Down syndrome

Down syndrome (DS) or Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21.[1] It is typically associated with physical growth delays, characteristic facial features, and mild to moderate intellectual disability.[2] The average IQ of a young adult with Down syndrome is 50, equivalent to the mental age of an 8- or 9-year-old child, but this varies widely.

Causes

Research shows that three types of chromosomal changes can lead to Down syndrome.

Complete trisomy 21. In this case, an error during the formation of the egg or the sperm results in either one having an extra chromosome. ...

Mosaic trisomy 21. Not every cell in the body is exactly the same.

Translocation trisomy 21.

Sign n symptoms

Common physical signs include:

Decreased muscle tone at birth.

Excess skin at the nape of the neck.

Flattened nose.

Separated joints between the bones of the skull (sutures)

Single crease in the palm of the hand.

Small ears.

Small mouth.

Upward slanting eyes.

Vaccination

Some children with DS may not mount the usual immune response to vaccines or natural infections. After a vaccine is given, the immune system produces antibodies that will fight off infections when a child is exposed in the future to that particular bacteria or virus. A significant number of people with DS do not produce enough antibodies after receiving the vaccines against pneumococcal or haemophilus influenza bacteria. A blood test can measure the antibody titer after the vaccines are completed at the one year checkup. If the response to the vaccines is insufficient, then it would be a good idea for the child to see an immunologist. Vaccines would probably be repeated and the child may need preventive treatments to avoid recurrent infections.