Lysosomal storage diseases are rare inherited metabolic disorders caused by defects in the function of lysosomes, the enzymes in cells responsible for digesting molecules and processing waste. 

Around 50 different conditions that fall under the category of lysosomal storage disease, including Farber disease, Fabry disease, Hurler syndrome, Gaucher's disease, and Wolman disease. However, the origin of all lysosomal storage disorders is the abnormal accumulation of substances inside the lysosome. 

Signs and symptoms of a lysosomal storage disease vary according to the condition but may include developmental delays, dementia, deafness, seizures, and blindness. 

There are no cures for lysosomal storage diseases, but treatment usually focuses on medication to increase the levels of deficient enzymes. Drug classes often used to treat lysosomal storage diseases are cystinosis agents, mucopolysaccharidosis (MPS) agents, Fabry disease agents, Pompe disease agents, other ophthalmologicals, topical and Gaucher's disease agents.