A High Court judge is to analyse evidence about a seriously ill baby boy at the centre of a life support treatment dispute.
Doctors at Great Ormond Street Hospital (GOSH) in London believe it is time to stop providing life support treatment to Charlie Gard, however, the eight-month-old's parents want to be allowed to take him to the US where they hope he can be treated.
Charlie suffers from a rare genetic condition called mitochondrial depletion syndrome which causes progressive muscle weakness and means that he is deaf and unable to cry.
Medics believe that further treatment would unnecessarily prolonging Charlie's suffering.
But his parents, Chris Gard, 32, and Connie Yates, 31, want to keep him on life-support and have fundraised more than £1.2 million to take him to the US where it is hoped he could undergo nucleoside bypass therapy.
Charlie's parents hope the treatment would repair their baby's faulty mitochondrial DNA and help it synthase again by giving him the naturally occurring compounds that his body isn't able to produce.
Writing on the GoFundMe page to raise money to send her son to the US, Ms Yates wrote: "We just CAN'T let our baby die when there is something that might help him!
"We won't give up on him because he has a rare disease. He deserves a chance and he deserves a life as much as anyone else.
"If Charlie receives this treatment and it does work like the Dr in America thinks, it won't be just Charlie's life that has been saved, it will be many more children in the future, who are born with this horrible disease and it will open up other trials on other mitochondrial depletion syndrome's.
"He literally has nothing to lose but potentially a healthier, happier life to gain."
Mr Justice Francis began analysing evidence at a hearing in the Family Division of the High Court in London on Monday before deciding which option is in Charlie's best interests.
Barriester Sophia Roper QC, who is representing Charlie's parents for free said there is "no evidence" that he is regularly in pain.
On Monday Mr Justice Francis heard detailed medical evidence from the specialist who would oversee Charlie's treatment in the US.
The specialist suggested that treatment would be compassionate. He proposed a therapy which he said would provide a "small chance" of a meaningful improvement in Charlie's brain function.
"It may be a treatment but not a cure," he said, adding that Charlie was in the "terminal stage" of his illness.
"(Charlie) may be able to interact. To smile. To look at objects."
He said he proposed trying the the therapy for up to six months.
The judge had previously been given an overview of evidence at a preliminary hearing in March where a barrister representing GOSH gave some details of Charlie's condition.
Katie Gollop QC said doctors thought that a withdrawal of life support treatment would be in Charlie's best interests and told the judge: ''The hospital's position is that every day that passes is a day that is not in the child's best interests.''
Ms Gollop said Great Ormond Street specialists had considered the type of treatment Charlie's parents wanted him to have in America and decided against it.
Ms Roper told the judge: ''His parents believe that he is in much better shape than the hospital does.''
The court was told Charlie's parents are "utterly devoted" to him, with the judge describing the case as "one of the saddest" it had come across.
The judge was also told that Charlie would have to fly in an air ambulance with nurses if he went to America.