A protein made by the fetus may lead to preeclampsia in moms.

People born to mothers who had the prenatal disorder were more likely to have certain DNA variations near a gene known to influence blood vessels. The results, published online June 19 in Nature Genetics, point to that gene as a possible preeclampsia culprit, and may help scientists develop ways to stop or prevent the pregnancy complication. Preeclampsia, which is marked by a dangerous spike in blood pressure, affects about 5 percent of pregnancies and is estimated to kill over 70,000 women a year globally.
Scientists have known that preeclampsia can run in families, but the genetics of the fetus hadn’t been scrutinized. “Over the years, people have looked at mothers’ genes,” says geneticist Linda Morgan of the University of Nottingham in England. “This is the first large study to look at babies’ genes.”

Morgan and colleagues compared DNA variations in 2,658 babies, children and adults born to mothers who had preeclampsia with those in more than 300,000 people. (This large group probably included some people born to mothers with the condition, but the vast majority were not.)

A genome-wide association study (GWAS), a technique used to comb through DNA looking for genetic variations that may be linked to a disorder, pinpointed a spot on chromosome 13, near a gene called FLT1. That gene is involved with blood vessel formation, an intricate process for the placenta as it grows into the inside wall of the uterus and merges the baby’s blood supply to the mother’s. The same genetic hot spot turned up in tests of a second group of offspring from mothers who had preeclampsia, Morgan and colleagues report. Another DNA variation near the gene also showed a link to the disorder.

Identifying FLT1 “makes a lot of sense,” says Ananth Karumanchi, a vascular biologist at Beth Israel Deaconess Medical Center in Boston, who was not involved in the study. Earlier experiments by Karumanchi and others suggest that the gene plays a role in preeclampsia.

Preeclampsia is kicked off by the placenta, an organ grown mostly from fetal cells that helps provide nutrients to the fetus. And though the details are unclear, some scientists suspect that unhealthy placentas start to pump out too much Flt-1 protein. A version of the protein called sFlt-1 can then slip into a mother’s bloodstream, where it may damage blood vessels in a way that leads to high blood pressure.
The GWAS results can’t explain the bulk of preeclampsia cases. A fetus carrying a single copy of one of the troublesome variants near FLT1 raised a mother’s risk of preeclampsia by about 20 percent, the analysis suggests. Other risk factors are known to be much stronger, Morgan says, including previous high blood pressure, former preeclampsia diagnoses or carrying twins.

Karumanchi says that the genetic results might not be strong enough on their own to make the case that the gene is involved. But other work points to FLT1. “We feel it’s the right target,” he says.

In Europe, a preliminary clinical trial is testing a filtration method that removes excess sFlt-1 protein from the blood of women with signs of preeclampsia. So far, about 20 women have undergone the procedure, says nephrologist Ravi Thadhani of Massachusetts General Hospital in Boston. Early results are “quite encouraging,” he says, and he hopes to expand the study soon.

Across Europe, rivers aren’t flooding when they used to.

Long-term changes in temperature and precipitation are making some rivers flood days, weeks or even months earlier than they did 50 years ago, and pushing flooding in other areas much later, researchers report August 11 in Science. Those changes could impact people, wildlife and farms near rivers.

Previous studies have shown that climate change is likely to increase the severity and frequency of coastal floods, but it can be tricky to concretely link river flooding to climate change, says Günter Blöschl, a hydrologist at the Vienna University of Technology who led the study.
Coastal flooding is worsened largely by one overriding variable that can be tracked: sea level rise. But river flooding is affected by a complex set of factors, says Rob Moore, a policy analyst at the Natural Resources Defense Council in Chicago who specializes in water issues. Both the timing and quantity of precipitation matter, as does the type of soil and whether it’s dry or already waterlogged when rain hits. What’s more, changes in land use around a river or engineering projects such as dams that change river flow can also affect flood risk — but aren’t necessarily related to the climate.
So instead of tracking the size or frequency of river floods, the researchers examined the seasonal timing of those floods. That measurement is less impacted by factors that have nothing to do with climate. Blöschl worked with researchers from 38 countries to analyze hydrological data collected at 4,262 sites across Europe from 1960 to 2010.

