A doctor accused of failing to spot signs that Baby P was being abused is said to be "suicidal" and unfit to appear before a disciplinary hearing.
Dr Sabah Al-Zayyat saw 17-month-old Peter Connelly at St Ann's Hospital in Haringey days before his death in 2007.
She is accused of failing to carry out an "adequate examination", investigate his injuries or admit him to hospital. The GMC could ban her from UK working.
Peter's mother and two men have been jailed for their part in his death.
Counsel for the GMC, Rebecca Poulet QC, said she received a report last night from a doctor who had examined Dr Al-Zayyat.
The consultant psychiatrist wrote: "In my opinion, Dr Al-Zayyat has become so seriously ill that she is unfit to defend herself before a public hearing and unfit to instruct her solicitors.
"The pressure on her has been such that her mental health has broken down completely, and the possibility of suicide is a very real one."
Baby Peter died in August 2007 at his home in Edmonton, north London.
A post-mortem examination found he had suffered multiple injuries. He had received 60 visits from authorities.
He was already on the local child protection register at the time he was seen by Dr Al-Zayyat, a locum consultant community paediatrician at St Ann's Hospital, two days earlier.
The prosecution in the trial of the two men suggested it was likely he had already suffered significant injuries, including a broken back and ribs, at this point.
The trial heard that Dr Al-Zayyat noted bruises on his body, face and back, but told police she did not carry out a full examination because the child was "miserable and cranky".
She denied that he could have had a broken back at this point.
Commenting on the current General Medical Council hearing, Dr Al-Zayyat said: "In my 28 years as a paediatrician I have been devoted to the care of children and have always tried to do my best for them.
"I have been and remain deeply affected by the shocking and tragic circumstances of baby Peter's death.
"It would be inappropriate for me to comment any further until the hearing concludes."
The GMC hearing in London, which is scheduled to continue until mid-March, will look at whether Dr Al-Zayyat failed to diagnose abuse.
In addition, it will investigate whether she broke the rules by applying for a new job in the Irish Republic without informing the GMC, or telling her prospective new employer about the restrictions on her practice already imposed in the wake of the trial.