Lysosomal Storage Disorders are a group of diseases in which the function of the lysosome, the part of the cell that degrades and ‘recycles’ cellular debris, is impaired. Most LSDs are rare recessive disorders, whereby a child inherits two mutant versions of lysosomal gene, one from each parent, which results in an absence or dysfunctional lysosomal protein. The Orphan Disease Center focuses on a subgroup of LSDs with a specific dysfunction in the breakdown of glycosaminoglycans, also known as mucopolysaccharides. This family of disorders is commonly referred to as Mucopolysaccharidoses.