FOUR out of five children who are diagnosed with Down Syndrome are born to mothers who are in their early 30s or younger, according to a senior medical officer at the Child Development Centre (CDC).
In an interview with The Brunei Times, Dr Tan Silven said that evidence from worldwide research has shown that 80 per cent of babies who are afflicted with the condition are born to mothers who are less than 35 years old.
"Surprisingly, the average age of a mother of a baby with Down syndrome is 28," said Dr Tan Silven in the interview, which followed her talk entitled "Overview of Down Syndrome" during the Health Screening and Promotion Forum in conjunction with World Down Syndrome Day 2011.
Including this statistic in her talk, she said that the message here was to provide awareness to young mothers.
"When people say 'Oh you are a young mother your (child is) safe from Down Syndrome', that is not true,"she said.
"Just because you are less than 35, it does not mean that you are not going to have a baby with the condition."
She also said, however, that this could be accounted for by the fact that more babies are born to mothers under the age of 35.
"Even if there is a risk of one in a thousand, the number of babies born to the condition is still higher and this only reflects the fact that not many mothers have babies after 35," she said.
Asked whether this was the case in Brunei, she said that although there are no detailed statistics, 15 girls and 21 boys who have the genetic condition and registered at the centre are under five years old.
"From this statistic, most of the mothers are young mothers because I think in Brunei, we do not have a lot of older mothers,"she said.
She also said that babies born with the syndrome to young mothers may be slightly "different" from those born to older parents.
"This is known as Mosaic Down Syndrome which means that some cells contain Down's (Syndrome) and some don't," she said.
Children with this type of Down Syndrome, she said, tend to have less disabilities but not all the time.
On whether Down Syndrome was prevalent in Brunei, she said that the rate was similar to that of other countries.
"At the moment we have about six babies born every year with the syndrome which is about one in 1,000,"she said.
"The birth rate in Raja Isteri Pengiran Anak Saleha (Ripas) Hospital is about 6,000 a year, which is comparable to other countries, so the stats are about the same".
Other risks also include paternal age, she said, as there is now a possibility from world-wide research.
"The older father may also increase the risk as with any other chromosomal genetic disorder,"she said.
In most places,there has also been difficulty because mothers are only screened if they are over 35 years old.
She said that this was because the risk is higher for older mothers.
However, in Brunei specifically, screening is done in almost all mothers in the form of a blood test.
"But one of the things that Brunei does a little extra is that they do ultrasounds of all babies and this is good for detecting early problems,"she said.
Additionally, during her short lecture, she said that at present no one knows what causes the presence of the extra copy of chromosome 21, the root of the disorder.
"This can come from both the father or mother and no one is to blame and nothing done before or during the pregnancy causes the syndrome,"she said.
Also known as Trisomy 21, Down's Syndrome is a genetic disorder caused by the presence of all or part of an extra 21st chromosome.
It is named after John Langdon Down who described the syndrome in 1866.