Prenatal diagnosis (PD) startcd in the fifties when variotls groups indicated the possibility of
prenatal sex determination in amniotic fluid (AF) cells (SeIT et al., 1955; Fuchs and Riis,
1956; Dewhurst, 1956). After the first succesful attempts at AF cell cultivation and
karyotyping by SteeIe and Breg (1966) and T1tiede et al. (1966), the first small series of
prcnatal chromosomc analyses were presented (Jacobsoll aud Barter, 1967), aud the ficst
chromosome aberrations in cultured AF cells were detected (Valenti et al., 1969). AF cells
could also be used for prenatal detcction of inham errors of metabolism (NadIer, 1968). Our
eentre made an important international contribution towards experienee with a large number
of biochemical assays, and the devclopment of ultramicrochemical techlliques penllitting a
rapid PD (Galjaard, 1972; Niermeijer, 1975; Galjaard, 1976a, 1979, 1980; Galjaard et al.,
1977; K1eijer, 1990). AtlOther important contribution to PD was the finding by Broek and
Sutcliffe (1972), that the alpha-fetoprotein level in AF is increascd when the fetus has an open
neural tube defect
