Acid Sphingomyelinase Deficiency (ASMD, OMIM 607616), also known as Niemann‐Pick disease types A and B, is a rare lysosomal storage disorder caused by two bi‐allelic mutations in the SMPD1 gene resulting in a deficiency of acid sphingomyelinase (EC 3.1.4.12) [1, 2]. The gene discussed is SMPD1; the disease is Niemann-Pick disease type A.