Down syndrome and Trisomy 21

Dear Readers,

Today’s weekend health article is all about Down syndrome. Lots of our readers have written to request further explanation of what is Down syndrome and how does it occur. A lot of people know that older mothers are at a much greater risk of having children with Down syndrome. So, as many women are having children at a much later stage in their life, it is only normal that they would want to ask this question and therefore, get more information about Down syndrome. That is what this article will try to do.

What is Down syndrome?

Down syndrome was named after John Langdon Down (1828-1896), who was the first physician to identify it, way back in 1866.

As quoted by Mothers 35 Plus, Down syndrome occurs in about 1 out of every 700-900 live births worldwide to mothers of all social, economic and racial groups, and is the most common genetic cause of developmental disability.

According to the NHS Down syndrome is a chromosomal disorder caused by an error in cell division and the most common form produces an additional third chromosome 21, or "Trisomy 21" (it is also known in some countries as Trisomy 21). There are three forms of Down's syndrome, with 94% being affected with Trisomy 21.

The other two are:

Trans location, which is caused when a piece of chromosome 21 attaches itself to another chromosome in a cell. It affects around 4% of people with Down's syndrome. The symptoms of Translocation Down's syndrome are similar to those of Trisomy 21, but in rare cases it may be possible for a parent to pass Trans location Down's syndrome on to their child.

Mosaicism is the least common type, affecting around 2% of people with Down's syndrome. Only some of the cells have an extra copy of chromosome 21. People with mosaic Down's syndrome may experience less delay with some aspects of their development.

The WebMD explains that when a newborn baby is born with the syndrome, it may have some disadvantages such as, mental retardation as well as characteristic physical features. 

The main physical characteristics of someone with Down syndrome is: Slanting eyes, flatness of head, shortness of neck and nose, as well as a creasing of palms. Other characteristics include: poor muscle tone and having toes widely spread apart.

The features of a newborn baby having Down syndrome are shown in figure 1 below from “Redefining the Face of Beauty.”

Figure 1. Features of a child having Down syndrome

Child affected with Down syndrome

To better understand the above features; let’s take a closer look at some pictures of children with Down syndrome, through the years to teenage hood below in Figure 2,3 and 4.

Figure 2.

Source: Deposit photos

Figure 3.

Source: eHow

Figure 4.

Source:  Jessie Mano’s Blog

Each of the above pictures clearly show the physical features described above.

With this disorder I have also outlined in this article other health problems that can occur.

Many kids with Down syndrome are born with heart defects. This means that their hearts develop differently and don't work as they should, however, these problems can be fixed by surgery. Some babies may have intestinal problems that also require surgery to fix.

Kids with Down syndrome are more likely to get infections that affect their lungs and breathing. When they do get infections, they often last longer. They may have eye or ear problems or digestion problems like constipation. Some may develop leukemia, a type of cancer. Each person with Down syndrome is different and may have one, several, or all of these problems.

Kids with Down syndrome also tend to grow and develop more slowly than other children do. They may start walking or talking later than other babies. Special help, such as physical therapy and speech therapy, can give kids a boost with their walking and talking skills.

What causes Down syndrome?

When you examine a new born baby or fetus to see if it has any additional problems, doctors look at what is called their karyotype. This is simply a picture of a person's chromosomes in a karyotype with Down syndrome below.

Figure 5. Notice that there is an extra chromosome next to another chromosome in pair 21

Most people have 23 pairs of chromosomes, for a total of 46. But a baby with Down syndrome has an extra chromosome (47 instead of 46) or one chromosome has an extra part. This extra genetic material causes problems with the way their bodies develop.

Why are older women at risk of having children with Down syndrome?

The article in, My Child without Limits stated that doctors have found out that it is more likely for an older mother to have reproductive cells with an extra copy of chromosome 21. Therefore an older mother is more likely to have a baby with Down syndrome than a younger mother. The likelihood of Down syndrome continues to increase as a woman ages, so that by age 42, the chance is one in 60 that a pregnant woman will have a baby with Down syndrome and by age 49, the chance is one in 12. 

Because the chances are so high of having a child with Down syndrome, many Doctors recommend that women over age 35 have pre-birth testing for the condition. This is called Amniocentesis. Testing the baby before it is born to see if he or she is likely to have Down syndrome allows parents and families to prepare for the baby’s special needs. To find out more information on the Amniocentesis test, just look at Baby center.

So readers. I hope my article helped you find out all about Down syndrome, and I have answered all the questions that you had in your mind. If you need more information that I did no cover in the news story please click on the link below.

Kids health

Matija Kondic