Down’s syndrome is a genetic disorder that was named after John Langdon Down, the doctor who first recognised it as a distinct condition in 1866.
Down’s syndrome affects a baby's normal physical development and causes moderate to severe learning difficulties. It is a lifelong condition that develops when a baby is still in the womb (uterus).
Children who are born with Down’s syndrome also have a higher chance of developing other conditions, some of which are life-threatening. For example:
- congenital heart disease – a general term that describes a series of birth defects that affect the heart
- sight and hearing problems
- Alzheimer’s disease – a common form of dementia (a deterioration of mental abilities, such as memory and reasoning) that often affects people who are over 65 years of age
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.
Screening
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.
See Down’s syndrome - diagnosis for more information about screening.
Outlook
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.
