By MIRRIAM ZIMBA –

THE Down Syndrome Foundation of Zambia (DSFZ) has described Down Syndrome as one of the most common human genetic birth defects.

Speaking in a interview with Times Health, the foundation’s chairperson Kifita Kimbonyi said the condition is a chromosomal disorder that includes a combination of birth defects and intellectual disabilities as well as characteristic physical features.

Mr Kifita said most of these symptoms can be effectively managed is early medical intervention is sought and adhered to.

Mr Kimbonyi, who described Down Syndrome as a medical condition rather than an illness said the severity of the problems varies greatly among infected individuals.

He outlined the two major causes of Down Syndrome as namely mosaicism and translocation.

“Down syndrome is caused by extra genetic materials from chromosome 21. An individual inherits one chromosome per pair from the mother’s egg and one from the father’s sperm. When an egg and a sperm join together, they normally form a fertilized egg with 46 chromosomes,” he said.

He noted that in the event that something goes wrong in the process of fertilization, leading to either the sperm or egg dividing incorrectly, sometimes causing an egg or sperm cell to have an extra chromosome number 21.

He said when this cell joins with a normal egg or sperm cell, the resulting embryo has 47 chromosomes instead of 46.

Mr Kimbony said Down syndrome is called trisomy 21 because affected individuals have three number 21 chromosomes, instead of two, adding that this type of error in cell division causes about 95 percent of the cases of Down syndrome.

Occasionally, before fertilization, a part of chromosome 21 breaks off during cell division and becomes attached to another chromosome in the egg or sperm cell.

The resulting embryo may have what is called Translocation Down Syndrome., meaning that affected individuals have two normal copies of chromosome 21, plus extra chromosome 21 materials attached to another chromosome. This type of error in cell division causes about 3 to 4 per cent of cases of Down syndrome.

In some cases the parent has a rearrangement of chromosome 21, called a balanced translocation, which does not affect his or her health. On the other hand 1 to 2 percent of individuals with Down syndrome have form called mosaicism, in this form; an error in cell division occurs after fertilization.

Affected individuals have some cells with an extra chromosome 21 and others with the normal number.

He advised parents and guardians with children who have such conditions to ensure that they seek medical intervention on the management of the condition.

Mr Kimbonyi said there are so many headways and successful scientific findings and therapies that are available today that are helping to improve the quality of life for our children.