the distribution of subtypes varies between countries. in europe and the united states, 60–80% of people with guillain–barré syndrome have the demyelinating subtype (aidp), and aman affects only a small number (6–7%). in asia and central and south america, that proportion is significantly higher (30–65%). this may be related to the exposure to different kinds of infection, but also the genetic characteristics of that population. miller fisher variant is thought to be more common in southeast asia.