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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed January 2015

What is the official name of the SMPD1 gene?

The official name of this gene is “sphingomyelin phosphodiesterase 1, acid lysosomal.”

SMPD1 is the gene's official symbol. The SMPD1 gene is also known by other names, listed below.

What is the normal function of the SMPD1 gene?

The SMPD1 gene provides instructions for making an enzyme called acid sphingomyelinase. This enzyme is found in lysosomes, which are small compartments in the cell that digest and recycle molecules. Acid sphingomyelinase is responsible for the conversion of a fat (lipid) called sphingomyelin into another type of lipid called ceramide. Sphingomyelin also binds (attaches) to a fat called cholesterol and helps to form other lipids that play roles in various cell processes. The formations of these lipids is critical for the normal structure and function of cells and tissues.

How are changes in the SMPD1 gene related to health conditions?

Niemann-Pick disease - caused by mutations in the SMPD1 gene

At least 175 mutations in the SMPD1 gene have been found to cause Niemann-Pick disease types A and B. These types of Niemann-Pick disease are characterized by a buildup of fat within cells that leads to lung disease and enlargement of the liver and spleen (hepatosplenomegaly). Type A is more severe and is characterized by severe neurological impairment in early childhood.

SMPD1 gene mutations that cause complete loss of enzyme function tend to cause Niemann-Pick disease type A. In the Ashkenazi (eastern and central European) Jewish population, three mutations are responsible for about 90 percent of all Niemann-Pick disease type A cases. Mutations that lead to the production of an enzyme that retains some activity often cause Niemann-Pick disease type B. A reduction in enzyme activity within cells allows sphingomyelin to accumulate in cells. The accumulation of this lipid causes cells to malfunction and eventually die. Over time, cell loss impairs function of tissues and organs including the brain, lungs, spleen, and liver in people with Niemann-Pick disease types A and B.

Where is the SMPD1 gene located?

Cytogenetic Location: 11p15.4-p15.1

Molecular Location on chromosome 11: base pairs 6,390,301 to 6,394,998

The SMPD1 gene is located on the short (p) arm of chromosome 11 between positions 15.4 and 15.1.

The SMPD1 gene is located on the short (p) arm of chromosome 11 between positions 15.4 and 15.1.

More precisely, the SMPD1 gene is located from base pair 6,390,301 to base pair 6,394,998 on chromosome 11.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about SMPD1?

You and your healthcare professional may find the following resources about SMPD1 helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the SMPD1 gene or gene products?

  • acid sphingomyelinase
  • ASM
  • sphingomyelin phosphodiesterase 1, acid lysosomal (acid sphingomyelinase)

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding SMPD1?

cell ; cholesterol ; enzyme ; gene ; hepatosplenomegaly ; lipid ; neurological ; population

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


  • Hollak CE, de Sonnaville ES, Cassiman D, Linthorst GE, Groener JE, Morava E, Wevers RA, Mannens M, Aerts JM, Meersseman W, Akkerman E, Niezen-Koning KE, Mulder MF, Visser G, Wijburg FA, Lefeber D, Poorthuis BJ. Acid sphingomyelinase (Asm) deficiency patients in The Netherlands and Belgium: disease spectrum and natural course in attenuated patients. Mol Genet Metab. 2012 Nov;107(3):526-33. doi: 10.1016/j.ymgme.2012.06.015. Epub 2012 Jun 30. (
  • Irun P, Mallén M, Dominguez C, Rodriguez-Sureda V, Alvarez-Sala LA, Arslan N, Bermejo N, Guerrero C, Perez de Soto I, Villalón L, Giraldo P, Pocovi M. Identification of seven novel SMPD1 mutations causing Niemann-Pick disease types A and B. Clin Genet. 2013 Oct;84(4):356-61. doi: 10.1111/cge.12076. Epub 2013 Jan 4. (
  • NCBI Gene (
  • Schuchman EH. The pathogenesis and treatment of acid sphingomyelinase-deficient Niemann-Pick disease. J Inherit Metab Dis. 2007 Oct;30(5):654-63. Epub 2007 Jul 12. Review. (
  • Simonaro CM, Desnick RJ, McGovern MM, Wasserstein MP, Schuchman EH. The demographics and distribution of type B Niemann-Pick disease: novel mutations lead to new genotype/phenotype correlations. Am J Hum Genet. 2002 Dec;71(6):1413-9. Epub 2002 Oct 4. (
  • Wasserstein MP, Aron A, Brodie SE, Simonaro C, Desnick RJ, McGovern MM. Acid sphingomyelinase deficiency: prevalence and characterization of an intermediate phenotype of Niemann-Pick disease. J Pediatr. 2006 Oct;149(4):554-9. (
  • Wasserstein MP, Desnick RJ, Schuchman EH, Hossain S, Wallenstein S, Lamm C, McGovern MM. The natural history of type B Niemann-Pick disease: results from a 10-year longitudinal study. Pediatrics. 2004 Dec;114(6):e672-7. Epub 2004 Nov 15. (


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? ( in the Handbook.

Reviewed: January 2015
Published: November 23, 2015