Children with CLN2 disease produce deficient levels of the enzyme TPP1 (tripeptidyl peptidase 1).^1,3 Without enough of this enzyme, children are unable to dispose of all the wastes normally metabolised in their cell’s lysosomes.^1,3 The wastes accumulate in organs, particularly the brain and retina, contributing to the loss of cognitive, motor and visual function.³

CLN2 disease is autosomal recessive¹, meaning both parents of an affected child have a specific mutation on their TPP1 gene. Parents are usually asymptomatic carriers. If both parents carry the mutation, there is a 25 percent chance that their child will have CLN2 disease.

Signs and symptoms of Late infantile neuronal ceroid lipofuscinosis type 2 (CLN2) disease

Seizures are the most common symptom that brings children to medical attention between ages of 2-4.¹ Often, children can have a history of language delay.¹ Symptoms typically do not present until age 3, at which point children who were previously healthy and developing normally can suddenly experience seizures and language delays.¹

In its most typical presentation, the condition rapidly progresses to dementia,⁴ the loss of the ability to walk and talk, and blindness.¹ By age 6, most affected children will be completely dependent on families and caregivers.³ Tragically, these children typically die between the ages of 8-12.³