Decades-old DNA from the children of serial killer Kathleen Folbigg, including frozen organ tissue, has been analysed for an inquiry into her convictions, with nothing found in their genes that could explain sudden death.
"The commonest and most plausible genes which cause sudden death in infancy are not present in this family," Professor Jon Skinner told the inquiry on Monday.
Counsel assisting, Gail Furness SC, said a multidisciplinary panel of experts conducted genomic sequence testing on the babies' samples using technologies that had emerged since their mother's NSW trial in 2003.
Ms Furness said the results of genetic-related investigations at the time were normal and did not indicate the need for further testing - but significant advances have since been made.
Folbigg was jailed for at least 25 years after she was convicted of killing her four babies - Caleb, Patrick, Sarah and Laura - in the decade from 1989.
They died aged between 19 days and 19 months.
The 2019 inquiry is focused on medical advances and new research including into three or more infant deaths in the one family attributed to unidentified natural causes.
Material available for genetic testing included blood spots from each child taken at birth and kept at the Children's Hospital at Westmead, and tissue samples fixed in glass and wax block slides and held at the coroners court.
Kidney, liver, skin, skeletal muscle and heart tissue samples frozen at -80C from Patrick's autopsy in 1991, formalin-immersed brain tissue from Laura's autopsy in 1999 and a recent DNA sample from Folbigg herself were also produced to the inquiry.
Ms Furness said the expert reports from Sydney and Canberra found "no known pathogenic - capable of causing disease - or likely pathogenic variants in genes that could explain unexpected death" in any of Folbigg's four children.
Dr Alison Colley told the inquiry: "I think it's very important we started with a hypothesis-free (perspective) which means we were looking at all possibilities, all genes that could cause catastrophic events or infant demise".
The panel of clinical geneticists and genetic pathologists agreed they would have liked to have had a DNA sample from the father of the babies, Craig Folbigg, who refused to supply one.
But Professor Edwin Kirk said: "In the end, it didn't make any difference."
Dr Michael Buckley added: "We didn't identify any variant in the children that we were concerned about, that appeared to have been inherited from Craig, and the interpretation didn't hinge on his clinical sample".
Mr Folbigg has engaged lawyers to cross-examine his ex-partner when she testifies in the week from April 29. The 51-year-old did not take the stand at trial.
Her evidence will be limited to her personal diaries, which included comments such as baby Sarah who "left, with a bit of help" and Laura being "a fairly good-natured baby" which "saved her from the fate of her siblings".
Ex-NSW District Court chief judge Reginald Blanch QC, who is presiding over the inquiry, will prepare a report on its results for the NSW governor.
Australian Associated Press