Fetal GM1-gangliosidosis: morphological and biochemical studies.

A 23-week fetus with GM1-gangliosidosis type 1 was studied morphologically and biochemically. The GM1-ganglioside content in the brain was approximately twice that of a control. A GM1-ganglioside comprised about 25% of the total ganglioside NANA (N-acetyl-neuraminic acid), whereas in control fetus brain the proportion was 14.3%. The storage of GM1-ganglioside in fetal GM1-ganglioside brain was confirmed by a thin-layer chromatogram immunostained with anti-GM1-ganglioside antibody. The accumulation of GM1-ganglioside in visceral organs (liver, spleen and kidney) was not detected with biochemical and immunochemical methods. However, in hepatocytes, Kupffer cells, renal tubular cells and spleen cells from the affected fetus, there were many vacuoles which could contain oligosaccharides as storage materials. These data suggest that pathochemical changes in the brain and visceral organs of an affected fetus are already evident in the second trimester of the pregnancy. Tissue specific accumulation of glycolipids or oligosaccharides in fetal GM1-gangliosidosis suggests that the biosynthesis or degradation of these compounds occurs at different periods.