How familiar are you with people with Down Syndrome? Do you consider them intelligent individuals or believe they have low IQs?
There is a nucleus in every human body cell where genetic materials are kept in genes, which carry the codes that are responsible for all of our traits and have rod-like structures called chromosomes.
The normal nucleus of each cell has 23 pairs of chromosomes, which we get half of them of each parent. Down syndrome happens when someone has a full or an extra copy of chromosome 21.
According to different research, the average IQ of a person with DS ranges between 30 and 70. If you want to know more about the average intelligence quotient of people with Down Syndrome, keep reading!
Definition of IQ
IQ is the short form of Intelligence Quotient and is a measurement of individuals’ reasoning abilities; and is supposed to determine how well a person can receive and analyze information to answer questions, make predictions, or solve problems.
IQ scores are obtained from a set of standardized tests or subtests that are designed to evaluate human intelligence.
The final result of the IQ test is transformed to a normal distribution with a mean of 100 and a deviation of 15 to determine the final IQ score.
Finally, the normal IQ level for two-thirds of the population is between 85 and 115, and almost 2% score above 130 and below 70.
What Is Down Syndrome
Down Syndrome, also known as trisomy 21, is a genetic disorder in which an individual has an extra chromosome.
As mentioned, chromosomes are small packages that have the genes in themselves and determine how a baby’s body forms and functions during pregnancy and after birth.
Normal babies will be born with 46 chromosomes; however, those with Down Syndrome would have an extra copy of one chromosome, which is chromosome number 21.
The medical term for such babies with an extra chromosome is “trisomy,” which is also known as Trisomy21.
This extra copy of genes causes a lifelong disorder and changes how a baby’s body and brain form and function.
Different Types of Down Syndrome
There are three different types of Down Syndromes, which many of us don’t know about, and people can’t tell the difference without looking at the chromosomes.
1- Trisomy 21
This is the most common type of DS, and almost 95% of people with this disorder have Trisomy 21.
In short, the body cells in people with Trisomy 21 have three separate copies of chromosome 21 instead of two copies.
2- Translocation Down Syndrome
Almost 3% of people with Down Syndrome have this type of DS, and it happens when an extra part of chromosome 21 is present, but it is attached to a different chromosome, and that is why it is called “trans-located.”
3- Mosaic Down Syndrome
Mosaic means combination or mixture, and this type is not very usual and affects almost 2% of the DS community.
People with this type of Down Syndrome have three copies of chromosome 21 in some of their cells, while they have the normal two copies in other cells.
As said before, you can not tell the difference between these three types of DS easily because people with Down Syndrome mostly look like each other regardless of the type.
What Causes Down Syndrome in People
Now that you know different types of Down Syndrome, note that all people with DS have an extra chromosome 21 in all or some of their body cells, regardless of the type of Down Syndrome.
The answer to what causes the extra or partial chromosome is still unknown; however, the age of the parents is the only factor that scientists believe increases the chances of having a baby with DS.
Moreover, there is no exact research that shows whether the age of parents is the only factor or if Down Syndrome is caused by environmental factors or parents’ activities and habits during or before pregnancy.
Finally, note that the additional or partial copy of chromosome number 21 can be from both mothers and fathers; almost 5% of cases show the fathers.
What Is the Average IQ of Someone With Down Syndrome
Down Syndrome is a common birth defect that is known as the most frequent form of intellectual disabilities.
Research shows that almost one in every 700 newborns has Down Syndrome, which shows that it’s a common issue that needs to be taken seriously because this syndrome is the reason for a third of intellectual disability cases.
As you may know, normal people have low, normal, and high levels of IQ based on their test results; people with Down Syndrome can also take IQ tests to determine their IQs.
The average IQ of individuals with Down Syndrome is about 50, which is below the normal range of the IQ for a normal person. This number can vary between 30 and 70, which is still very low.
Based on these IQ levels, most of the developmental milestones in children with Down Syndrome are delayed. For example, they start to crawl around 8 to 22 months, while normal kids start crawling between 6 and 12 months.
Ultimately, the average IQ of most people with DS is about 50-69; some have moderate levels of IQ, which is 35-50, and in some cases, they score between 20 and 35.
FAQs
1- Can people with Down Syndrome have a high IQ?
As mentioned, most of the people with Down Syndrome have an average IQ between 50 and 70; however, an IQ score of 120 has been found in some cases, which is very rare.
2- Does Down Syndrome mean low IQ?
People with Down syndrome usually have mid to moderate IQ levels, which is below the range of the IQ level of a normal person.
3- What is the average IQ of a normal person?
The IQ score is defined with a median and mean of 100, and the average level of IQ in normal people is between 85 and 115.
Conclusion
Remember that Down Syndrome disorder is a lifelong condition that has no cure, but it can improve in some cases as there are services that help these people to improve their physical and intellectual abilities.
As mentioned in this article, people with Down Syndrome have an average IQ between 30 and 70, which affects their mental abilities, but it doesn’t mean all of them have difficulties in making relationships with normal people.
Note that these individuals are humans who are kind and respectful, just like any other people, who deserve to be treated well.
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