Neuronal Ceroid Lipofuscinosis Type Research Articles

The neuronal ceroid lipofuscinosis type 2 – associated variants: An analysis of alterations in the TPP1 gene and genotype–phenotype correlation in Ukraine

AbstractThe neuronal ceroid lipofuscinosis type 2 (CLN2) is a heterogeneous group of neurodegenerative lysosomal storage disorders caused by autosomal recessive inheritance of two pathogenic variants in trans in the TPP1 gene. Classical late‐infantile CLN2 disease has a very well‐defined natural history. However, a small number of patients with TPP1 enzyme deficiency present a later onset or protracted disease course within this group there are phenotypic variants. Our work aimed to identify pathological variants in the TPP1 gene that conditioned the development of CLN2 disease in Ukrainian patients, to compare these variants with those found in patients from other European and non‐European regions, and to make genotype–phenotype associations for this disease. The phenotypes and genotypes of the 48 CLN2‐affected individuals belonging to 43 families were profiled through clinical data collection, enzyme analysis, and genotyping. In most patients, genotype and phenotype correlation are in keeping with the data of previous studies. The clinical signs of the disease in patients with new, previously undescribed variants, allowed us to augment existing data about genotype–phenotype correlations for CLN2 disease. The combination of genotype and clinical form of the disease demonstrated that predicting the type and clinical course of the disease based on genotype is very complicated. The data we obtained supplements existing information on genotype–phenotypic correlations in this rare disease, which, in turn, lays the foundation for a personalized approach to the management of this disease.

A needle in a haystack? The impact of a targeted epilepsy gene panel in the identification of a treatable but rapidly progressive metabolic epilepsy: CLN2 disease.

Neuronal ceroid lipofuscinoses (NCL) are a group of autosomal recessive, inherited, lysosomal, and neurodegenerative diseases that causes progressive dementia, seizures, movement disorders, language delay/regression, progressive visual failure, and early death. Neuronal ceroid lipofuscinosis type 2 (CLN2), caused by biallelic pathogenic variants of the TPP1 gene, is the only NCL with an approved targeted therapy. The laboratory diagnosis of CLN2 is established through highly specific tests, leading to diagnostic delays and eventually hampering the provision of specific treatment for patients with CLN2. Epilepsy is a common and clinically-identifiable feature among NCLs, and seizure onset is the main driver for families to seek medical care. To evaluate the results of the Latin America Epilepsy and Genetics Program, an epilepsy gene panel, as a comprehensive tool for the investigation of CLN2 among other genetic causes of epilepsy. A total of 1,284 patients with epilepsy without a specific cause who had at least 1 symptom associated with CLN2 were screened for variants in 160 genes associated with epilepsy or metabolic disorders presenting with epilepsy through an epilepsy gene panel. Variants of the TPP1 gene were identified in 25 individuals (1.9%), 21 of them with 2 variants. The 2 most frequently reported variants were p.Arg208* and p.Asp276Val, and 2 novel variants were detected in the present study: p.Leu308Pro and c.89 + 3G > C Intron 2. The results suggest that these genetic panels can be very useful tools to confirm or exclude CLN2 diagnosis and, if confirmed, provide disease-specific treatment for the patients.

Cathepsin D inhibition during neuronal differentiation selectively affects individual proteins instead of overall protein turnover

Cathepsin D (CTSD) is a lysosomal aspartic protease and its inherited deficiency causes a severe pediatric neurodegenerative disease called neuronal ceroid lipofuscinosis (NCL) type 10. The lysosomal dysfunction in the affected patients leads to accumulation of undigested lysosomal cargo especially in none-dividing cells, such as neurons, resulting in death shortly after birth. To explore which proteins are mainly affected by the lysosomal dysfunction due to CTSD deficiency, Lund human mesencephalic (LUHMES) cells, capable of inducible dopaminergic neuronal differentiation, were treated with Pepstatin A. This inhibitor of “acidic” aspartic proteases caused accumulation of acidic intracellular vesicles in differentiating LUHMES cells. Pulse-chase experiments involving stable isotope labelling with amino acids in cell culture (SILAC) with subsequent mass-spectrometric protein identification and quantification were performed. By this approach, we studied the degradation and synthesis rates of 695 and 680 proteins during early and late neuronal LUHMES differentiation, respectively. Interestingly, lysosomal bulk proteolysis was not altered upon Pepstatin A treatment. Instead, the protease inhibitor selectively changed the turnover of individual proteins. Especially proteins belonging to the mitochondrial energy supply system were differentially degraded during early and late neuronal differentiation indicating a high energy demand as well as stress level in LUHMES cells treated with Pepstatin A.

