A woman has admitted suffocating her severely disabled son after suffering a breakdown.
Dylan Freeman's body was found in Acton, west London, on 16 August with a sponge in his mouth.
His mother Olga Freeman pleaded guilty at the Old Bailey to manslaughter by reason of diminished responsibility.
Three psychiatric reports said Freeman was suffering from a severe depressive illness with psychotic symptoms at the time of the killing.
Freeman attended Acton Police Station to report herself following the killing.
Officers later found Dylan in his mother's bed surrounded by toys.
Dylan had autism, Cohen syndrome - which is linked to abnormalities in many parts of the body - and significant difficulties with language and communication.
In the week leading up to the killing, Freeman had spoken about saving the world and being a Messiah, the Crown Prosecution Service (CPS) said.
Freeman appeared by video-link to enter her plea and will be sentenced on 11 February.
Speaking after the hearing, the CPS's Kristen Katsouris described the death as "tragic".
She added: "Olga Freeman had loved and cared for Dylan for many years, but the strain and pressures of her son's severe and complex special needs had built up and that, combined with her impaired mental health, led to heart-breaking consequences."
A post-mortem examination at Great Ormond Street Hospital recorded Dylan's cause of death as upper airway obstruction.
The Met Police said Freeman had spoken to friends about struggling with the responsibility of caring for Dylan.
On the night before his body was found, Freeman booked two seats on a flight to Tel Aviv and told her friend not to go into Dylan's room.
At the time of his death, his father, celebrity photographer Dean Freeman, was in Spain.
He described his son as "a beautiful, bright, inquisitive and artistic child who loved to travel, visit art galleries and swim".