Flood season shifted as much as 13 days earlier or nine days later per decade, the researchers found. Over the entire study period, that shift added up to floods in some regions occurring, in the most extreme cases, as much as 65 days earlier or 45 days later. The biggest changes were in Western Europe, where a quarter of the monitoring sites recorded flood timing shifts of more than 36 days over the 50-year period. Elsewhere, effects were more moderate, though still measurable: In northeastern Europe and the area around the North Sea, for instance, more than half of the stations showed shifts of more than 8 days.
The effect varies substantially by region because not all parts of Europe experience the same sorts of floods, says Blöschl. In southern Sweden and the Baltics, floods are mostly driven by snowmelt. Warmer local temperatures make the snow melt earlier in the spring, shifting flood season up, too. In southern England, on the other hand, heavy autumn rains saturate the soil, and subsequent winter deluges can cause flooding. Flood season there is driven by when the soil gets too waterlogged to take in more moisture.

The study shows that flood timing has changed, but does not address specific consequences. It’s clear, though, that off-season flooding could have far-reaching effects, especially if these trends continue. Animals that rely on river conditions at a certain time of year in order to breed or find food could be affected by surprise floods. Out-of-season floods or unexpected dry spells could damage crops.

Plus, people are less prepared when big floods happen off-season, says Moore. While a comprehensive study like this one hasn’t been done in the United States, floods are occurring at unusual times here, too, he notes. Moore cites devastating floods that swelled the upper Mississippi River to a record size in December 2015 — not the time of year when the river is expected to overflow its banks. That flooding, combined with tornadoes spurred by the same storm system, killed more than 50 people and caused almost $2 billion in damage.

Just a stab in the dark, but you’ve probably heard: There is a total solar eclipse today, August 21.

For the first time since 1979, the moon’s shadow will zip across the continental United States. The shadow will travel from Oregon to South Carolina in a swift 92 minutes. For those in the path of totality, total darkness will last only a couple of minutes. There and elsewhere in most of the United States, the moon will partially block the sun for around three hours.
If you don’t already have plans to travel to the 115-kilometer-or-so-wide path of totality, well, you’re probably too late. But here are some links to help you experience the eclipse, whether or not you’re able to see it in person.

The eclipse will be visible in all of North America — as well as in Central America and a small part of South America. Wondering what you’ll see where you live? Check out this interactive map from NASA or this cool tool from Vox.

Still need eclipse glasses? While many retailers have been sold out for days, some organizations are handing out free glasses at eclipse-watching events. Check your local TV/newspaper/radio stations’ newsfeeds for the latest. Make sure your glasses are safe.

No eclipse glasses? Never fear! You can still see the moon eclipsing the sun by making a pinhole projector or a box projector. Or just let sunlight shine through something that has holes, like a colander or Ritz Cracker (look at the ground to see the shape of the shadow the holes cast).

Watching with kids? Check out Growth Curve blogger Laura Sanders’ tips for protecting little ones’ eyes during the eclipse.
Which reminds me: Whatever you do, don’t look directly at the sun. Permanent damage to your eyes may result. If you’re in the path of totality, officials say it’s OK to look directly at the sun once the moon completely blocks it. But that’s very brief, so be prepared to quickly look away or shield your eyes once the moon slips out of total alignment.

Want to do more with your eclipse experience? It’s not too late to participate in a citizen science project.

Stuck indoors, or out of totality? Watch the livestream. NASA’s programming begins at noon Eastern on NASA TV, which you can watch at this link or right here:
Want some tunes to go along with it? The NASA interns made an eclipse playlist. There are also several Spotify playlists around, like this one from WXPN, this from the Washington Post and this one from the Boston Globe.

If all this excitement has you fancying a future in eclipse chasing, check out our interactive map of the next 15 total solar eclipses.

And let’s not forget that there will be a ton of science going on during the eclipse. Here are the big questions physicists and astronomers will seek to answer today.

Still want more? Follow us on Facebook and on Twitter for eclipse updates and RT’s of our correspondents in totality. Watch as the Science News team takes over the Society for Science & the Public’s Snapchat (Society4Science). And come back to Science News later today for a report from our astronomy writer, Lisa Grossman, who is spending the day in Casper, Wyo., with a research team that’s studying the sun’s wispy atmosphere, the corona.