Prenatal diagnosis of galactosaemia in six pregnancies -- possible complications with rare alleles of the galactose 1-phosphate uridyl transferase locus.

We describe our experience in prenatal diagnosis of six foetuses at risk for galactosaemia. In one family the parents were both shown to be double heterozygotes at the galactose 1-phosphate uridyl transferase (Gal-PUT) locus, the mother having a Duarte Suppl.Los Angeles and the father a Duarte Suppl.galactosaemia genotype. The foetus (and an older brother previously thought to have classical galactosaemia) was also a Duarte/galactosaemia double heterozygote. In the other five families, the parents and three foetuses were heterozygous carriers of the galactosaemia gene, one of the foetuses had galactosaemia, and one was homozygous for the normal gene. It is concluded that by a combination of family studies and assay of cultured amniotic cell Gal-PUT, accurate prediction of the foetal Gal-PUT genotype is now possible.