Down's syndrome is basically a genetic disease that is caused by the presence of an extra chromosome. The chromosome that is defaulted in this syndrome is chromosome number twenty-one. It has been seen that Down's syndrome is one of the most common chromosome disease that is seen in humans. The major striking features of this disorder are physical and mental growth delay. It should be noted that the children appear small for their age and their actions and abilities are also slower than the children their age. It has been noted that Down's syndrome goes on to affect about one in every 800 hundred babies that are born in the United States. Even though the signs and symptoms are quite variable in all of the children, there are some particular signs that are characteristic of Down's syndrome. Children with Down's syndrome usually have an abnormally small chin, a flat nasal bridge, and slanting eye fissures on the inner corner of their eyes. Most of the children also have a larger than normal sized tongue which usually tends to stick out because of the small size of the oral cavity. Furthermore, it is seen that they have a short nick and white spots on the iris that are also called Brushfield spots. Most of the children with Down's are obese and are of a small stature. They have a common Mongolian look on their face as well. These children also have a simian crease present on their hand along with short fingers.

Causes

As mentioned earlier, Down's syndrome is basically a result of an extra copy of the genetic material on the 21st chromosome. It is noted that can either be the replication of the entire chromosome or it can be the replication of only some material on the chromosome. In order to understand the major mechanism behind the cause of Down's syndrome, it is only necessary for us to note down the basics of human genome replications.

Every cell in the human body consists of genes that either arrives from the mother of the father. All the chromosomes are basically condensed in the nucleus in every cell. Quantitatively speaking, the nuclear material consists of 46 chromosomes where twenty three of the chromosomes come for the mother and twenty three of the chromosomes come from the father.

Trisomy 21 is the most common cause of Down syndrome. Normally, the chromatin material divides and is able to condense 23 chromosomes in every gamete. On fertilization, when the gametes fuse, the end result is an embryo consisting of 46 chromosomes. In Down's syndrome, there is a problem in the cell division which is known as nondisjunction. Due to this reason, one of the sperm or egg that goes for fertilization has an extra copy of the chromosome 21. An interesting thing to note is that 88% of the times, this nondisjunction arise from the mother's egg cell rather than the father's sperm.

There are two other causes present of Down's syndrome known as Mosaic Down Syndrome and Translocation Down Syndrome. The Mosaic Down Syndrome is a very rare form where children only have some cells with the extra copy that was mentioned earlier. As it would be expected, the disease would take a worse form if all the cells in the body are affected. Even though this is a milder film, Mosaic Down's Syndrome is also caused by abnormal cell division and subsequent fertilization. The translocation Down's syndrome is when Chromosome number 21 becomes translocated to another chromosome. This event is likely to occur either before or at conception. Even though these children have the normal two chromosomes 21, there is additional material present on chromosome number 21.

There are a lot of debates regarding what the actual cause of Down's Syndrome is. It was noted that there are many risk factors for Down's syndrome. One of the most common risk factor is increased maternal age. It was noted that as a woman's age increases, the eggs are likely to get defected. Older eggs do have an increased chance of errors during chromosomal division. It is seen that when a woman reaches 35, the risk of her conceiving a child with Down Syndrome is one in four hundred (Egen et.al, 2011) . Similarly, ten years later, the risk increases to one in thirty five. Furthermore, it was noted that when a woman has one baby with this disorder, there are increased chances of having another child with this disease. A lot of people also think that the parents have certain traits that make them more likely to a genetic translocation. Therefore,...

According to the CDC, there are six thousand children born everywhere with Down's Syndrome. If we look at the overall causes of mental retardation, then Down's Syndrome counts for basically one third of all the severe and moderate handicaps in school aged children. According to the National Down Syndrome Society, there are more than four hundred thousand people living with Down's Syndrome.
As it was stated earlier, the occurrence rate of Down 'syndrome tends to increase with maternal age. If the mother is around the age of twenty five, the occurrence rate is about one in thirteen hundred. Furthermore, five years later, the chances of having a baby with Down's syndrome increase to about one in nine hundred. A more detailed discussion on age and increased chances of Down's syndrome has been carried out in the previous section.

There are is predisposition of a certain ethnic of economic group for getting this disease. Even though there is no race predilection, African-Americans affected with the disorder tend to have a shorter life span than white patients affected with Down's. If we look at the two sexes, then it is seen that both are affected with the same rate. The male to female ratio is a bit high in newborns with Down's Syndrome. It was noted that for the females who have Down Syndrome, there are high chances of them giving birth a child with Down's Syndrome. As it would be known, most of the fetuses with a congenital anomaly do abort spontaneously. Regardless, there are fifty percent changes that a baby of a person with Down's Syndrome would be affected with the disorder as well.

The prognosis and the disease progression of this disease basically depend on the problems or complications that the child develops over the years. Back in 1910, a child born with Down's Syndrome would not survive more than nine years. Due to increased researches and interventions on this topic, it has been noted that 80% of the people with this disorder go on to live past fifth decade of their life.

Signs and Symptoms

As mentioned earlier, there are many distinct facial and physical features that accompany Down's syndrome. Therefore, some of the earliest signs appear when the baby is born. The baby would have a flat face that has a depressed nasal bright. The ears of the baby can be folded over at the top. Furthermore, the head, nose, feet and hands would be smaller than the normal baby's. The features of having a large protruding tongue and white spots on the iris have already been discussed above. Other apparent features include short hands with a one single crease in the palm. Another notable feature is that there is increased space between the first and the second toe.

It is noted that children with Down's Syndrome appear very floppy at birth because they have decreased muscle tone which is known as hypotonia. Along with hypotonia, these children also have poor muscle tone and loose joints. Most of the time, the facial features of the baby alert the parents that there is something wrong with their child. As the child grows, he or she attains his developmental milestones very late. These children tend to have a blank expression and don't develop the social milestones that a normal baby would have developed.

Furthermore, parents notice retardation as the child grows older. Children who are affected with Down's Syndrome tend to have a speech delay. They do require assistance such as a speech therapy y in order to express themselves in a proper way. Furthermore, they tend to be behind in their gross motor and fine motor skills. The normal age of a child to start walking is about fifteen months .However, children with Down Syndrome will begin to walk at the age of four on average.

Detection and Diagnosis

There are two ways in which health care providers go onto detect and diagnose Down's Syndrome. They can either check for the disease before the child is born or after the child is born. AT first, all women who are pregnant are recommended to get a screening test. During pregnancy, the mother can be screened for Down's Syndrome through ultrasound or testing maternal serum for certain markers. It has been…