1.Historical aspects of Niemann-Pick disease122.Biochemistry of Niemann-Pick disease182.1.Introduction and definitions182.2.Missing or pathological products of "Niemann-Pick genes"192.3.Biochemical foundations of diagnosing Niemann-Pick diseases 192.3.1.Niemann-Pick disease, SMPD1-associated192.3.2.Niemann-Pick disease, transport protein deficiency-associated (NPC1, NPC2)192.3.3.Chitotriosidase activity in plasma202.3.4.Determination of oxysterols202.3.5.Determination of lyso-sphingomyelin-509 (lyso-SM-509)212.3.6.Determination of bile acids212.4.Biochemistry of Niemann-Pick diseases that is pathogenetically relevant or suspected to be significant212.4.1.Niemann-Pick disease, SMPD1-associated212.4.2.Niemann-Pick disease, transport protein deficiency-associated (NPC1, NPC2) in general222.4.3.Niemann-Pick disease, transport protein deficiency-associated (NPC1, NPC2), central nervous system242.5.Animal models252.5.1.Niemann-Pick disease, SMPD1-associated252.5.2.Niemann-Pick disease, transport protein deficiency-associated (NPC1, NPC2)252.6.Therapeutic concepts for the possible influence of pathogenetically significant metabolic changes262.6.1.Niemann-Pick disease, SMPD1-associated262.6.2.Niemann-Pick disease, transport protein deficiency-associated (NPC1)263.Genetics of Niemann-Pick disease343.1.Niemann-Pick disease type A/B (NPA/B) [MIM: 257200/607616]343.1.1.SMPD1 gene and ASM protein [HGNC Gene-ID: 11120]343.1.2.SMPD1 variants343.2.Niemann-Pick disease type C (NPC) [MIM: 257220/607625]353.2.1.NPC1 gene and protein [HGNC Gene-ID: 7897]363.2.2.NPC1 variants373.2.3.NPC2 gene and protein [HGNC Gene-ID: 14537]383.2.4.NPC2 variants383.3.Challenges of genetic testing in Niemann-Pick disease and outlook383.4.Genetic databases for Niemann-Pick diseases394.Diagnosis of Niemann-Pick disease type C (NPC) 444.1.Recommendations for differential diagnosis and initial diagnosis444.2.Clinical diagnosis and key findings in NPC464.2.1.Neuropsychological diagnosis and key findings464.2.2.Laboratory diagnostics and biomarkers474.3.Significance of genetic testing in NPC504.3.[...]-generation sequencing (NGS) and gene panels524.3.2.Differentiation from acid sphingomyelinase deficiency (ASMD)524.4.Differential diagnosis of similar lysosomal diseases545.Clinical manifestation585.1.Niemann-Pick disease type A and type B585.2.Niemann-Pick type C disease625.2.1.Perinatal type635.2.2.Infantile type645.2.[...]-infantile type645.2.4.Juvenile classic type675.2.[...] type705.2.6.Psychiatric manifestations in Niemann-Pick type C disease716.Management and treatment of Niemann-Pick diseases806.1.Management and treatment of Niemann-Pick type A/B disease806.1.1.Supportive care806.1.2.Causal therapeutic approaches816.1.3.Future therapy options826.2.Management and treatment of Niemann-Pick type C disease836.2.1.Miglustat846.2.[...] marrow and liver transplantations856.2.3.Treatment of extrapyramidal symptoms, spasticity, cataplexy and epilepsy856.2.4.Substances in preclinical and experimental studies86Index87