What is Down's Syndrome

As it’s Awareness month I thought I would write about what Down’s Syndrome is and how it occurs.

Each cell in the body usually has 23 pairs of chromosomes i.e. 46 chromosomes in total per cell. One chromosome in each pair comes from the egg and one from the sperm. So when the egg and sperm cell meet they divide in half. But sometimes the egg or sperm cell keeps both copies of chromosome 21.

People with Down's Syndrome have one extra copy of chromosome 21 which is in every cell of the body. This is referred to as “Trisomy 21”.

This extra chromosome gives rise to a number of characteristics in the development of the body and the brain, and the presence of these varies for each child. For example about 50% of babies with Down’s Syndrome, but not all, are born with a congenital heart defect. This is the case for Coraline. I will write about some of the characteristics during this month.

It is named after the Victorian physician, John Langdon Down, who characterised the condition. The Langdon Down Centre, where he lived and worked, is half an hour’s drive from us and is now the Head Quarters of the Down’s Syndrome Association in the U.K.

Around one in every 1000 babies born in the U.K. has Down’s Syndrome.