[Primary neuraminidase deficiency with prenatal disclosure]

The authors report a case of infantile sialidosis with hydrops fetalis and heart failure. At birth the baby presented a dysmorphic syndrome with histological anomalies. A storage disease with deficiency of neuraminidase activity, sialidosis type II, was confirmed. Amniocentesis with sialic-acid dosage or thin-layed chromatography seems necessary in hydrops fetalis with heart failure of unknown origin.