The study aims to establish whether Sanfilippo disease can be treated with a chemical found in soya beans.
Diagnosed in childhood, it is rare and fatal condition that affects around 150 children in the UK.
The study recruited 22 patients, with monitoring of the final patient due to finish in July. Results from the study will be published later this year.
You can read more about the new treatment for Sanfilippo disease on the CMFT Research & Innovation website.