THE PRENATAL EXCLUSION TEST FOR HUNTINGTONS-DISEASE - EXPERIENCE IN THE WEST OF SCOTLAND, 1986-1993

Information about the prenatal exclusion test for Huntington's disease (HD) has been given to an unselected series of couples who attended t he genetic counselling clinic from 1986 onwards. Ten couples underwent 13 prenatal tests during this period with expressed intention of stop ping a pregnancy if the result indicated a high risk (almost 50%) that the fetus carried the HD gene. Nine fetuses at nearly 50% risk of car rying the HD gene were identified but only six such pregnancies were t erminated. In each of three high risk pregnancies which continued, the mother made a ''final hour'' decision not to undergo the scheduled, f irst trimester termination. In our experience, late reversal of a prev ious decision to undergo first trimester pregnancy termination for a g enetic indication is uniquely frequent among couples who have undergon e the prenatal exclusion test for HD.