The French national birth-defect agency REMERA recently identified clusters of children born with malformed limbs in three rural regions in France. Each cluster has 3-8 children with malformations that include children with missing or deformed arms and hands.

The French public health department (Santé Publique France) originally suggested that these cases were not above what was naturally expected each year. Around 3-4% of children worldwide have a birth malformation.

Although genetic, chromosomal and environmental causes — such as medicines — can account for some of these malformations, in most cases the cause is unknown.

It is difficult to know if the type and number of these limb differences in France are to be expected or if they are cause for concern. This is made more difficult by the fact that the French birth-defects registry only covers 19% of the country’s births.