Thelansis

  CLN2 disease is a lysosomal storage disorder in the neuronal ceroid lipofuscinosis (NCL) family caused by deficiency of the lysosomal enzyme tripeptidyl peptidase 1 (TPP1), resulting from mutations in the TPP1 gene. CLN2 disease typically presents with seizures between the ages of 2 and 4 years, with language delays increasingly reported as a preceding symptom. Other symptoms reported at presentation included developmental delay, motor dysfunction, ataxia, behavioral abnormalities, and dementia. In later stages, it is characterized by a progressive decline of visual and cognitive functions, and it is usually fatal in early adolescence. Diagnostic delays of over 2 years are not uncommon for patients with CLN2 disease, and these coincide with the period during which rapid disease progression begins. Aside from limited awareness of CLN2 disease, several other factors may delay its diagnosis. Early symptoms such as seizures and language delays are also associated with many differen...