Meyahealth
HomeGeneticsGeneSMPD1 gene
Back to Gene
SMPD1 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

SMPD1 gene

The SMPD1 gene provides instructions for making the enzyme acid sphingomyelinase, which is essential for breaking down fats within cellular compartments called lysosomes.

Normal Function

The SMPD1 gene provides instructions for making an enzyme called acid sphingomyelinase. This enzyme is located in lysosomes, the cell's recycling centers. Acid sphingomyelinase is responsible for converting a lipid called sphingomyelin into another lipid called ceramide. Sphingomyelin also binds to cholesterol and helps form other lipids, which are critical for the normal structure and function of cells and tissues.

Health Conditions Related to Genetic Changes

Niemann-Pick disease

At least 175 mutations in the SMPD1 gene have been found to cause Niemann-Pick disease types A and B. These conditions involve a buildup of fat within cells, leading to lung disease and enlargement of the liver and spleen (hepatosplenomegaly).

  • Type A: This is the more severe form, characterized by significant neurological impairment in early childhood. It is typically caused by mutations that result in a complete loss of enzyme function.
  • Type B: Mutations that allow the enzyme to retain some activity often result in type B.
  • Mechanism: A reduction in enzyme activity causes sphingomyelin to accumulate in cells, leading to cell malfunction and death. Over time, this cell loss impairs the function of the brain, lungs, spleen, and liver.

Other Names for This Gene

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

Frequently Asked Questions

Diagnosis is usually confirmed by measuring acid sphingomyelinase activity in leukocytes or cultured fibroblasts; markedly reduced or absent activity indicates type A, while partially retained activity suggests type B. Molecular genetic testing of the SMPD1 gene is then performed to identify pathogenic mutations.
Infants with type A often present before 6 months of age with failure to thrive, progressive neuro‑developmental delay, hepatosplenomegaly, and a characteristic “cherry‑red” spot in the macula seen on retinal exam. Rapid neurologic decline distinguishes it from the milder type B.
Yes. Carrier testing involves targeted DNA analysis for the known pathogenic SMPD1 variants identified in the affected individual. A simple blood draw or cheek swab provides DNA, and results inform reproductive planning and cascade testing of relatives.
Enzyme replacement therapy (e.g., recombinant human acid sphingomyelinase) is approved for type B and is being studied in type A. Additionally, substrate‑reduction agents and gene‑therapy trials are ongoing; patients should discuss eligibility with a metabolic specialist or refer to clinicaltrials.gov for current studies.===
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

Meyahealth

Ⓒ 2026. All rights reserved by MEYA

About UsTerms & PolicyFAQ