Genetic Mutations Linked to Preeclampsia

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An international team of scientists has discovered genetic mutations in some women who developed preeclampsia, a potentially life-threatening condition whose exact cause is not known. Preeclampsia occurs in about 10 percent of pregnant women and accounts for 15 percent of premature births.

New treatments for preeclampsia are needed

The new study, which was a collaboration among experts from Washington University, Weill Cornell Medical College, University of Utah at Salt Lake City, Newcastle University (UK), and Georges-Pompidou Hospital (Paris), involved 250 pregnant women who had the autoimmune diseases lupus and/or a related condition called antiphospholipid antibody syndrome, and 59 women with severe preeclampsia who were free of autoimmune disease.

During the study period, 30 of the 250 women developed preeclampsia, and 10 had had preeclampsia in the past. The researchers then looked for three genes associated with a potentially deadly disorder that triggers uncontrollable immune response (atypical hemolytic uremic syndrome) in the study participants. Among the 40 women with current or previous preeclampsia, seven (18%) had mutations in at least one gene. In 59 pregnant women with severe preeclampsia and no autoimmune disease, five (8%) had genetic mutations.

Preeclampsia begins early in pregnancy and occurs when there is a malfunction concerning the placenta, which delivers critical oxygen and nutrition to the fetus. The condition is not diagnosed, however, until after the 20th week of pregnancy, when affected women develop high blood pressure, proteinuria (protein in the urine), headache, and swelling of the face and hands.

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Currently the only treatment for preeclampsia is delivering the infant, although delivery before week 37 is not recommended unless it is too dangerous for the pregnancy to continue. If preeclampsia is not treated, it can lead to eclampsia, characterized by grand mal seizures and/or coma, as well as stroke, kidney and liver damage, and breathing problems.

A 2005 study from the Centers for Disease Control and Prevention reported an overall preeclampsia-eclampsia case-fatality rate of 6.4 per 10,000 cases at delivery. Black women are twice as likely to be affected as are white women.

According to John P. Atkinson, MD, of Washington University School of Medicine in St. Louis and senior author of the study, “Preeclampsia seems to involve multiple hits,” which may involve a “genetic predisposition for small blood vessels,” which in turn can be complicated by having an autoimmune disorder, a risk factor for preeclampsia. Pregnancy in such women can exert significant stress on a woman’s organs.

Currently, a drug to treat atypical hemolytic uremic syndrome, eculizumab, is in clinical trials. Atkinson noted that if additional research validates a link between immune system dysfunction and preeclampsia, eculizumab could be adapted to treat mothers at risk.

Two of the three genetic mutations explored in this study are, to the authors’ knowledge, the first genetic mutations found to be associated with preeclampsia in pregnant women who have lupus and/or antiphospholipid antibody syndrome. Research continues on any links between genetic mutations and preeclampsia.

SOURCES:
Salmon JE et al. PLoS Medicine 2011; 8(3): e1001013 doi: 10.1371/journal.pmed.1001013
Sibai BM. Obstetrics and Gynecology 2005 Feb; 105(2): 402-10

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