People who have non-functioning genes may not always have health problems.

David van Heel of Queen Mary University of London, Richard Durbin of the Wellcome Trust Sanger Institute in Hinxton, UK, and their colleagues sequenced the part of the genome that encodes proteins from more than 3,000 healthy adults whose parents were closely related (often first cousins). The team found that 821 individuals carried rare genetic variants that would be expected to cause the loss of function of certain genes. When the researchers examined the participants' health records, they found no links between the loss-of-function genes and clinical effects. One pregnant mother lacked a functional PRDM9 gene, which is required for fertility in mice, but the non-functioning gene had no impact on her health.

Non-functioning genes in adults may not be as clinically important as previously thought, the authors say.

Science http://doi.org/bc3x (2016)