The pathologist's perspective of genetic disease. Malformations and dysmorphology.

The pathologic approach to the study of malformations and congenital abnormalities emphasizes the importance of careful dissection and pathologic studies. Concepts and terms of morphogenesis as defined by the International Working Group are presented. The developmental field is the central concept of a malformation. Malformation syndromes, disruptions, sequences, deformations, dysplasias, and associations are presented. The significance of fetal hydrops and short umbilical cord is discussed. Pathologic studies in chromosome defects suggest pathologic markers for some chromosome abnormalities.