Language Delay in Patients with CLN2 Disease: Could It Support Earlier Diagnosis?

Neuronal ceroid lipofuscinosis type 2 (CLN2 disease) is a rare pediatric disorder associated with rapid neurodegeneration, and premature death in adolescence. An effective enzyme replacement therapy (cerliponase alfa) has been approved that can reduce this predictable neurological decline. The nonspecific early symptoms of CLN2 disease frequently delay diagnosis and appropriate management. Seizures are generally recognized as the first presenting symptom of CLN2 disease, but emerging data show that language delay may precede this. An improved understanding of language deficits in the earliest stage of CLN2 disease may support the early identification of patients. In this article, CLN2 disease experts examine how language development is affected by CLN2 disease in their clinical practices. The authors' experiences highlighted the timings of first words and first use of sentences, and language stagnation as key features of language deficits in CLN2 disease, and how deficits in language may be an earlier sign of the disease than seizures. Potential challenges in identifying early language deficits include assessing patients with other complex needs, and recognizing that a child's language abilities are not within normal parameters given the variability of language development in young children. CLN2 disease should be considered in children presenting with language delay and/or seizures to facilitate earlier diagnosis and access to treatment that can significantly reduce morbidity.

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The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).

Déclaration de conflit d'intérêts

Writing support was funded by BioMarin Europe Ltd. M.N., P.G., R.G., C.H., B.R., T.R., A.S., I.T., and N.S. received personal fees from BioMarin Europe Ltd for their attendance and contributions at the expert meeting. M.N. has received grants to their institution from BioMarin, REGENXBIO Inc., Orphion Therapeutics, and Polaryx; consulting fees from REGENXBIO Inc.; honoraria from BioMarin; meeting and/or travel support from BioMarin; and payments to their institution from BioMarin and REGENXBIO Inc. P.G. has received consulting fees, contracted research fees, honoraria, and travel expenses from BioMarin Europe Ltd. S.C. has a leadership role in the cognitive neurology and developmental epilepsy neuropsychology study group of the Italian League Against Epilepsy. B.R. has received travel expenses from BioMarin. A.S. has received grants to their institution from BioMarin, REGENXBIO Inc., Orphion Therapeutics, and Polaryx; consulting fees from REGENXBIO Inc.; honoraria from BioMarin; meeting and/or travel support from BioMarin; and payments to their institution from BioMarin and REGENXBIO Inc. I.T. has received travel expenses from BioMarin. N.S. has received travel expenses from BioMarin.BioMarin Europe Ltd played no role in case study collection, writing of the report, or the decision to submit the manuscript.