Down's syndrome
Every human cell holds forty-six chromosomes. In Down's syndrome chromosome twenty-one comes in three copies instead of two, and that extra genetic material…
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Every human cell holds forty-six chromosomes. In Down's syndrome chromosome twenty-one comes in three copies instead of two, and that extra genetic material changes the way a child grows and learns. Nothing a mother did or failed to do before or during pregnancy causes it: the error happens as the egg or sperm matures, or in the first days after conception, long before anyone knows a pregnancy has begun.
Where the extra chromosome comes from
In about ninety-five cases in a hundred the spare chromosome arrives by chance: as the egg or sperm divided, one pair failed to separate. Nobody passes this form on.
Two rarer forms exist. In the mosaic form the extra chromosome sits in only some cells, and the effects tend to be milder. In the translocation form a piece of chromosome twenty-one attaches to another chromosome, and this is the one situation where the condition genuinely can run in a family: a parent may carry a balanced rearrangement without any signs of it. That is why families are offered a test to establish which form it is, and why parents are examined when it proves to be a translocation. For any later pregnancy this matters a great deal.
The chance rises clearly with the mother's age, but people often draw the wrong conclusion from that. Most babies with Down's syndrome are born to women under thirty-five, simply because far more babies are born at that age. Age shifts the odds; it does not sort women into those this concerns and everybody else.
What is offered during pregnancy
Late in the first trimester, while the fluid at the back of the baby's neck can still be measured, a combined screening test is done: an ultrasound scan alongside a blood test measuring two pregnancy proteins. Put together with the mother's age, these give a probability, not a diagnosis. There is also a test of cell-free fetal DNA in the mother's blood, which is more accurate but is still screening rather than an answer.
Only an examination of the baby's own chromosomes settles it: chorionic villus sampling late in the first trimester, or amniocentesis from the second. Both carry a small risk of losing the pregnancy, and that has to be explained beforehand rather than afterwards.
Whether to have screening at all is the woman's decision, and declining spoils nothing in the care that follows. It helps to think in advance what the result is for: preparing, arranging to give birth where there is paediatric cardiology, or deciding otherwise. Every family answers that differently, and genetic counselling exists to explain the numbers without pressure, not to supply the answer.
The first few weeks
A newborn with Down's syndrome is first of all a newborn: feeding, sleeping, crying and wanting to be held. What is noticeable is something else. Low muscle tone makes feeding hard work, and the baby tires and falls asleep at the breast without having taken enough. Feeding support, more frequent feeds and sometimes expressing milk solve it.
During these weeks the things that must not be missed are checked: the heart, hearing, thyroid function and whether the bowel is open. Some problems show at once, others only on an echocardiogram, which is why every baby has one even when they seem perfectly settled.
Parents are told a great deal at once in these weeks, and almost none of it stays. Write your questions down and come back with them; nobody expects it all to sink in first time.
Development, speech and school
Children go through the same stages as everyone else, at their own pace, and the spread of ability is very wide: one adult lives independently and works, another needs help every day. No one can predict which in advance. What genuinely helps:
- speech and language therapy, starting not when it is time to talk but earlier, with chewing, swallowing and sounds;
- physiotherapy where tone is low, so that sitting, standing and walking come sooner;
- occupational therapy: dressing, holding a spoon, doing up a button;
- showing rather than only explaining, because what is seen is taken in more easily;
- a predictable daily routine, which lowers anxiety and frees up energy for learning;
- regular hearing and sight checks, since undetected hearing loss looks exactly like delayed speech.
The main rule for the adults nearby is to talk to the person rather than over them. Even with a parent standing there, the question goes to whoever it is about, and the tone is chosen to match their age, not the way they answer.
Most children go to ordinary schools with support, some to specialist ones. There is no right answer for everyone: it depends on how much help this particular child needs and what exists nearby.
Health that is watched more closely
Down's syndrome raises the likelihood of several conditions. None is inevitable, but each is better caught early.
- Heart. Around half are born with a congenital heart defect. Some close on their own, others need surgery in the first year.
