EVALUATION OF A DERMATOGLYPHIC INDEX TO DETECT PLACENTAL TYPE VARIATION IN MZ TWINS

A dermatoglyphic index, which was previously used retrospectively to a ssess relationships between placental type in MZ twins with other vari ables, was tested for verification in two new separate samples of twin s of known placental type. In both a French twin sample (19 monochorio nic and 24 dichorionic) and the U.S. twin sample (49 monochorionic and 22 dichorionic), dermatoglyphic index scores were higher in monochori onic than dichorionic pairs. The difference in scores attained statist ical significance when the two new samples were pooled. It is conclude d that although the index cannot be used retrospectively to class-fy a n individual MZ twin pair, an association of the placental type dermat oglyphic score with another variable in a group of MZ twins without an y placentation information provides support for continuing to investig ate prenatal effects on the associated variable. (C) 1997 Wiley-Liss, Inc.