Thirty years ago, more than 60 per cent of babies born with Down syndrome died before they were 10 years old. Now, 90 per cent of such children reach the age of 10 and many of them go on to live well into their 50s. There is one person with Down syndrome living in the west of Ireland who is 73. Early surgical intervention to correct congenital heart defects is the biggest factor influencing survival. Early diagnosis of thyroid malfunction, hearing disorders and sight problems has also helped improve the quality of life of many children with Down syndrome.
In the Republic, one baby in every 550 to 650 is born with Down syndrome. This figure has remained static over the last number of years, according to Down Syndrome Ireland. This compares to an incidence of one baby in every 800 to 1,000 in other developed countries. Down syndrome is caused by the presence of an extra chromosome 21, bringing the total of chromosomes to 47 instead of 46. Chromosome abnormalities account for 0.6 per cent of all birth defects, according to UK figures.