A Genetic Mutation That Causes Humans to Walk on All Fours

In 2005, scientists discovered a few families in Hungary where some of the adults only walked on all fours. Few understood the causes of this rare condition, called Unertan syndrome. Some scientists speculated that the quadrupedal people had simply never learned to walk upright due to learning disabilities and lack… » 6/02/08 8:00am 6/02/08 8:00am