This is a non-interventional, retrospective study of participants diagnosed with late infantile or juvenile MLD whose data will be retrieved from existing health records.~Data from all participants, diagnosed with MLD from 01 January 2000 to 31 December 2022 will be collected from health records, including demographic and clinical data from the pre-diagnosis until the date of data collection or death, whatever occurs first.~The study will be conducted in Spain. The overall duration for data extraction is up to approximately 23 years.
The main aim of this study is to learn about metachromatic leukodystrophy (MLD) in children and teenagers in Spain. This includes checking the number of new MLD cases and the frequency of children with MLD in 2022 in Spain.~There is no treatment involved in this study. Participants' data will be taken from their medical records (charts), which were already collected as a part of their routine care between 01 January 2000 and 31 December 2022.