Lysosomal disorders may refer to any of about 50 different genetically inherited, metabolic conditions caused by defects in lysosomal function.
The lysosomes are small sacs of enzymes that are found in each of the cells of our bodies and are responsible for digesting and recycling nutrients in the cell. Lysosomal disorders are often the result of one missing, deficient, or defective enzyme. Each of the enzymes within the lysosomes is critical for breaking down these nutrients, and if one is missing or not working effectively, the lysosome cannot function properly. The undigested products then build up, and may eventually kill the cell. Because many different conditions are classified as lysosomal disorders, the symptoms, diagnostic process, and treatment all vary. However, some potential symptoms may include developmental or mental delay, seizures, dementia, deafness, and blindness. Diagnosis often includes an enzyme assay to determine the level of enzyme function along with genetic testing in some disorders. Treatment often involves some form of enzyme replacement therapy in attempt to restore the defective or deficient enzyme. Bone marrow transplant is also a possibility in some cases.
Each individual type of lysosomal storage disorder is rare, however as a whole, they affect approximately 1 in 7,700 births making them a significant health issue. All forms are progressive, which means they worsen over time; however, the rate of progression, the severity of symptoms, and the organs in which they affect vary greatly amongst them. Almost all lysosomal disorders are inherited in an autosomal recessive manner except a few (Fabry disease and Hunter syndrome) that are inherited as X-linked disorders. A genetic counselor can help provide a better understanding of the underlying genetic causes and recurrence risks.