Neuronal Ceroid Lipofuscinosis, PPT1-Related

Gene : PPT1

What is Neuronal Ceroid-Lipofuscinosis?

Neuronal Ceroid-Lipofuscinosis (NCL) is an inherited disorder that affects neural systems. Individuals with this disorder may have gradual loss of previously acquired skills or fail to learn to walk or speak at all. They can also have mild to severe intellectual disability, behavioral problems, vision impairment, seizure and early death. Symptoms can appear starting in infancy, childhood, or later on in adulthood. Individuals with earlier onset often require the use of a wheelchair by late childhood and typically do not survive past their teens. Currently, there is no cure for NCL, but medical surveillance and care may help to improve some symptoms and overall condition of life. Individuals with NCL have been characterized traditionally according to the age of onset and order of appearance of clinical features into infantile, late-infantile, juvenile and adult types. Pathogenic variants in more than 10 genes can cause NCL, and the most common genes include TPP1, PPT1, CLN3, CLN5, CLN6 and CLN8. Pathogenic variants in the PPT1 gene are the major cause of infantile NCL and may cause other types of NCL as well.

How is Neuronal Ceroid-Lipofuscinosis inherited?

NCL caused by pathogenic variants in the PPT1 gene are inherited in an autosomal recessive manner. This type of inheritance requires the presence of two copies of a pathogenic variant in the gene for a person to have the genetic disease. Both parents must be carriers of a pathogenic variant in the gene in order to be at risk to have an affected child. The child must inherit a pathogenic variant from each carrier parent in order to be affected. There is a 1 in 4 chance that a baby will inherit two mutated copies of the gene and be affected when both parents are carriers.

What does it mean to be a carrier?

There are generally no signs or symptoms associated with being a carrier for NCL. However, the risk to have a child affected with NCL is increased. Testing of reproductive partners is recommended for carriers of NCL.

How common is Neuronal Ceroid-Lipofuscinosis?

All types of NCL affect about 1 in 100,000 newborns worldwide. In Finland, NCLs are more common and occur in close to 1 in 12,500 individuals.

Family References and Resources
Clinician References
What is Analyzed?
  • Full gene sequencing
Affected Systems

Brain

Muscle

Eyes

Carrier Rates
Ethnicity
Detection Rate
Carrier Frequency
Finnish > 98% 1 in 72
General Population > 98% 1 in 199

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