When Alex Mickler's younger sister Emily was diagnosed with Batten disease at the age of seven, he didn't quite understand what that was.
By the time she was diagnosed in 2017, Emily — who Alex and his family describe as a "friend magnet"— had already become blind, and they had been searching for the cause for three years.
"Mum and dad, they sat down and told us, me and Ben [brother], they explained what it was and what was going to happen to her, and I think that I knew what was going to happen then," Alex recalled.