- Ears and hearing. Fluid collecting behind the eardrum is very common. Hearing drops unnoticed and hits speech hardest.
- Sight. Squint, short and long sight, congenital cataract.
- Thyroid. An underactive thyroid can appear at any age, and the sluggishness it brings is easily put down to the syndrome itself. That is why the blood test is repeated regularly.
- Breathing in sleep. Obstructive sleep apnoea is common. Snoring with pauses, daytime sleepiness and poor concentration are reasons to investigate.
- Bowel. Constipation and coeliac disease; in newborns, an obstruction needing urgent surgery.
- Infections. Defences are weaker, and pneumonia or flu run a harder course. Routine vaccinations matter particularly here.
- Blood. Some newborns have a temporary disturbance of blood cell production which settles by itself but needs watching. The risk of childhood leukaemia is higher than usual.
- Neck vertebrae. In some people the first and second bones of the neck are held together more loosely than normal. In itself this shows nothing, but an injury or a sharp movement can compress the spinal cord.
Adults are given a planned check-up once a year even when nothing is wrong. From around the age of thirty, memory is watched separately: Alzheimer-type changes appear earlier here than on average, because the key gene sits on chromosome twenty-one itself. Regular checks give something to compare against when a question arises.
When waiting is not an option
Call an ambulance straight away (across European countries the single number 112 works) if:
- a child turns blue, becomes floppy, breathes fast and hard, or stops feeding;
- a newborn vomits greenish fluid, has a swollen tummy and is not passing stools;
- weakness appears in the arms or legs, the way of walking changes, things drop out of the hands, the head is held to one side, or the neck hurts, especially after a fall or a knock: this is how pressure on the spinal cord shows itself;
- control of the bladder or bowel is suddenly lost;
- sudden pallor, widespread bruising or bleeding gums appear.
See a doctor within days if a child has stopped doing something they could already do; if behaviour or mood has changed sharply; if snoring with pauses in breathing has started; or if someone tires faster, gains weight and feels the cold. People with Down's syndrome often cannot describe what hurts and where, so a change in behaviour is the complaint, and it deserves to be taken as seriously as words.
Adult life
An adult with Down's syndrome has the same rights and the same wishes as anyone else: to work, to handle their own money, to choose where and with whom they live, to have friends, to play sport. How much help is needed varies enormously, from almost none to daily support with ordinary tasks.
Work brings more than income; it brings shape to the day and a circle of people, and many countries run supported employment schemes. Housing likewise takes different forms: the family home, a place of one's own with a support worker calling in, or shared living with support. The choice belongs to the person, and those around them should lay out the options in plain language rather than decide for them.
Movement deserves a separate word. It keeps weight in check, supports the heart and muscles, and in a group settles the question of company along the way. One restriction: where the neck is known to be loose-jointed, forward rolls, diving head first and contact sports are avoided. Ask the doctor before signing up, not after.
For family and those close by
The first weeks after a diagnosis are often hard, and that is normal. Much of the fear is not about the child but about the pictures of the future that imagination supplies and that almost never come true. A simple rule helps: do not look too far ahead. Nobody can say what a child's life will be like, with Down's syndrome or without it.
Talking to families who have been through the same thing is worth more than any leaflet: they know what to ask doctors, how support is organised in your country, and which fears turned out to be groundless. Ask a paediatrician or the local social services about the nearest group. And remember that the person doing the caring also needs rest and sleep: asking for help is not weakness but the condition for lasting.
Online consultation
Remotely it is easy to deal with anything that needs no examination: what a screening result means and how a probability differs from a diagnosis; which routine checks are due by age and which have gone undone for a while; how to read a thyroid blood test; when to see a speech therapist; whether snoring, listlessness or changed behaviour is worth worrying about and who to see about it. The signs on the emergency list are not assessed remotely: for those you call an ambulance.
This material is for information only and does not replace medical advice.
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Discuss your symptoms and possible next steps for Down's syndrome with a doctor online.
