Table 1.

Description of themes

Theme	Sub-theme	Illustrative words/phrases used*
Quality of life	Future	“improve life”, “normal life”, “make life easier”, “too old for gene therapy to work?”, “change in personality”
	Symptoms	“improve cognitive function”, “alleviate symptoms”, “avoid difficulties”, “how would they adapt to change in themselves?"
	Tolerability	“method of delivery”, “tolerability of procedures”, “anxiety of child”, “pain”, “newness”
Outcomes	Cure	“address root cause”, “better future”, “reduce caregiver burden”, “help”, “fix”, “root level”, “effectiveness”, “treatment”
	Safety	“risks”, “unintended consequences”, “change child”, “side effects”, “working then stopping”
Feelings	Support	“hopeful”, “prayers”, “interesting”, “positive”, “exciting”, “worth a try”, “optimistic”, “yes”, “grateful”, “curious”
	Caution	“uncertain”, “concern”, “unsure”, “unknown", “ethics”, “frightening”, “distrust”, “nervous”, “sad”, “newness”

^*illustrative words/phrases are all direct quotes from participants