MDDS caused by mutations in RRM2B have been recorded. , there was only one experimental treatment for MDDS based on nucleoside supplementation, used on mice and human patients carrying a mutation in a different gene (TK2), which also impairs the synthesis of nucleosides in mitochondria causing a less severe form of MDDS. The hospital's ethics committee advised in November 2016 that Charlie should not be given a tracheostomy. In mid-December, he began having persistent seizures as his brain function deteriorated. He had become deaf, his heart and kidneys were failing, and he could no longer breathe or move independently. It was unclear whether he could feel pain. Experimental nucleoside treatment In December 2016, Michio Hirano, chief of the Division of Neuromuscular Disorders at Columbia University Medical Center, and an attending neurologist at New York–Presbyterian Hospital, who had worked on nucleoside therapy in collaboration with researchers in Italy, Spain and Central America, administering the therapy to 18 human patients, was contacted. Charlie's records were sent electronically to Hirano on 30 December, and he and a member of the GOSH medical team discussed the case by telephone. Both doctors agreed that the experimental treatment was unlikely to help if there was irreversible brain damage. Hirano and the GOSH medical team continued to email and discuss the treatment by telephone. Hirano said there was a "theoretical possibility" that the treatment would provide some benefit, but that he needed a baseline MRI to rule out "severe brain involvement". An MRI was performed and seemed to show no structural damage to the brain. On 9 January 2017, notes kept by GOSH doctors recorded that the team intended to attempt the nucleoside treatment at GOSH in the next few weeks. One of the doctors applied to the hospital's ethics committee for approval. A committee meeting was scheduled for 13 January, and Charlie was provisionally scheduled for a tracheostomy on 16 January. GOSH invited Hirano to examine him in January, but he did not examine Charlie until July. On 9 or 10 January, Charlie began having epileptic seizures, which continued until 27 January. These were deemed likely to have caused epileptic encephalopathy (brain damage), and the 13 January ethics committee meeting was postponed. On 13 January, the GOSH doctors informed Charlie's parents that the brain damage had made the experimental treatment futile, and in light of the risk that he was suffering, they withdrew their support for