Out of the Blue: De Novo Mutations

As we have seen, clinical genetic counseling provides tools for understanding how genetic mutations carried by one or both parents are passed down to offspring. But a child can also be diagnosed with a mutation that is not seen in either of the parents’ genetic sequence. Recent research about the provenance of this type of hereditary abnormality—what scientists call de novo mutations—has made it possible to pinpoint exactly when such variations first appear in a developing embryo.