Niemann-Pick disease type C laboratory diagnosis algorithm

(a) Significant increase of cholestane-triol, PPCS/lysosphingomyelin-509, bile acid levels, with normal, slightly or markedly elevated lysosphingomyelin concentration. (b) Only the ASMD profile shows a significant elevation of lysosphingomyelin. Other causes of elevated cholestane triol levels include CTX and acid lipase deficiency. (c) Importance of parental study. (d) Positive filipin can show a classical, intermediate, or variant phenotype; some heterozygotes and other diseases may show a slightly abnormal profile. Abbreviations: ASMD: acid sphingomyelinase deficiency; CTX: cerebrotendinous xanthomathosis; NP: Niemann-Pick; VUS: variant of unknown significance. (Modified from: Patterson MC, Clayton P, Gissen P, et al. Recommendations for the detection and diagnosis of Niemann-Pick disease type C. Neurol Clin Pract 2017;7(6):499-511.)