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PPT1 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

PPT1 gene

The PPT1 gene provides instructions for an enzyme that breaks down fats in cells, which is critical for maintaining healthy nerve cell function.

Normal Function

The PPT1 gene provides instructions for making an enzyme called palmitoyl-protein thioesterase 1. This enzyme is found in structures called lysosomes, which are compartments within cells that break down and recycle different types of molecules. Palmitoyl-protein thioesterase 1 removes certain fats called long-chain fatty acids from specific proteins, typically a fatty acid called palmitate. Removing these fatty acids helps break the proteins down when they are no longer needed. This enzyme is also thought to be involved in a variety of other cell functions, such as the development of synapses, which are the connections between nerve cells where cell-to-cell communication occurs.

Health Conditions Related to Genetic Changes

CLN1 disease

More than 65 mutations in the PPT1 gene have been found to cause CLN1 disease. This condition impairs mental and motor development, causing difficulty with walking, speaking, and intellectual function. In addition, affected children often develop recurrent seizures (epilepsy) and vision loss. Signs and symptoms typically appear by age 18 months but can begin later, sometimes in adulthood.

The PPT1 gene mutations that cause CLN1 disease decrease or eliminate the production or function of palmitoyl-protein thioesterase 1. This leads to a shortage of functional enzyme, which impairs the removal of long-chain fatty acids from certain proteins. These partially broken down fats and proteins accumulate in lysosomes. While this accumulation occurs in cells throughout the body, nerve cells appear to be particularly vulnerable to damage. Early and widespread loss of nerve cells leads to severe signs and symptoms and death in childhood.

In later-onset cases, PPT1 gene mutations result in the production of an enzyme that has a reduced level of normal function rather than a total loss. Because it takes longer for substances to accumulate in lysosomes and cause nerve cell death, the signs and symptoms occur later in life.

Other Names for This Gene

  • ceriod-lipofuscinosis, neuronal 1
  • CLN1
  • INCL
  • palmitoyl-protein hydrolase 1
  • PPT
  • PPT-1
  • PPT1_HUMAN

Genomic Location

The PPT1 gene is found on chromosome 1.

Frequently Asked Questions

definitive diagnosis requires a combination of clinical evaluation, neuroimaging (MRI may show brain atrophy), and a genetic test that identifies pathogenic variants in the PPT1 gene. Enzyme activity assays from skin fibroblasts or blood can also confirm reduced or absent PPT1 activity.
PPT1 mutations are inherited in an autosomal recessive pattern, meaning both parents must carry a mutation for a child to be affected. Carrier testing for both parents can confirm risk, and options such as preimplantation genetic diagnosis or prenatal testing can be discussed with a genetic counselor.
Parents often notice developmental delays such as delayed speech or motor milestones, followed by the onset of seizures or vision problems between 12 and 24 months. A sudden regression in previously acquired skills is also a red flag.
Currently, treatment is mainly supportive: antiepileptic drugs to control seizures, vision aids, and physical therapy to maintain mobility. Experimental therapies such as gene therapy trials and enzyme replacement strategies are under investigation and may become options in the near future.
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.

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