First trimester prenatal diagnosis of metabolic diseases: a survey in countries from the European community.

This paper presents the collected data concerning First Trimester Prenatal Diagnosis of Metabolic Diseases performed in different countries of the European Community by enzymatic methods using chorionic villi. In all, 258 diagnoses were made for 38 different metabolic diseases and 56 (22 per cent) affected fetuses have been detected. Several difficulties were encountered with regard to chorionic villus material or enzyme expression in this tissue. We stress the conditions necessary for avoiding errors in diagnosis.