Chemical and biochemical studies in human fetuses affected with Niemann-Pick disease type A.

Chemical and biochemical studies were performed on two unrelated fetuses affected with Niemann-Pick disease type A, following abortion at about the 19th week of gestation. Abortion was performed as a consequence of previous findings, in amniotic fluid cell cultures, that sphingomyelinase activity was completely absent. Phospholipid analyses of various organs of the fetuses revealed an excess of sphingomyelin in all viscera as compared to control nonaffected fetuses. Spleen and liver were the organs mostly affected. Interestingly enough considerable accumulation of sphingomyelin was found in the placenta. The brain was the only organ in which sphingomyelin storage could not be proved. In addition to sphingomyelin a slight accumulation of cholesterol was noticed. Deficiency of sphingomyelinase activity measured at pH 5.0 was the general characteristics of the affected tissues. It could be concluded that the accumulation of sphingomyelin in various organs throughout the body of fetuses affected with Niemann-Pick disease, was suggestive of the essential role of the enzyme sphingomyelinase and its biochemical maturation, even during the early stages of gestation.