Overview

Natural History

CLN2 disease follows a devastatingly rapid course—symptoms and irreversible functional loss compound with age

Timeline of classic CLN2 disease symptom onset and loss of function1-6

Age ranges depicted are averages for the classic late-infantile phenotype. Atypical phenotypes of CLN2 disease can vary in age of onset, rate of progression, and disease manifestation.

Ages 0 to 2

  • Lysosomal accumulation of lipopigments likely begins in the prenatal period, yet children appear to develop normally until the onset of presenting symptoms1
  • The first symptom in a majority of cases is early language delay, as shown in recent clinical findings7
  • In a minority of cases, other developmental delays, motor difficulties, or ataxia may be the first sign4,5
    • Often these can occur together with language delay

Ages 2 to 4

  • Even though language delay may appear earlier, seizures (which occur around age 3) are the symptom that most often leads parents to seek medical attention for CLN2 disease2,8
  • Multiple types of seizures can be observed, including generalized tonic-­clonic, absence, myoclonic, atonic, clonic, and tonic2,4
    • Although seizures are most often unprovoked, febrile seizures may occur4
  • Onset of ataxia often occurs during this stage of the disease5

Ages 4 to 7

  • Symptoms compound with age, and there is a dramatic loss of previously attained skills. During this age range, children with CLN2 disease typically experience1,2,8,9:
    • Language regression
    • Myoclonic seizures, both epileptic and nonepileptic
    • Severe motor function impairment with eventual loss of voluntary movements
    • Movement disorders such as myoclonus, spasticity, dystonia, and chorea
    • Visual deterioration which leads to blindness by age 6 or 7
  • Eventually, there is a complete loss of language and ambulation, and children become wheelchair-dependent, bedridden, and completely reliant on caretakers2

Ages 8 to 12

  • CLN2 disease is characterized by premature death and the majority of children rarely survive past early adolescence1

Blindness is an early symptom in other NCLs, but occurs in the later stage of CLN2 disease.6,9

The CLN2 Disease Clinical Rating Scale is an efficient way to assess disease progression in 2 of 4 major functional areas: motor and language ability

The standardized scoring system can be used to quantitatively assess disease progression at diagnosis and track loss of function over time6

  • Each functional area is scored on a scale of 3 (grossly normal) to 0 (profoundly impaired)6
  • The highest possible score when assessing motor and language function is 67

Functional performance ability is rated as follows6:

In addition to motor and language function assessments, there are also functional domains (each with a 3­-point scale) to assess vision and the frequency of seizures.6

*In some children, normal motor and/or language development was never present. In such cases, the best performance achieved by the child was considered normal. When that performance level became recognizably worse, the child was rated a 2 for slightly abnormal motor function and/or language development.

CLN2 disease is a race against time

The majority of children with CLN2 disease experience a consistent loss of motor and language function, as measured by the CLN2 Disease Clinical Rating Scale7

Longitudinal data from 41 subjects with CLN2 disease in DEM-CHILD registry. CI, confidence interval.

With a rapid rate of progression, 2 years to diagnosis is too long.

  • Average age of first seizure: ~3 years
  • Average age of CLN2 disease diagnosis: ~5 years
  • Average loss per year: ~2 points
  • Median age of death: 10.0 years

References:

  1. Mole SE, Williams RE, and Goebel HH. Correlations between genotype, ultrastructural morphology and clinical phenotype in the neuronal ceroid lipofuscinoses. Neurogenetics. 2005;6:107-126.
  2. Chang M, Cooper JD, Davidson BL, et al. CLN2. In: Mole S, Williams R, and Goebel H, eds. The neuronal ceroid lipofuscinoses (Batten Disease). 2nd ed. Oxford, United Kingdom: Oxford University Press; 2011:80-109.
  3. Schulz A, Kohlschütter A, Mink J, Simonati A, Williams R. NCL diseases – clinical perspectives. Biochimica et Biophysica Acta. 2013;1832:1801–1806.
  4. Pérez-Poyato MS, Marfa MP, Abizanda IF, et al. Late infantile neuronal ceroid lipofuscinosis: mutations in the CLN2 gene and clinical course in Spanish patients. J Child Neurol. 2013;28:470-478.
  5. Worgall S, Sondhi D, Hackett NR, et al. Treatment of late infantile neuronal ceroid lipofuscinosis by CNS administration of a serotype 2 adeno-associated virus expressing CLN2 cDNA. Hum Gene Ther. 2008;19:463-474.
  6. Steinfeld R, Heim P, von Gregory H, et al. Late infantile neuronal ceroid lipofuscinosis: quantitative description of the clinical course in patients with CLN2 mutations. Am J Med Genet. 2002;112:347-354.
  7. Nickel M, Simonati A, Jacoby D, et al. Disease characteristics and progression in patients with late-infantile neuronal ceroid lipofuscinosis type 2 (CLN2) disease: an observational cohort study. Lancet Child Adolesc Health. 2018 Aug;2(8):582-590. doi: 10.1016/S2352-4642(18)30179-2.
  8. Schulz A, Ajayi T, Specchio N, et al. Study of Intraventricular Cerliponase Alfa for CLN2 Disease. N Engl J Med. 2018;378:1898-1907
  9. Malik K, Santucci K, Sremba L, et al. Neuronal Ceroid Lipofuscinoses Overview. 2001 Oct 10 [Updated 2025 May 29]. In: Adam MP, Bick S, Mirzaa GM, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2026.