Other names: GUSB Deficiency; MPS VII; Sly Syndrome

Mucopolysaccharidosis VII (also known as Sly Syndrome, MPS VII and GUSB Deficiency) is a rare genetic disorder caused by the lack of the enzyme beta-glucuronidase, which breaks down the long chain sugar molecule called glycosaminoglycans (GAG).

Usually GAG is broken down by the enzyme beta-glucuronidase into simpler molecules that the cell can reuse.  In MPS VII there is not enough enzyme produced, or the enzymes do not work properly, so the GAG is not broken down and therefore starts to accumulate within the cells. This build up of GAG causes progressive, permanent damage to the cells which produces the symptoms and physical problems of MPS VII which can range from mild to severe.

Symptoms and physical problems include

• skeletal irregularities
• short stature
• joint stiffness
• eye issues including corneal clouding, loss of peripheral vision and night blindness
• hearing problems
• developmental delay and a progressive decline developmental function
• respiratory issues
• enlarged liver and spleen
• heart problems

Drugs used to treat Mucopolysaccharidosis Type VII