PRENATAL-DIAGNOSIS BY CHORIONIC VILLUS SAMPLING

Chorionic villus sampling (CVS) retains its great advantage over mid-t rimester amniocentesis by producing early results. Moreover, rapid ana lytical techniques reduce significantly the waiting time between sampl ing and diagnosis, while recombinant DNA technology and human gene map ping progress amplify enormously the spectrum of the indications. The recent inclusion in the prenatal diagnosis package of screening tests based on DNA analysis for the major genetic diseases (i.e. cystic fibr osis, fragile-X mental retardation syndrome) may efficiently contribut e to prevent the genetic disease. The role of CVS in twin pregnancy ha s been investigated and compared to amniocentesis. Although these tech niques are equally safe, CVS should be considered the approach of choi ce for a number of technical advantage and in relation to selective fe tal reduction in discordant twins. Recent reports have substantially c ontributed to the controversy on the hypothetical relationship between limb reduction defects (LRDs) and chorion biopsy. The analysis of LRD s among more than 130 000 CVS reported to WHO CVS-Registry has been un able to find out any relationship between sampling and fetal malformat ions, including LRDs. In conclusion, first trimester CVS should be con sidered the gold standard procedure for prenatal diagnosis of genetic diseases.