Human Embryology and Teratology
Teaching text 20: Teratology, diagnosis, therapy 1: Teratology
Teratology, diagnosis, therapy
Teratology
Teratology is the study of congenital malformations and their causes. Malformations are macroscopically recognizable structural deviations which are present at birth and are due to abnormal developmental processes. Congenital anomalies comprise both macroscopic and microscopic defects. They include errors of metabolism and function as well as abnormalities at cellular and molecular levels.
Causes. A teratogen is a factor which can produce malformations or anomalies in an embryo or fetus. According to current knowledge, about 10% of malformations are due to environmental factors, 25% are due to genetic factors, and 65% are of unknown origin. In the latter group, many factors may play a role (multifactorial causation). It is thought that, to a degree, all developmental anomalies have many causes.