Researchers in Brazil are shedding some light on a possible association between the Zika virus and arthrogryposis, a condition that causes joint deformities at birth.
A research team based in Recife, the northeastern Brazilian city described as ground zero of the country’s Zika epidemic, studied detailed brain and joint images of seven children born with arthrogryposis. The children also had a diagnosis of congenital infection presumably caused by the Zika virus.
Microcephaly, characterized by abnormally small heads in fetuses and infants, has already been definitively linked to the Zika virus.
All seven children in the latest study showed signs of brain calcification, also seen in microcephaly patients, and there was no evidence of joint abnormalities. This led the researchers to believe that the arthrogryposis "did not result from abnormalities of the joints themselves, but was likely to be of neurogenic origin."
That means that the condition would involve cells that control the contraction or relaxation of muscles, leading to fixed postures in the womb and consequently joint deformities.
All seven children tested negative for the five other main infectious causes of microcephaly: toxoplasmosis (parasitic disease), cytomegalovirus (which can cause premature births and long-term health problems), rubella, syphilis, and HIV.
“Because this is an observational study, no firm conclusions can be drawn about the effect of the Zika virus on arthrogryposis,” the researchers said in a news release.
The inconclusive findings were published Tuesday in The British Medical Journal. The study authors say that further research is needed with a larger number of cases to study the neurological abnormalities that cause arthrogryposis.
But based on their observations, the researchers say that "congenital Zika syndrome should be added to the differential diagnosis of congenital infections and arthrogryposis."
