The U.S. doctor who has offered to treat terminally ill Charlie Gard has attended a meeting at Great Ormond Street Hospital (GOSH) to decide whether the baby should travel to America for therapy.
He further noted that the small number of people with Charlie's rare genetic condition, mitochondrial DNA depletion syndrome, would make robust clinical trials hard.
Charlie's parents are battling to take their child to the U.S. to receive nucleoside therapy, and Hirano's visit is part of their ongoing battle with Great Ormond Street hospital.
Hirano's research focuses on mitochondrial diseases and genetic myopathies and he has treated others with conditions similar to Charlie's.
Mr Justice Francis has considered the couple's latest claims at preliminary hearings in the Family Division of the High Court in London over the last few days.More news: Human remains found in Bucks County search for missing men
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The mother, Connie Yates, told the Press Association that doctors at Great Ormond Street wanted to turn off Charlie's life-support but decided not to after the White House intervened. The hospital says Charlie should be allowed to die with dignity. The case attracted global attention after Pope Francis and President Donald Trump weighed in.
Gard's parents want to take him to the United States to give him an opportunity to undergo an experimental therapy.
Charlie's parents, who are in their 30s and come from Bedfont, west London, have already lost battles in the High Court, Court of Appeal and Supreme Court in London.
Hirano will assess the situation Monday and Tuesday.
Francis will then consider information from Hirano to inform a decision from the court, which he has said he hopes to render by July 25.
The case returned to the High Court following reports of new data from healthcare specialists who suggested that Charlie's condition could improve with the treatment.