Prenatal diagnosis of enzyme defects--an update.

The trends in prenatal diagnosis of enzyme defects predicted last year,' namely an increase in diagnosis in the first trimester by chorionic villus sampling and early amniocentesis and greater exploitation of DNA analysis and the diagnosis of genetic errors in preimplantation embryos, have been fulfilled. These developments were also reflected in the papers presented at the 5th International Congress on Early Fetal Diagnosis, held in Prague in July 1990.