Adult sphingomyelinase deficiency: report of 2 patients who initially presented with psychiatric disorders.

We studied 2 unrelated adult patients under neuroleptic treatment who met all phenotypic and biochemical criteria for Niemann-Pick disease type B. In addition, they had chronic psychiatric disorders and low blood levels of HDL cholesterol. The marked and persistent deficiency of acid sphingomyelinase and the disturbance of sphingomyelin metabolism in skin fibroblast subcultures ruled out a pure drug-induced lipidosis. The association of Niemann-Pick disease type B with psychiatric disorders and with low levels of HDL cholesterol could be a chance association of 2 diseases, a new phenotype of Niemann-Pick type B, or the revelation by the neuroleptic treatment of a subclinical inborn sphingomyelinase deficiency.