Acid sphingomyelinase (Asm) deficiency patients in The Netherlands and Belgium: Disease spectrum and natural course in attenuated patients

► 25 patients with ASM deficiency are identified in the Netherlands and Belgium. ► Prominent symptoms are hepatosplenomegaly, thrombocytopenia and pulmonary disease. ► In 4 NPD-B patients, disease parameters remained stable up to 6 years. ► Bone marrow fat fractions are decreased. ► Extensive pulmonary disease can be present in cases with mild visceromegaly.