Embryologic development of epidermal ridges and their configurations.

The configurations of epidermal ridges that comprise dermatoglyphic traits are, in many respects, a history of the developmental period during which the ridges form. In 1892 Sir Francis Galton [l] demonstrated that epidermal ridge configurations did not change throughout postnatal life. The fact that ridge configurations were not affected by environment or by age has been an important framework in genetic studies. In 1936, Cummins [2] reported the association of unusual dermatoglyphics with Down syndrome. Confirmation of his findings [3_ 51 demonstrated the potential value of dermatoglyphics in clinical medicine. While not diagnostic alone, dermatoglyphics have been a valuable aid when clinical diagnosis was in doubt. Unusual dermatoglyphics now have been associated with congenital defects of both genetic and environmental origin [6]. Schaumann and Johnson [7] have noted that dermatoglyphics associated with congenital defects are significant markers of prenatal events. Yet, at present little is known about the atypical developmental processes that have produced these associations. The precise configuration of epidermal ridges and minutiae is determined at a very early embryonic age, around 10 weeks postfertilization. Accordingly, an understanding of the prenatal morphogenesis of dermatoglyphic traits is fundamental to our interpretation of their variation and their relationship to birth defects. The developmental history of dermatoglyphic traits requires first a background in the normal developmental chronology of prenatal hand. Second, it includes an understanding’of the development of epidermal ridges, the basic building blocks of dermatoglyphic traits, and factors that may influence ridge configuration. The developmental basis of dermatoglyphic traits is fundamental to a better understanding of their variation and relationship to congenital defects.