Approach to congenital malformations
- Carlos A Bacino, MD, FACMG
Carlos A Bacino, MD, FACMG
- Professor of Molecular and Human Genetics
- Baylor College of Medicine
Major congenital malformations occur in approximately 3 to 4 percent of livebirths, although minor anomalies are more frequent. Birth defects can be isolated or present in a characteristic combination or pattern.
In ancient times, birth defects were believed to result from the action of supernatural forces . They were viewed as manifestations of evil and sometimes as signs of God's warnings for impending disasters. Even though the perception of birth defects differs from culture to culture, it has been attributed mostly to negative forces. These concepts have evolved from ancient times until the present, although superstitions persist in many cultures.
A more systematic study of birth defects began in the mid-20th century. This coincided with the recognition of the teratogenic effects of exposures to rubella infections and thalidomide during pregnancy.
The term "dysmorphology" was coined in the 1960s to define the study of abnormal features. This term is used to encompass the variability of normal physical traits, as well as pathologic features resulting from abnormal development. An individual with unusual physical features is said to be dysmorphic. Experts in dysmorphology are trained to describe patterns of abnormal traits and establish a diagnostic hypothesis based upon their appearance.
Specific terms are used to describe congenital abnormalities. The terms indicate how the anomalies were caused (table 1).
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- HISTORICAL BACKGROUND
- - Major
- - Minor
- - Amniotic band sequence
- PATTERNS OF DEFECTS
- Developmental field defect
- Mechanisms of teratogenesis
- Specific teratogens
- - Infectious agents
- - Maternal illnesses
- - Physical agents
- - Drug exposure
- Physical examination
- Laboratory studies
- INFORMATION FOR PATIENTS