Gene Variation Could Cause Preeclampsia

Faulty genetics may play a role in whether or not a pregnant woman develops preeclampsia and could explain why the condition runs in families, according to a report in Nature Genetics.

Preeclampsia is a potentially life-threatening condition marked by three specific symptoms: water retention (with swelling particularly in the feet, legs, and hands); high blood pressure; and protein in the urine, a sign of possible kidney damage. All three symptoms must be present at the same time.The condition affects 2 to 7 percent of pregnancies. Its cause is poorly understood, but genetic susceptibility has often been raised as possibility.

Using gene sequencing techniques, researcher Cees Oudejans and colleagues analyzed families with two or more sisters affected by preeclampsia among women in the Netherlands.

The condition is not inherited yet can affect various members within a family.

Analyzing placental tissue, which is believed to be the source of symptoms of preeclampsia, researchers discovered that most women with preeclampsia carry an ill-functioning variation of a particular gene. An identical ill-functioning gene was found between affected sisters. The researchers also show that the gene appears to be inherited along maternal lines.

The gene -- STOX 1 -- works in the placenta, the lining of the uterus. The researchers say that loss of function of this gene may lead to many of the complications seen in preeclampsia, such as liver abnormalities, anemia, and blood clotting problems.

Preeclampsia is typically diagnosed in pregnant women past 20 weeks of pregnancy who have persistent high blood pressure (> 140/90 mm Hg or higher). These women also have high levels of protein in the urine.

By Kelli Miller, reviewed by Brunilda Nazario, MD

SOURCES: van Dijk, M. Nature Genetics, April 2005; vol 37: pp 1-5.