How Common is Down Syndrome?
When it comes to defining as to how common is Down Syndrome, then in the United States the numbers are quite high than normal. In the United States itself, one out of every 800 child is born with Down Syndrome and about 5500 children are born each year with Down Syndrome. Coming to the number of people actually having this condition then the numbers are quite staggering and amounts to approximately 200,000 people in the United States alone. This is more so due to the fact that older aged females try getting pregnant thus having a baby with this condition, although females of any age can have a baby with Down Syndrome.
Can Down Syndrome be Inherited?
Majority of the cases of Down Syndrome are not inherited meaning that this is a genetic condition but it is not necessary that it may run in families. A female with Down Syndrome, or a history of someone in her family or her husband's family with Down Syndrome does not necessarily mean that they will have children with this condition as well. When Down Syndrome is caused due to Trisomy 21 then the abnormality or cell dysfunction occurs during the formation of reproductive cells in the parent.
Normally, this occurs in the egg cells but at times it may also occur in the sperm cells as well. This cell dysfunction leads to the cells having an extra copy of chromosome 21 in the cell leading to Down Syndrome. If the child gets the extra copy of the gene during genetic formation of the child then that child will end up having Down Syndrome. Individuals with translocation type of Down Syndrome may inherit the condition from the parent who may not necessarily be affected from Down Syndrome.
The genetic arrangement between chromosome 21 and other chromosome in the parent remains balanced and is called translocation and results in no health concerns but when these cells are passed on to the offspring there may be imbalance of the cells leading to the child having an extra copy of the chromosome 21 causing Down Syndrome.
Another type of Down Syndrome called the Mosaic Type Down Syndrome is also a condition which cannot be inherited. Mosaic Down syndrome is not inherited and the abnormality of the cells occur as a random event during fetal development leading to the infant having Down Syndrome.