| Item | Value | Evidence (brief) | Source (paper/URL) | Citation ID |
|---|---|---|---|---|
| Preferred disease name | Neuronal ceroid lipofuscinosis 2 | OpenTargets disease-target association lists disease name as “neuronal ceroid lipofuscinosis 2” | OpenTargets disease association context / https://platform.opentargets.org | (pqac-00000000) |
| MONDO ID | MONDO:0008769 | OpenTargets explicitly reports `MONDO_0008769` for neuronal ceroid lipofuscinosis 2 | OpenTargets disease association context / https://platform.opentargets.org | (pqac-00000000) |
| Orphanet ID | ORPHA:228349 | OpenTargets explicitly reports `Orphanet_228349` for “CLN2 disease” | OpenTargets disease association context / https://platform.opentargets.org | (pqac-00000000) |
| OMIM | OMIM #204500 | Brazilian consensus states CLN2 is also known as “classical late-infantile neuronal ceroid lipofuscinosis or Jansky-Bielschowsky disease (OMIM#204500)” | Sampaio et al., 2023 / https://doi.org/10.1055/s-0043-1761434 | (pqac-00000008) |
| Common synonyms | CLN2 disease; late-infantile Batten disease; TPP1 deficiency; classical late-infantile neuronal ceroid lipofuscinosis; Jansky-Bielschowsky disease | Recent papers and consensus documents use these names interchangeably for the same disorder | Sampaio et al., 2023; Sondhi et al., 2020; Wawrzynski et al., 2024 / https://doi.org/10.1055/s-0043-1761434 ; https://doi.org/10.1126/scitranslmed.abb5413 ; https://doi.org/10.1038/s41433-023-02859-4 | (pqac-00000008, pqac-00000006, pqac-00000015) |
| Disease category | Mendelian lysosomal storage/neurodegenerative disease | Described as an autosomal recessive lysosomal neurodegenerative disorder with lysosomal storage material accumulation | Sondhi et al., 2020 / https://doi.org/10.1126/scitranslmed.abb5413 | (pqac-00000006) |
| Causative gene | TPP1 | OpenTargets shows TPP1 as the single associated target with evidence for CLN2 | OpenTargets disease association context / https://platform.opentargets.org | (pqac-00000000) |
| Protein/enzyme | Tripeptidyl peptidase 1 (TPP1) | Consensus and multiple studies state CLN2 results from deficiency of the soluble lysosomal enzyme TPP1 | Sampaio et al., 2023; Wawrzynski et al., 2024 / https://doi.org/10.1055/s-0043-1761434 ; https://doi.org/10.1038/s41433-023-02859-4 | (pqac-00000008, pqac-00000015) |
| Inheritance | Autosomal recessive | Recent clinical papers describe CLN2 as inherited and caused by biallelic pathogenic variants in TPP1 | Sondhi et al., 2020; Lourenço et al., 2024 / https://doi.org/10.1126/scitranslmed.abb5413 ; https://doi.org/10.1055/s-0044-1786854 | (pqac-00000006, pqac-00000010) |
| Core molecular defect | Loss of TPP1 activity causing lysosomal storage | Reduced/absent TPP1 impairs lysosomal protein degradation, causing storage-material accumulation and neuronal/retinal cell death | Sampaio et al., 2023; Wawrzynski et al., 2024 | (pqac-00000008, pqac-00000015) |
| Key distinguishing onset | Usually age 2–4 years | Multiple recent sources state clinicians should suspect CLN2 in children aged 2–4 years | Sampaio et al., 2023; Wawrzynski et al., 2024; Fietz et al., 2016 | (pqac-00000008, pqac-00000015, pqac-00000001) |
| Key distinguishing early features | Language delay/regression and epilepsy/seizures | Consensus: suspect in “any child, from 2 to 4 years old, with language delay and epilepsy”; classic phenotype includes seizures and language abnormalities | Sampaio et al., 2023; Wibbeler et al., 2021 | (pqac-00000008, pqac-00000004) |
| Additional hallmark features | Ataxia, myoclonus, motor decline/regression, visual loss/retinopathy, premature death | 2024 movement-disorder and ocular studies plus prior clinical studies document stereotyped progression with ataxia/myoclonus, later spasticity/dystonia/hypokinesia, retinal degeneration and early death | Spaull et al., 2024; Gkalapis et al., 2024; Sondhi et al., 2020 | (pqac-00000011, pqac-00000007, pqac-00000006) |
| Typical common variants | c.622C>T (p.Arg208*), c.509-1G>C | Recent ocular/genetic studies identify these as the two variants accounting for most cases in many cohorts | Wawrzynski et al., 2024; Lourenço et al., 2024 | (pqac-00000015, pqac-00000010) |


*Table: This table compiles key disease identifiers, synonyms, inheritance, and core clinical-genetic features for CLN2 disease. It is useful as a normalization and quick-reference artifact for a disease knowledge base entry.*