Glossary A Arylsulfatase B (also known as ASB or N-acetylgalactosamine 4-sulfatase): A lysosomal (see lysosome) enzyme responsible for breaking down the glycosaminoglycan (GAG; see glycosaminoglycan) dermatan sulfate. In MPS VI (see mucopolysaccharidosis type VI), the absence of this enzyme renders cells unable to break down GAG, leaving behind a partially degraded metabolic (see metabolism) byproduct. ASB: see arylsulfatase B. C Cell: The smallest structural unit of an organism that is capable of independent functioning. Clinical study: Also known as a clinical trial, a patient study is an experiment testing the effectiveness and safety of a new drug. A typical patient study compares the improvements in a group of patients receiving the new drug compared with another group that is not. Connective tissue: A type of tissue in the body that forms the binding and support for organs and other functional tissues. Examples of connective tissue include bone, cartilage, skin, blood vessel walls, and fat. D Dermatan sulfate: A type of chemical known as a glycosaminoglycan (GAG; see glycosaminoglycan) that is naturally produced in the body. It is a jelly-like substance that forms the foundation for certain tissues known as connective tissues (see connective tissue). Like many other substances in the body, it is in a continuous cycle of production and degradation. When its degradation is disrupted it builds up, causing major organ dysfunction. E Enzyme: A chemical naturally found in the body that performs a specific function. People with MPS VI lack a critical enzyme whose role is to break down excess waste products (GAG) in cells. In the absence of this enzyme, the GAG builds up, eventually leading to severely abnormal growth and disability. Enzyme replacement therapy (ERT): The latest development in the treatment of certain conditions that arise when the body does not produce enough of an enzyme (see enzyme). In enzyme replacement therapy, the body is supplied with a replacement for the enzyme that it cannot produce. The replacement enzyme is biochemically identical to the deficient enzyme and thus is believed to perform the exact same function. ERT has shown positive results in the treatment of certain diseases: Gaucher type I, Fabry, MPS I, and MPS VI. ERT can impact the progression of a disease that is caused by a deficient enzyme. NAGLAZYME® (galsulfase) (see NAGLAZYME) is an example of ERT. G Gene: A length of DNA in a specific location on a chromosome which contains the information necessary for determining a certain feature of an organism (eg, the gene for blue eyes). In MPS VI (see mucopolysaccharidosis type VI), there is a defect in the gene that directs the production of an enzyme (see enzyme), arylsulfatase B (see arylsulfatase B). Because of the defect in the gene, the body is not able to produce enough of this enzyme (see enzyme). Genetic: Referring to the processes and functions of genes, particularly their hereditability. A genetic disease is one that is inherited and passed down in genes. It typically arises at birth. Glycosaminoglycan (GAG): A substance found throughout the body. GAG is naturally produced from proteins and sugars. In a healthy person, excess GAG is broken down by enzymes (see enzyme). In a person with MPS VI (see mucopolysaccharidosis type VI), this does not happen. Instead, excess GAG builds up inside cells, leading to cell and tissue damage in virtually every organ in the body. I Intravenous (IV) infusion: Introduction of a solution into the body through a vein for therapeutic purposes. L Lysosomal storage disorder (LSD): A class of genetic (see genetic) diseases whose characteristic feature is the body’s inability to expel waste materials from cell lysosomes (see lysosome). In LSDs, waste materials that cannot be properly broken down are trapped within the lysosomes of cells, often resulting in cellular malfunction and cell death. MPS VI (see mucopolysaccharidosis type VI) is an LSD. Lysosome: A cellular organelle (see organelle) responsible for breaking down metabolic (see metabolism) waste products into smaller parts that can pass out of the cell. M Maroteaux-Lamy syndrome: See mucopolysaccharidosis type VI (MPS VI) . Metabolism: The process by which cells use energy to produce building blocks to function and survive. “Metabolic” describes any of these processes. Mucopolysaccharidosis type VI (MPS VI): Also known as Maroteaux-Lamy syndrome, MPS VI is a lifelong disease that affects growth and development in virtually every part of the body. MPS VI is caused by a genetic defect that prevents the production of a certain enzyme called arylsulfatase B. Over a period of time, the deficiency in arylsulfatase B begins to affect growth. An affected person may experience short stature, stiff joints, reduced mobility, breathing problems, deformed facial features, heart problems, and a multitude of other symptoms. There is a wide range of variability among people with MPS VI. While many with the disease will begin to show symptoms in early childhood, others will not show symptoms until later. Because MPS VI is a progressive disease, however, all will eventually experience severe and debilitating symptoms. Without this enzyme, MPS VI is a debilitating and life-threatening disease. N N-acetylgalactosamine 4-sulfatase: See arylsulfatase B. NAGLAZYME® (galsulfase): A breakthrough therapy in the treatment of MPS VI that is already changing patients’ lives. NAGLAZYME is the only ERT (see enzyme replacement therapy) for MPS VI. The treatment works by providing the body with an enzyme it needs in order to maintain healthy cell function. O Organelle: Just as animals have organs, individual cells that make up those organs have structures called organelles. Organelles are responsible for the chemical processes that the cell must perform in order to function and survive. In MPS VI (see mucopolysaccharidosis type VI), the cellular organelle known as the lysosome malfunctions. Organ system: A collection of bodily organs grouped by structural or functional similarity. For instance, the central nervous system, composed of the brain and nerves, is an organ system.