The following are summaries of the talks from the 1998 Cri du Chat conference, held in Warrington, England. The information comes from notes I made at the conference and I apologise if I have misunderstood anything and got it wrong!

 

Joan Overhauser's talk about Cri du Chat syndrome

When given a diagnosis based on genetic testing that involves the deletion of part of a chromosome we are given a string of numbers e.g. 46,XY,del(5)(p15.1). Joan explained what this means:
46 = the total number of chromosomes
XY = the sex of the person ( in this case male, XX = female)
del = deletion ( a piece missing)
(5) = which chromosome is affected( in this case the fifth largest)
(p15.1) = where the breakpoint is i.e.:
              p = the short arm (q would be the long arm)
              15.1 = the location. On chromosome 5 the specific bands are 11 (being the biggest deletion), 12, 13, 14, 15.1,  15.2,
              15.3 (being just the tip)
Why do breaks occur?
Most importantly, there is no reason! It isn't the fault of either parent!
10 -15% of all eggs and sperm have some kind of chromosomal abnormality, and all chromosomes can get deletions, but those with deletions on chromosome 5 seem to survive better than those with deletions elsewhere.
50% of all pregnancies result in a miscarriage, often due to a chromosomal abnormality or a more basic unknown reason. The body seems to know when a foetus is not developing properly and aborts it. It is infact amazing how many of us were born normal!
What does this loss mean?
Loss of genetic material on the short arm of chromosome 5 shows these typical features - babies and children tend to be small, tend to grow slowly, and have some kind of learning disability. They also have a strange high- pitched cry as babies, which often sounds like a cat - hence the name (Cat Cry). Cri du chat children may also have other disorders (though not all do) e.g. heart defects, seizures, reflux. If there are no major defects or immunity problems, that person's life span is expected to be normal.
Does the size of the deletion relate to the severity of the condition?
There are conflicting reports about this, but according to Joan's research the answer is no. Don't forget there are another 45 chromosomes also involved with brain development! However, if the person only has the very tip missing they seem to be completely normal, and if they only have a deletion at 15.3 their symptoms are pretty mild. The crucial building block for Cri du Chat syndrome seems to be somewhere in 15.2
Why is it important to do research?
Research helps us to get a more accurate description of the features of Cri du Chat syndrome, so that babies can be diagnosed as early a possible (so that early intervention problems can be started quickly). A more accurate prognosis may be given to the parents. Growth and development charts can be drawn up specifically for Cri du Chat children so that they can be compared with like. Specific genes and proteins can be identified and their function determined, which will hopefully help to develop therapies some time in the future.
 

Kim Cornish's talk about self-injurous behaviour

Kim has studied children from 66 families so far and is planning to undertake more research in the future (subject to funding).
She looked at self-injurous behaviour, aggressive/destructive behaviour against people or objects and stereotypic behaviour which was not goal directed.
She found the following behaviours occurred:
Behaviour                                                %
Self biting                                                  47
Pulling own hair                                         34.8
Scratching self                                           40.9
Vomiting/regurgitating                                57.6
Hitting head or body                                  54

Hitting others                                             65.2
Pulling other's hair                                      65.2
Scratching others                                       36.4
Pinching others                                           45.5

Destructive behaviour                                40.9
Rocking                                                    71.2
Twirling/twisting and object                        40.9
Repetitive vocalisations                             39.4

This is only part of the list, and Kim was keen to find out if behaviours increased with age, decreased with age or remained the same. She found that none increased with age though some remained pretty constant. However the following ones decreased with age: hitting own head, biting others, pulling other's hair, scratching others, vomiting.
A new collaborative study is to be done in the future which will correlate the genetics, behaviour, cognitive development (intelligence) and language acquisition.

 

Margaret Collins's talk about TNI (targeted nutritional intervention)

 Margaret has been  looking at TNI in Cri du chat Syndrome, Downs syndrome and the autistic spectrum. Her own son has Downs syndrome. The aim of TNI is to correct or ameliorate metabolic anomalies due to the over expression of genes or abnormalities in gene products. Before intervention can begin though, there is a need for assessment:
Anthropometric assessment (weighing and measuring)
Dietary assessment
Behavioural assessment
Behavioural assessment
Laboratory assessment

In the 1970's and 1980's it was hoped that big doses of vitamins and minerals would boost intelligence in Downs syndrome, but studies showed this not to be true, the control (placebo) group improved too! Also there were concerns about side effects, just because a little of something is good for you, it doesn't mean that alot of it will be also. TNI is widely used amongst Downs families, as many parents report improvements, but there is no scientific evidence and further research is needed, so clinicians do not recommend it's use. even less research has been done on Cri du Chat children. Research is therefor being proposed which will link genetic, psychological and nutritional information, which may provide a rationale for nutritional or other treatment interventions. the purpose of Targeted Nutritional Intervention is to prevent damage and maintain health in an individual.