PAP smears as possible screening test for CF

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Pap smears reveal foetal problems

By Tom Noble

Health Editor

July 8 2003

Pap smears from pregnant women can reveal genetic defects in foetuses

and may replace invasive screening procedures such as amniocentesis

within two years, according to research revealed yesterday.

Scientists at the University of Queensland have developed a technique

that collects the foetal cells retrieved in a Pap smear, isolates

them from the mother's cells and tests them for conditions such as

Down syndrome and cystic fibrosis. The tests can also establish the

sex of the child.

Researcher Darryl Irwin said Pap smear tests were cheaper and safer

than invasive techniques, in which a thin needle is inserted into

amniotic fluid or tissue in the uterus, increasing the chance of

miscarriage by up to 1 per cent. Such tests are recommended for women

over 35, who have an increased risk of chromosomal abnormalities such

as Down syndrome. Almost 5000 n women had an invasive test in

2001.

Mr Irwin, whose research with Dr Ian Findlay of the Australian Genome

Research Facility was revealed at the International Genetics Congress

in Melbourne, hoped the Pap smear test would be widely available

within two years and be used to screen all women between eight and 12

weeks pregnant.

" Eighty per cent of Down syndrome babies are actually born to women

who are not screened because they are not at high risk. They are not

offered the test, " Mr Irwin said.

He said Pap smear tests should cost less than $100 and the results

were quick. Amniocentesis tests cost $400 and took days to return

results.

Mr Irwin said he had assigned all his intellectual property in the

discovery, and possible financial gain, to the university. " The other

benefit is that it is applicable to rural areas, which is really

applicable to Australia. Amniocentesis and chorionic villus sampling

can be done only in major capital cities.

" Someone in Charleville, for example, would have to fly to Brisbane

or Sydney to get those procedures done, whereas a GP can take a Pap

smear. It can be put in the mail, sent to a lab in one of those

cities and the result can be sent back the next day. "

If anyone showed positive results, an invasive test or ultrasound

should be used to confirm the finding, he said. " The other benefit is

we also do the cervical cancer screening at the same time. "

More than 600 pregnant women in Brisbane, five to 34 weeks pregnant,

had been tested in recent months, he said. About 1000 women would be

tested this year and results would be compared with their babies,

once born, to determine if the tests worked.

A key part of the initial research was to find the stage of pregnancy

that produced the clearest results.

Mr Irwin said that in 1971 foetal cells were discovered in the cervix

of pregnant women, but too few to do anything with. New methods found

0.3 per cent of cells were foetal, and a series of techniques have

allowed researchers to isolate material made up of an average 37 per

cent of foetal cells. By comparing a cell's DNA with the mother, the

foetal cells are isolated and analysed.

This story was found at:

http://www.theage.com.au/articles/2003/07/07/1057430137476.html

Leon