existing at birth: describes an unusual condition present at birth.
Merriam-Webster Online Dictionarycongenital (adjective)
a) existing at or dating from birth - congenital deafness
b) constituting an essential characteristic - inherent congenital fear of snakes
c) acquired during development in the uterus and not through heredity - congenital syphilis
being such by nature - a congenital liar innate