Mucopolysaccharidosis II (MPS II),
also commonly known as Hunter syndrome, is a condition that occurs almost exclusively in males. Affected individuals typically have distinctive facial features, a large head, hydrocephalus, an enlarged liver and spleen, umbilical or inguinal hernia, and hearing loss. Individuals with this condition may have joint deformities and heart valve problems. MPS II is caused by mutations in the IDS gene.
There are two types of MPS II, called the severe and attenuated types. While both types affect many different parts of the body, people with the severe type also experience a decline in intellectual function and a more rapid disease progression. The life expectancy for people with the severe type is 10 to 20 years. Individuals with the attenuated type typically live into adulthood and their intelligence is not affected. Heart disease and airway obstruction are major causes of death in people with both types of MPS II. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.