Incidence and timing of diagnosis of neuronal ceroid lipofuscinosis type 2 (CLN2): A nationwide study using the French hospital discharge database

Eur J Paediatr Neurol. 2025 Dec 3;60:44-49. doi: 10.1016/j.ejpn.2025.12.001. Online ahead of print.

ABSTRACT

BACKGROUND: Neuronal ceroid lipofuscinoses (NCLs) are rare, progressive lysosomal neurodegenerative disorders. Among late-infantile onset forms (after 18 months of age), type 2 (CLN2 disease) is the most frequent. This study assessed the incidence and disease burden at diagnosis of CLN2 disease in France.

METHODS: This was a nationwide, population-based, retrospective study including all patients identified with CLN2 disease in the French Hospital Discharge Database (Programme de Médicalisation des Systèmes d'Information, PMSI) from January 2015 to December 2023.

RESULTS: After a 2-year washout period to exclude prevalent patients, 51 children were considered to have been diagnosed with CLN2 disease over 7 years (2017-2023). Based on national birth statistics, this corresponds to an incidence of 0.99 cases of CLN2 disease per 100,000 live births. Median age at diagnosis was 5 years (interquartile range, 3-8), with a mean diagnostic delay of 19.1 ± 19.8 months from the first coded symptoms. Epilepsy (90.2 %) and intellectual disability (86.3 %) were the most frequently coded comorbidities. Of the 51 children, 84.3 % were hospitalized via emergency care, and 45.1 % required intensive care. Overall, 13 deaths (25.5 %) were reported, with median age at death of 9 years.

CONCLUSIONS: This is the first nationwide epidemiological assessment of CLN2 disease in France. The results demonstrate substantial diagnostic delays and disease burden, underscoring the need for earlier diagnosis and referral to expert centers to optimize care and offer genetic counseling to parents before conceiving subsequent offspring.

PMID:41354011 | DOI:10.1016/j.ejpn.2025.12.001