Downs Syndrome FAQ

What is it?

Down’s syndrome is a chromosomal irregularity. Cells in the human body usually have 46 chromosomes present. However, in 1959, French physician, Jerome Lejeune, observed that the cells of people with Down’s syndrome had 47 chromosomes present in each cell.

An English doctor, John Langdon Down, was the first to publish a description of the condition in 1866; the syndrome was subsequently named after him.

How is it caused?

It is unknown what causes the presence of the additional chromosome. It happens throughout the world and is not specific to any one race, age or social class. It can happen to anyone.

How common is Down’s syndrome?

Down’s syndrome is uncommon in the UK. For example, from 2007 to 2008, 1,843 cases of Down’s syndrome were diagnosed during pregnancy, and 743 babies were born with the condition. This means that about 1 in every 1,000 live births is affected by Down’s syndrome.

Down’s syndrome affects all ethnic groups equally. Boys are slightly more likely (around 15%) to be born with Down’s syndrome than girls.

The cause or causes of Down’s syndrome are unclear, but the single biggest risk factor for the condition seems to be the age at which a woman gives birth. The older a woman is when she has a baby, the higher the risk of her baby having Down’s syndrome. The greatest risk (1 in 30) is associated with women who are 45 years of age or over.


Routine screening for Down’s syndrome is carried out during pregnancy in order to identify women who are at high risk of giving birth to a child with Down’s syndrome.

If screening proves positive (confirms that the baby has Down’s syndrome), counselling is available to provide support and information, so that the woman and her partner can make an informed decision about whether to proceed with the pregnancy.


The outlook for Down’s syndrome can vary widely, depending on whether a child with the condition also develops any other serious health conditions.

Children with Down’s syndrome are most vulnerable during the first year of their life. About 15% of children with Down’s syndrome will die during the first year, usually from a complication that arises from congenital heart disease.

After the first year of life, the outlook for children with Down’s syndrome improves dramatically. Due to advances in treatment, the average life expectancy for a person with Down’s syndrome is around 50, and this may well improve in the future.

Every child’s personality is different, and it is important never to stereotype a person with Down’s syndrome. However, in general terms, people with Down’s syndrome tend to have warm, gentle and cheerful personalities, despite the day-to-day problems they have to face.

The above information is provided courtesy of NHS. (c) Copyright NHS 2012. All rights reserved.

Further Information on Down’s syndrome

Please visit our Links page for a list of websites containing more information on Down’s syndrome.