BMJ Learning

Down's syndrome in children and adults

د. حسين محمد جمعة
اختصاصي الامراض الباطنة
البورد العربي
كلية طب الموصل
2010

If we had a situation where pregnancies with a fetus with Down's

syndrome were not terminated, we'd expect the live birth rate of
children with Down's syndrome to be about 1 in every 600 live births.

The risk goes up as the mother's age goes up. By the time you're

over 40 your risk is at least 1 in 100 and it goes up more steeply
than that as you progress through your 40s. When you're down in
your early 20s the risk is much lower, it's probably around about 1 in every 2000.

Down's syndrome is a chromosomal disorder, which is in most cases due to a whole extra chromosome 21, so it's Trisomy 21
although in a smaller number of cases there are translocations. So,the normal number of chromosomes but with some added material
from 21.
There are also some Down's yndrome mosaics, where only some of the cells in the body have got the extra chromosome.


Probably one of the commonest things to be aware of is that about
50% of babies born with Down's syndrome also have congenital heart disease.
Other common problems are hearing problems,particularly glue ear and visual problems, refractive errors are very
common in people with Down's syndrome, so it's important to pick up on those.

Over and above that, there's an over representation of all autoimmune disorders in people with Down's syndrome, so there's
an increased incidence of people with coeliac disease, diabetes, rheumatoid arthritis. Also, children with Down's syndrome in particular are at increased risk of leukaemia.

the absolute diagnostic test is an

amniocentesis or chorionic villus sample; both of which are invasive in which to carry some risk of fetal loss. So, that's something that women have to be aware of and which can be quite difficult.
There are a whole range of screening tests available and many of these are offered more or less routinely.

Most babies that are born are diagnosed around the time of birth but at the six week check the things that will probably be apparent, will be the characteristic facial appearance, with the
slant to the eyes, the relatively
flat nose, a
flat back of the head, a
flat occiput.

Also, generally quite a characteristically low muscle tone; so when you take the baby up he or she seems to slip through your fingers.
Then there are other subtle signs like there is often a wide gap between the first and second toes, there's often some little things called Brushfield spots in the eyes if you look for them.


You can't escape the fact that children with Down's syndrome are universally going to have some degree of learning delay although
again, the IQ range is quite wide. One can't predict a child's exact level of functioning. In terms of behaviour, there's a behavioural
stereotype which is often quoted about children with Down's syndrome being
friendly, loving, and fond of music.

Most people with Down's syndrome will fall into the moderate

learning disability range, rather than the severe learning disability.

Hypothyroidism, there's arecommendation

in most countries now, that people should actually have their thyroid function checked
regularly by blood testing because clinically it is just a very difficult diagnosis to make in this group of people, where the symptoms can get missed.

The other ones that are recommended, are hearing and vision testing.

Coeliac disease
There is a school of thought emerging that we should be moving to regular screening

The life expectancy of people with Down's syndrome has increased dramatically. In the 1960s the life expectancy of a baby born with Down's syndrome was only about 18 years but it's now moved to around about 60.

there does seem to be a link between Down's syndrome and dementia but this is something which is really difficult to unravel.