This was apparently reported in a Digest of Selected Medical Law and Bioethics Cases :
The judgment at first instance [Cagliari Assize Court, 10 March 1982], upheld on appeal, found the parents guilty of participation in an intentional homicide, finding this intention in the act of having accepted the risk of not preventing the death of their minor child.
The Court of Cassation [Ist Criminal Division, 13 December 1983] set aside the judgment of the Court of Appeal and referred it back to the Court of Appeal for a flaw in the judgment's reasoning as to the recognised existence of a homicidal intent...
...the Rome [Assize] Court of Appeal [13 June 1986] held the parents responsible for participation in the crime of manslaughter as an unintended consequence of the offence of violation of the duty of assistance owed to family members.
I am unaware whether the sentence was amended but would think that as the crime was changed from intentional homicide to manslaughter it would have been substantially reduced.