Middlesex County prosecutors dropped a murder charge Thursday against a former MIT worker who had been accused of killing his 6-month old son at his Malden home in 2010.
In a court filing, District Attorney Marian T. Ryan’s office wrote that the case against Geoffrey Wilson, 36, could not go forward after the state medical examiner and prosecutors received new information about the family’s medical history.
That history, which the parents of the boy, Nathan Wilson, did not know about at the time of the 2010 death, could “possibly have played a role,” prosecutors wrote.
After genetic testing of family members, a review of relevant medical records, and consultation with specialists in fields including genetics and forensic pathology, the medical examiner revised his finding on the manner of death from homicide to “could not be determined,” prosecutors wrote.
Wilson’s lawyer, J.W. Carney Jr., said in August that Nathan’s mother and grandmother have a rare genetic defect that can cause weaknesses in collagen, which would make a person more susceptible to ruptures of arteries or veins.
“It was every parent’s nightmare when Geoff Wilson was charged with murdering” his son, Carney said Thursday.
“All five of our medical experts offered the opinion that Nathan Wilson had died of natural causes and not Shaken Baby Syndrome.”
In a statement, Ryan said the medical examiner had initially ruled that Nathan died from shaking injuries to his head.
“As the case proceeded, defense counsel presented new information about the family medical history that was previously unknown to both the Commonwealth and the child’s parents,” Ryan said.
“That information led Dr. [Peter] Cummings at the Medical Examiner’s Office to revise his prior findings.”
Ryan said the charge was being dropped in the interests of justice. Wilson had been free on bail.
No one answered on Thursday evening at a number listed for Wilson, who worked at the MIT Media Lab at the time of his arrest. He no longer works there, said a spokeswoman for the Massachusetts Institute of Technology.
Thursday’s development could play a role in another high-profile case involving an infant death.
The Wilson case has been cited by lawyers for Aisling Brady McCarthy, an Irish nanny charged in Middlesex County with murder in the January 2013 death of a 1-year-old girl she had been caring for.
McCarthy’s lawyers are seeking to bar the testimony of Dr. Alice Newton, a specialist on child abuse cases who has determined that 1-year-old Rehma Sabir, who McCarthy is accused of killing, died of abusive head trauma. Newton had made the same determination in the Wilson case.
“The opinions expressed by Dr. Newton in the Wilson case are strikingly similar to those expressed by her in this case,’’ McCarthy’s lawyers have said in court papers.
Melinda Thompson, a lawyer for McCarthy, learned from a reporter on Thursday night that prosecutors had dropped the Wilson case.
Asked if she felt that the development would help McCarthy, Thompson said, “I sincerely hope that it does.”
Prosecutors made no mention of Newton in Thursday’s court filing, and a spokeswoman for Ryan declined to comment when asked whether the Wilson decision would affect McCarthy’s case.
During a court hearing earlier this month, Newton defended her work in the McCarthy case, testifying that the 1-year-old in the nanny’s care “was subjected to violent force” and that “I believe she was shaken and slammed.”
She declined to comment on Thursday through a spokeswoman for Massachusetts General Hospital, where she is on the staff.
McCarthy’s lawyers have contended that the child suffered bone injuries weeks before her death when she was out of the country and not in McCarthy’s care.Martin Finucane and Peter Schworm of the Globe staff, and Globe correspondent Zachary T. Sampson contributed to this report.