Scientists just discovered a distressing new birth defect associated with Zika

We're still learning more about the ways the Zika virus affects babies whose mothers get infected.

In a new study published Tuesday in the BMJ, Brazilian researchers reported for the first time a link between Zika and arthrogryposis, a severe joint condition that's present at birth.

The condition leads to abnormal joint movement. It's a fairly common condition that is present in 1 out of every 3,000 babies.

The researchers looked at seven children who had been infected with Zika before they were born. Of the seven, six had joint deformities in both arms and legs. In one, only the legs were affected. The researchers said these cases of arthrogryposis were possibly connected to the nervous system, which is consistent with some of the other birth defects linked to Zika.

In April, the CDC confirmed that Zika is a cause of microcephaly, a condition in which the head is born abnormally small. Often, babies born with abnormally small heads suffer from underdeveloped brains and other serious complications including vision problems. Women who are pregnant are at risk of passing along the Zika infection to their unborn children.

Microcephaly was common, but not present in all of the children with arthrogryposis involved in the study.

Now that the link's been established in this small group, the researchers noted, more research needs to be done to explore the neurological component of the condition, as well as follow-up monitoring to see how the condition plays out as the children grow up.