Any disease marked by a defective metabolism of sphingolipids. These genetically determined errors of metabolism include Sandhoffs disease, Fabry’s disease, Tay-Sachs disease, Kufs’ disease, Gaucher’s disease, Krabbe’s leukodystrophy, Niemann-Pick disease, Batten disease, and Spielmeyer-Vogt disease. They are marked by neurological deterioration, usually beginning a few months after birth and eventually leading to death except in the adult form of Gaucher’s disease. These diseases can be detected by examining fluid obtained by amniocentesis.