Iduronate-2-sulfatase

Iduronate-2-sulfatase (I2S) is an enzyme that plays a crucial role in the lysosomes of animals, including humans. It is involved in the breakdown of glycosaminoglycans (GAGs), specifically dermatan sulfate and heparan sulfate.

Function

Iduronate-2-sulfatase is responsible for the hydrolysis of the 2-sulfate groups of the L-iduronate 2-sulfate units of dermatan sulfate and heparan sulfate. These complex molecules are broken down within lysosomes, the 'recycling centers' of cells, where they are degraded and their components are reused by the cell.

Clinical significance

Deficiency of I2S is associated with a rare genetic disorder known as Hunter syndrome (Mucopolysaccharidosis type II). This is an inherited condition in which the body is unable to break down certain complex molecules, leading to a range of symptoms including developmental delay, skeletal abnormalities, and organ enlargement.

Genetics

The gene that encodes I2S is located on the X chromosome, which means that Hunter syndrome is an X-linked recessive condition. This means that males are typically affected, while females are usually carriers of the condition.

Treatment

Treatment for Hunter syndrome involves managing the symptoms and improving quality of life. Enzyme replacement therapy, in which synthetic I2S is administered, can help to break down the accumulated GAGs and alleviate some of the symptoms.

See also

• Lysosomal storage disease
• Mucopolysaccharidosis
• Enzyme replacement therapy