On March 1, 1999 a woman Australian Phone call Kathleen Folbig found her 18monthold daughter Laura dead in her cradle. This would be another case of a rare but mysterious syndrome called crib death were it not for a fact established by police: Laura was Kathleen’s fourth child, found dead in the crib by her mother.
Ten years earlier, in 1989, their first child, Kaleb, had died in the same way. And two years later, in February 1991, the second child, Patrick, was also found dead in his cradle. On August 30, 1993, her third child, Sarah, also died in her crib. The autopsies found nothing abnormal or signs of violence in the four children.
A mother’s diary, in which she describes her distress with her children’s work and her guilt for not being a good mother, was also used as evidence, leading the children’s father to believe in the woman’s guilt. Kathleen was sentenced to 40 years in prison in 2003 and became known as Australia’s top child serial killer.
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Australian Kathleen Folbigg has been sentenced to 40 years in prison for the murder of her four children. Photo: DAVID GRAY / Portal
Conviction without direct evidence of the murders has been controversial. In 2018, the defense turned to geneticists looking for another explanation for the four deaths. Although there are no known genes involved in crib death syndrome, the scientists thought it would be a good idea to sequence Kathleen’s genome.
Analyzing the genome, the scientists found a mutation in one of the genes for calmodulin, a protein that can bind calcium and is involved in the relaxation of heart muscle cells. The problem was that this mutation was new and hadn’t been found in any other human, so it was difficult to know if it could be responsible for the children’s deaths. Nevertheless, the scientists recommended sequencing the genomes of the dead children. Fortunately, blood and cell samples from the children were available at several hospitals and it was possible to sequence their genome and show that the mutation had passed to the children.
In the years that followed, scientific papers emerged showing that other mutations in the calmodulin gene caused heart problems, but in no case was this specific mutation present. When there was an initial review of the conviction, the judge ruled that there was insufficient evidence of this mutation to overturn the conviction. Some data were missing linking this specific mutation in the calmodulin gene to a problem in heart cells.
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In 2021, a scientist decided to address this problem and for this purpose to isolate the human calmodulin gene and introduce the exact mutation found in mother and children into the gene. He produced the mutated calmodulin from the mutated gene and tested its properties in heart cells. In a first step, he demonstrated that this mutation prevents calmodulin from binding to the calcium that is essential for its function. He then showed that this mutant calmodulin changes the function of heart cells and causes changes in the process of muscle contraction and relaxation. These data prove that the mutation present in the mother and the dead children can be the cause of the cardiac arrest that led to the death of the children in the crèche.
The scientists have now created a dossier with all the data and asked the lawyers to reexamine the case. The Australian Academy of Science was involved in the review process and 90 geneticists signed a petition confirming the robustness of the data. They hope this new data can overturn Kathleen’s conviction. She has always maintained her innocence. Most likely, the culprit for the deaths is the mutated calmodulin gene that is present in the mother and passed on to the children.