Further description of the phenotypic spectrum of neuronal ceroid lipofuscinosis type 11.

Purpose: Ceroid lipofuscinosis type 11 (CLN11) is a very rare disease, being reported in only 13 unrelated families so far. Further reports are necessary to comprehend the clinical phenotype of this condition. This article aims to report 9 additional cases of CLN11 from 9 unrelated Latin American families presenting with relatively slow disease progression.

Methods: This was a retrospective observational study including patients with CLN11. Patients were identified through an active search for granulin precursor gene (GRN) pathogenic variants across the entire database of next-generation sequencing of a commercial laboratory and by contacting attending physicians to check for clinical and radiologic findings compatible with a neuronal ceroid lipofuscinosis phenotype.

Results: Nine CLN11 patients from unrelated families were evaluated. Age of onset varied between 3 to 17 years. The most common findings were visual impairment, cerebellar ataxia, seizures, myoclonus, and cognitive decline. One patient had a previously unreported finding of cervical, perioral, and tongue myoclonus. Most of the patients were able to walk unassisted after an average of 14.2 years (SD 4.76 y) from disease onset.

Conclusion: We describe 9 new cases of a very rare type of neuronal ceroid lipofuscinosis (CLN11) from Latin America with a recurrent p.(Gln257ProfsTer27) and a novel p.(Cys83Ter) nonsense variant. Our findings suggest that a slowly progressive neuronal ceroid lipofuscinosis might be a clue for the diagnosis of CLN11.