Hutchinson's teeth. Close-up of the teeth of a patient with Hutchinson's teeth, a sign of congenital syphilis. Syphilis is a sexually transmitted infection caused by the spirochete bacterium Treponema pallidum. Congenital syphilis is present at birth in a child born to a mother with the disease. It is characterised by teeth that are smaller and more widely spaced than normal and with notches on their biting surfaces.