Fucosidosis

The purpose of this observational research study is to learn more about the natural history of fucosidosis, its symptoms, and how it develops over time. This study intends to collect information from participants diagnosed with fucosidosis; however, this study does not include any medication or treatment other than the usual medical care provided to study participants. The information collected in this study will be used to help understand the disease characteristics of fucosidosis; with this information potentially being able to help design future studies and treatments for this disease. There is currently no approved treatment for patients with fucosidosis. The study consists of 2 parts: a) Part A - retrospective data collection, and b) Part B - prospective data collection.