Developing a first complication. The curves show the percentage without a first complication during follow-up. The small vertical lines represent censored data (follow-up till the vertical line without development of a complication). A. Age at time of the first complication is depicted for the NH cohort and the ERT cohort. B. The time to the first complication is shown based on the median ERT duration for the ERT cohort only: patients receiving ERT more than 4.2 years (13M/16F, age at start of ERT 40.1 (15.9-71.5) years) or less than 4.2 years (14M/15F, age at start of ERT 41.2 (15.2-60.5 years)). Of note, in the analysis ERT duration was included as a continuous variable.