Question

What are the three types of down syndrome?

Answer 1

Down syndrome:

1. It is a congenital disorder that is present since birth.
2. This leads to an abnormal child with mental retardation, congenital heart diseases, facial deformity and also a reduced lifespan.
3. On the basis of the event that caused the trisomy, down syndrome can be said to have three types:

• Trisomy 21:

1. This is the most common type and also the most commonly found type of down syndrome.
2. In this type of down syndrome there occurs a trisomy of chromosome number 21.
3. Due to this the child has a total of 47 chromosomes instead of having 46 chromosomes.
4. Since the sex chromosomes are not affected that is why gender of the child is not affected by this disorder.

• Mosaic down syndrome:

1. This type is very rare.
2. In this type of down syndrome some of the cells are normal with 46 chromosomes and on the other hand some of the cells are abnormal with 47 chromosomes.

• Translocation down syndrome:

1. In this type of down syndrome the trisomy of 21st chromosome is not complete.
2. The extra chromosome instead of remaining with the 21st chromosome itself goes and attaches to a different chromosome.
3. The chromosome to which this extra pair gets attached becomes abnormal.
4. In these types of patients the number of chromosomes is 46 only but one of the chromosomes is abnormal.