Kathleen Folbigg was sentenced to 40 years, later reduced to 25, in prison on charges of killing her four children. In the absence of solid forensic evidence, prosecutors at the time said she had suffocated the children, who died suddenly between 1989 and 1999.
A team of immunologists has found that the woman's two daughters shared a genetic mutation — called CalmM2 G114R — that can cause sudden cardiac death. The two sons, however, had a different genetic mutation, linked to epilepsy.