What is Cri-Du-Chat Syndrome? (CDC)
CDC is a chromosomal abnormality which results in learning difficulties. Most children will have severe learning difficulties, though some are only mildly affected. It is estimated that CDC affects 1:50 000 people world-wide. It was discovered by Dr Lejeune in France in 1963, and he gave the syndrome the name "cat cry" due to the characteristic cry of newborns which is not unlike the mewing of a kitten.
click here to see pictures of human
All of us have 46 chromosomes in our cells, 23 from our mother, 23 from our father. Errors can occur when cells are dividing and chromosomes can break, and/or attach in the wrong place. These errors are extremely common - they are a normal part of nature which allows a species to change and evolve. Most miscarriages are caused by a chromosomal error which is not compatible with life. CDC is caused by genetic material being lost from the short arm of the 5th (5th largest) chromosome. It is not the fault of either parent, and most cases come out of the blue, only about 20% of cases are inherited due to a balanced translocation (material from one chromosome has become attached to another) in the chromosomes of one of the parents. People with balanced translocations are perfectly normal as no genetic material is lost, so they probably will not know that they are carriers until they have an affected child, unless there is a history of the CDC in the family.
click here to see pictures of human chromosomes
Please note that not all people with CDC will show all of these features.
Characteristic high pitched cry at birth
Low birth weight
Poor muscle tone
Round "moon" face
Small thin build and short stature
Typical facial features - small chin, long nose, which don't look particularly odd, but the children look as if they are related. Look at the pictures
Delay in mobility, speech and toilet training
Older children often have protruding teeth as their heads and jaws are small, but the teeth are normal size.
Some children also have internal abnormalities such as heart defects or absent kidneys, some also develop curvature of the spine.
Contrary to what the old textbooks say CDC children do not die in early infancy. Life span is expected to be relatively normal, though there are some signs of premature ageing.
Children with CDC all have some degree of learning difficulty, from mild to severe. This affects every part of their lives so that it takes longer to learn to do everything, couple this with poor muscle tone, and some things become very difficult. However they do go on learning and improving throughout life.
Many babies have feeding difficulties such as a poor suck, or reflux problems. Some take so little food by mouth that they have to have gastric tubes. Older children may have difficulty in chewing, so all food will need to be prepared to a certain consistency.
Speech is delayed, and for many children with CDC if is very delayed, some will never be able to speak. However they do have good understanding of language, and will communicate, either in their own way or by using sign language or picture boards.
Walking is also delayed, though most will learn to walk eventually. CDC children often have an awkward gait and appear clumsy.
CDC children will have difficulty in toilet training, though most do learn to control their bowels and bladders. A few will still need incontinence pads at night into adulthood. Many people with CDC are constipated.
Fine motor skills are also delayed, though some children will learn to write.
Most adults will be able to manage their personal care with minimal supervision.
Many babies and children with CDC have a disturbed sleep pattern, but this does improve with age.
Only a few have visual or hearing problems, but many have a hypersensitivity to noise, showing this as fear of particular sounds. These maybe loud or sudden noises or particular frequencies.
Many children with CDC have behavioural problems. They may be hyperactive, head bang or rock, or bite or pick their skin. Some develop obsessions with certain objects. Many have a fascination for hair and can't resist pulling it.
Drooling is a common problem, some children grow out of it, but if they don't there is a very successful operation to control it.
It is very difficult to predict how a particular child will develop, it doesn't seem to be related to the amount of genetic material which is lost. All parents can do is wait and see.
The chromosomal abnormality cannot be cured at the moment (but who knows in 100 years?), so treatment can only revolve around helping our children to develop as much as possible. Early and ongoing intervention is necessary from Speech Therapists, Physiotherapists and Occupational Therapists. It depends where you live what else you can get, but there are special nurseries, or home intervention programmes in most areas.
Children with CDC will probably need a lot of equipment, depending on their age. They may need special seating, cutlery and bowls for feeding; a buggy to get out and about in; a potty chair or adaptations to the toilet; a standing or walking frame; adaptations to the bed, or bedroom to keep them safe at night.
For some children drugs have been used with success to control behavioural or sleep problems.
The vast majority of children will attend a special school, though a few will cope in mainstream with support.
Many families use respite care for their children, this provides a social life for the child, and a break for the rest of the family and a chance to do things unsuitable for that child.
Ante natal testing
There are two tests which can be done before the baby is born to determine whether it has CDC.
Amniocentesis can be done around 18 weeks, which involves taking some amniotic fluid, and looking at the chromosomes of the baby in cells which have fallen from it's skin. This carries a risk to the baby of miscarriage of 1:100
Chorionic Villius Sampling (CVS) can be done several weeks earlier, and involves taking a tiny piece of the placenta and looking at the chromosomes. This has a higher risk to the baby of 2:100. It is likely that in neither test CDC would be spotted, unless they were specifically looking for it, as routine tests would be looking primarily for Down's syndrome.
In some countries it is now possible for couples who are carriers to have IVF treatment ensuring that only healthy embryos are implanted back into the mother.
This all sounds pretty bad and depressing, as I have been concentrating on the difficulties that children with CDC encounter. However these children are happy and healthy, loving and sociable. They love life and they show it. Bringing up CDC children brings its own rewards!
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