The story so far: For almost two decades, Kathleen Folbigg, was behind bars, in Australia, for the death of her four very young children. Now, thanks to science, she can walk free.
On June 5, she was pardoned and released after an inquiry concluded that there was “reasonable doubt as to the guilt of Ms. Folbigg for each of the offences for which she was originally tried,” Nature reported.
The culprit, as it turns out, is a rare gene mutation that was not available as genetic evidence at the time of her original trial.
Who is Kathleen Folbigg?
Ms. Folbigg, 55, was dubbed “Australia’s worst female serial killer” after a jury found that she killed her children Caleb (19 days), Patrick (8 months), Sarah (10 months) and Laura (18 months) over a decade.
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The prosecution at the original trial alleged that she had smothered them despite there being no evidence of injuries or smothering. The trial convicted her on the basis of circumstantial evidence and focussed mainly on her diary entries, which described her hardships with motherhood. According to a BBC report, a snippet from an entry — “guilt about them all haunts me” — formed the base of the prosecutor’s case.
In 2003, she was convicted on three counts of murder and one manslaughter conviction.
What happened next?
Carola Vinuesa, currently a geneticist at Francis Crick Institute, London, was first made aware of Ms. Folbigg’s situation in 2018. She was tasked with sequencing genomes of Ms. Folbigg and her children, and determining if there was a genetic component that could have caused the mysterious deaths of the children.
In 2019, Dr. Vinuesa and her team tested Ms. Folbigg and her children’s DNA samples and found that she and her two daughters had a mutation in a gene called CALM2 which encodes a protein called calmodulin important for the functioning of the heart.
At the time, scientists could not determine if the mutation was harmful or of no particular significance. The appeal raised by Ms. Folbigg’s lawyers was quashed as Australian researchers said that the data presented was not definitive.
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In 2020, Dr. Vinuesa and her team compiled more detailed findings along with similar instances that have happened in the past and published it.
Finally, the authors of the paper and several other scientists rallied together, and filed a petition for another inquiry. The Australian Academy of Science supported the petition and a second inquiry was launched in 2022.
The CALM genes
There are three CALM genes (1-3) that encode a protein called calmodulin. This protein is multifunctional as it helps with binding and moving calcium within cells. It is especially important for heart function as it is instrumental in allowing and prohibiting calcium channels to open and close in cardiac muscle cells, thereby aiding the rhythmic contraction of the heart.
It is an essential protein that is vital for human survival.
The protein also has an extraordinary track record of conserving its amino acid sequence across all vertebrates which initially led to the assumption that any mutation to the genes would be lethal.
However, as genome sequencing became more advanced and prevalent, scientists found mutations in CALM genes.
These mutations are extremely rare and severe. It manifests early in life with the median age of the first cardiac event being 4 years. At least 27% of people carrying this mutation have died due to sudden cardiac death, according to a 2019 study that assessed 74 children.
Any medical complications arising due to the mutations in any of these three genes are called Calmodulinopathy.
What is the genetic mutation that affected Ms. Folbigg’s children?
After going through the reports of Ms. Folbigg’s children for the first time, Dr. Vinuesa realised that there could have been an underlying disease.
As the family’s genes were sequenced, she found out that the two daughters carried mutations in CALM 2 genes. As such, the protein produced by the mutated gene could not help in the movement of calcium through the cardiac muscle cells.
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As for the sons, the 2020 study did not find any mutated CALM genes. However, they did carry a mutated gene that encodes bassoon presynaptic cytomatrix (BSN) protein. The BSN is thought to be a scaffolding protein (a kind of protein that keeps several molecules together to hold them in an arrangement) found in brain cells. It helps organise the cytoskeleton, which is responsible for maintaining the cell’s structure, particularly at the ends of the brain cells where neurotransmitters are released.
Ongoing research has shown that half the mice population with the gene mutation died before six months and all of them suffered from epileptic seizures.
The part that science played
Once it became apparent that Ms. Folbigg may have been innocent, the next step was to take the scientific evidence to court.
The Australian Academy of Science was entrusted with being the scientific advisor. The Academy recommended close to 30 researchers. At least half of them presented evidence.
One of the expert witnesses was Michael Toft Overgaard, a protein scientist at Aalborg University in Demark.
“Science was heard in this case. The whole case has been a bit surreal for us as scientists to be part of,” he said while speaking to Nature.
During the inquiry, Dr. Overgaard and his colleagues were given time to explain the science behind their research to the lawyers. In one instance, he spent over five hours explaining how the mutation in the gene can hamper the functions of the calmodulin, he recalls. In another instance, the inquiry was put on hold so that the team could update their evidence from the most recent results.
Another expert witness was Peter Scwartz from the Italian Auxological Institute in Milan. He is the leading expert in sudden death caused by calmodulin mutations and has advised nearly 40 medico-legal cases, mostly in the U.S. He applauded the efforts of the Australian justice system saying that by involving experts from all over the world, the academy made sure that the evidence presented was the most recent.
What happens now?
As of last week, Ms. Folbigg was granted an unconditional pardon by the Governor of New South Wales. This, however, does not revoke her conviction which can only be done by the Court of Criminal Appeal. If it is overturned, she could sue the Australian government for wrongful conviction, the BBC report said.
The details of this case have highlighted how scientific evidence can help legal systems. While the entire ordeal may seem like an episode out of the American TV show Bones, Anna-Maria Arabia, the head of the Australian Academy of Science, said that it should promote a more “science-sensitive legal system” where advances in science can help shed light on past and present cases.
