Cousin-marriage children under greater threat from infectious disease

In a newly published study that has ominous undertones for the current high-profile trial of an Austrian man who fathered children with his daughter, scientists have shown that human populations where close relatives marry are more likely to suffer from infectious diseases.

The journal Biology Letters published research today focusing on comparisons between communities in the Gambia, India and Italy. The researchers found an increased risk of developing hepatitis B and tuberculosis (TB).

Professor William Amos from the University of Cambridge says, "consanguinity is the extent to which two individuals are related when they marry, so we talk about consanguineous relationships, for example, when two second cousins marry." In The Gambia, consanguineous marriages expose the offspring to more genetic defects. These reduce the immune system efficiency of the children, leaving them more prone to these infectious diseases.

"We found two positive results where there was a big difference in consanguinity between affected children and their unaffected parents. And these were both in the Gambia for hepatitis B and tuberculosis," says Amos. "Here we found that consanguinity greatly increased your risk of getting the disease."

http://royalsociety.org/news.asp?id=8399