridge University Press, 2012. Print.
Bremner, J G, and Theodore D. Wachs. The Wiley-Blackwell Handbook of Infant Development: Vol. 2. Chichester, West Sussex: Wiley-Blackwell, 2010. Internet resource.
Goldstein, Sam, and Cecil R. Reynolds. Handbook of Neurodevelopmental and Genetic Disorders in Children. New York: Guilford Press, 2011. Print.
Park, In-Hyun, et al. "Disease-specific induced pluripotent stem cells." cell 134.5 (2008): 877- 886.
