Background: Mucopolysaccharidosis type II (MPS II). also known as Hunter syndrome. is a rare X-linked recessive disease caused by a deficiency of the lysosomal enzyme iduronate-2-sulfatase (IDS). which activates intracellular accumulation of nonmetabolized glycosaminoglycans such as heparan sulfate and dermatan sulfate. https://www.roneverhart.com/Flair/