Clue to early pre-eclampsia test

Pre-eclampsia can affect one in ten pregnancies

Researchers have discovered a gene which may be linked with pre-eclampsia in some women - raising hopes of a diagnostic test and early treatment.

Mice, genetically-engineered to be deficient in an enzyme called COMT, were found to develop pre-eclampsia.

Writing in Nature, the US researchers said low levels of COMT are also seen in pregnant women with the condition - which is dangerous for mother and baby.

But obstetric experts said a test would still be a long way off.

Pre-eclampsia accounts for 15% of all premature deliveries in the UK.

This is because the only way to completely cure pre-eclampsia is to deliver the baby. Left untreated, the condition can lead to convulsions, kidney failure, serious liver problems and death.

The researchers from Harvard Medical School looked at proteins which may be involved in pre-eclampsia by affecting the level of oxygen delivered to the placenta.

If this is a gene responsible for pre-eclampsia in some families then it would be a nice genetic test Dr Raghu Kalluri, study leader

They settled on COMT (catechol-O-methyltransferase), an enzyme involved in the development of new blood vessels and a compound it produces called 2-methoxyoestradiol (2-ME).

Mice without any COMT also failed to produce 2-ME, which normally increases during the last three months of human pregnancy.

They found when mice were given back the COMT it cured their pre-eclampsia. The researchers say this has important implications for a potential treatment.

Measurement

As well as the potential for a genetic test to identify women at risk, it is possible to measure 2-ME in blood or urine, which could identify those who need more close monitoring, they added.

"If this is a gene responsible for pre-eclampsia in some families then it would be a nice genetic test," said study leader Dr Raghu Kalluri.

"But also levels of 2-ME can be measured in pregnant women and they can be supplemented with a pill.

"We would be giving back what is missing in the mothers and babies."

The team are now planning a large clinical trial in women to look at the effect of COMT.

Professor Andrew Shennan, consultant obstetrician at St Thomas' Hospital in London said currently all women are closely monitored for signs of pre-eclampsia.

"If you had a very good test which said 'you don't have to see this woman but you need to monitor this woman' it would be very useful."

But he stressed other markers had been found in the past and turned out not to be useful.

Professor James Walker, spokesperson for the Royal College of Obstetricians and Gynaecologists agreed it was a potentially interesting new area of research.

"There's a lot of big studies at the moment looking at this area but the problem is that screening is very expensive for the small percentage who have the disease."