[Hydrops fetalis as an indication for a systematic investigation into the presence of lysosomal storage diseases].

As a result of the decreased incidence of immunological hydrops fetalis and increased insight, the role of inborn errors of metabolism (IEM) as a cause of hydrops fetalis has acquired increased significance. This growing awareness of the manifestation of IEM in pregnancy has revealed that some 20 of these disorders may cause hydrops fetalis, accounting for a few percent of all cases. These IEM are, for the most part, lysosomal storage diseases. We recommend that standard metabolites and enzymes reflecting lysosomal storage diseases be measured in the amniotic fluid and the amniocytes already withdrawn for karyotyping. The value of the diagnosis of lysosomal storage diseases lies in the opportunity for risk evaluation, genetic counselling and targeted prenatal diagnostics in case of subsequent pregnancies. Obtaining insight into the possible therapestic interventions during the pregnancy in which the hydrops is observed is not a goal of this protocol since the necessary investigations are too time-consuming.