I don't think the breakdown mean much because I would bet many of those discontinued ERT in the last a few years were involuntary due to Fabrazyme shortage, thus it wouldn't tell you true demand under normal condition.
Just add one thing about these patients with LSDs, it is not homogenous population, some would have no problem getting off ERT for long period of time, some couldn't live normal life without ERT. So, it adds complexity to clinical trial and data interpretation due to small population.
Market Data 
Markets 
AI
