Niemann–Pick disease (NPD) is an autosomal recessive disease caused by reduced expression of the enzyme acid sphingomyelinase (ASM), encoded by the sphingomyelin phosphodiesterase 1 (SMPD1) gene, resulting in lysosomal accumulation of sphingomyelin in [1, 2] the brain causing irreversible neurological damage. The gene discussed is SMPD1; the disease is Niemann-Pick disease.