Mucopolysaccharidosis type II (MPS II) is a carbohydrate metabolism disorder passed down from father to son and affects almost only men. It causes unique facial features, a big head, hydrocephalus, liver and spleen enlargement (hepatosplenomegaly), an umbilical or inguinal hernia, and hearing loss.
Moreover, people with this condition may also have deformed joints and problems with the valves of their hearts. MPS II is caused by changes in the IDS gene and is passed down through the X chromosome.