from the article on The Hills Have Eyes:

'Prior to filming, Aja and Levasseur had already conceived an idea for the mutants' appearance. "We based all our descriptions and directions on real documents, pictures and footage that we found on the effects of nuclear fallout in Chernobyl and Hiroshima", explains Aja. In addition, Aja and Levasseur spend extensive time with local residents living in the filming location of Palmdale to further grasp an accurate depiction of what the mutants would look like. Aja stated "Our biggest form of inspiration for the look of the mutant creatures came when we went to a Pogues concert in Chicago and observed the people around us."'

http://en.wikipedia.org/wiki/The_Hills_Have_Eyes_%282006_film%29

great film, incidentally. genuinely horrifying