Intravitreal enzyme replacement therapy to prevent retinal disease progression in children with neuronal ceroid lipofuscinosis type 2 (CLN2): Unilateral injection results

Intravitreal enzyme replacement therapy to prevent retinal disease progression in children with neuronal ceroid lipofuscinosis type 2 (CLN2): Unilateral injection results

Interim results from the first-in-human intracisternal dosing of RGX-181 investigational AAV9 gene therapy in a child with late infantile neuronal ceroid lipofuscinosis type 2 (CLN2)

Interim results from the first-in-human intracisternal dosing of RGX-181 investigational AAV9 gene therapy in a child with late infantile neuronal ceroid lipofuscinosis type 2 (CLN2)

Safety and efficacy of cerliponase alfa in children with neuronal ceroid lipofuscinosis type 2 (CLN2 disease): an open-label extension study

Safety and efficacy of cerliponase alfa in children with neuronal ceroid lipofuscinosis type 2 (CLN2 disease): an open-label extension study

2438. Positive Cerebrospinal Fluid Cultures from Intraventricular Reservoirs for CLN2 Patients: One Institution's Experience

Abstract Background Enzyme replacement therapy (ERT) with cerliponase alfa (Brineura) has been shown to slow progression of milestone deterioration in Neuronal Ceroid Lipofuscinosis Type 2 (CLN2), an inherited neurodegenerative lysosomal storage disorder. Brineura must be administered intraventricularly every 2 weeks, necessitating the placement of ventricular reservoirs and requiring frequent access. Traditionally, positive cerebrospinal fluid (CSF) cultures are managed with device replacement and antibiotic treatment. We sought to establish which circumstances might allow for careful observation without device removal. In this study, we report our single-institution experience with clinical outcomes of positive CSF cultures in 16 CLN2 patients over 6 years. Methods We retrospectively reviewed a cohort of 16 patients with CLN2 disease who had ventricular reservoirs placed for ERT administration. At each ERT infusion, CSF was collected by sterile technique and cultured by both thioglycolate broth and agar plate. Epidemiologic and microbiologic data, symptomatology, total antibiotic days, removal and replacement of ventricular reservoir, hospital length of stay, and mortality were analyzed for each patient. Results In our cohort, 11 of 16 patients (69%) had at least one positive CSF culture (Fig 1). Of the 11 with positive cultures, only 3 had their device removed and replaced for a positive culture with concurrent antibiotic treatment at our center, and 2 patients subsequently have been treated with prophylactic antibiotics at infusions (Fig 2). Out of 1401 total CSF cultures, 64 (4.56%) were positive. The most common organism grown was Cutibacterium acnes, which typically grew in only broth culture (82%), suggesting low bacterial burden (Fig 3). The other 7 patients with positive cultures remained asymptomatic with no intervention required. Conclusion At our institution, we have found that in asymptomatic patients with frequently accessed ventricular reservoirs, positive CSF culture with low virulence skin flora was common, and rarely required intervention. This strategy reduced the risks of invasive surgery, prolonged antibiotic courses, and missed infusions. In the future, routine screening cultures in asymptomatic patients can be avoided. Disclosures Raymond Wang, MD, Biomarin Pharmaceutical: Advisor/Consultant|Biomarin Pharmaceutical: Grant/Research Support|Biomarin Pharmaceutical: equity interest Antonio C. Arrieta, MD, FIDSA, FPIDS, Astellas Pharma Global Development, Inc.: Advisor/Consultant|Astellas Pharma Global Development, Inc.: Grant/Research Support|Astellas Pharma Global Development, Inc.: Honoraria|Cumberland Pharmaceutical: Grant/Research Support|IDbyDNA: Advisor/Consultant|IDbyDNA: Grant/Research Support|Melinta: Grant/Research Support|Merck: Advisor/Consultant|Merck: Grant/Research Support|Nabriva: Grant/Research Support|Paratek Pharmaceuticals: Grant/Research Support|Pfizer, Inc: Advisor/Consultant|Pfizer, Inc: Grant/Research Support|Roche/Genentech: Grant/Research Support|The Medicine Company: Grant/Research Support

CLN2 disease resulting from a novel homozygous deep intronic splice variant in TPP1 discovered using long-read sequencing

Neuronal ceroid lipofuscinosis type 2 (CLN2) is an autosomal recessive neurodegenerative disorder with enzyme replacement therapy available. We present two siblings with a clinical diagnosis of CLN2 disease, but no identifiable TPP1 variants after standard clinical testing. Long-read sequencing identified a homozygous deep intronic variant predicted to affect splicing, confirmed by clinical DNA and RNA sequencing. This case demonstrates how traditional laboratory assays can complement emerging molecular technologies to provide a precise molecular diagnosis.

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.

Economic analysis of cerliponase alfa for treatment of late-infantile neuronal ceroid lipofuscinosis type 2 (CLN2)

ABSTRACT Background Cerliponase alfa is an orphan drug approved for the treatment of late-infantile neuronal ceroid lipofuscinosis type 2 (CLN2). Aim Our goal was to assess the cost-effectiveness of cerliponase alfa in patients with CLN2 in the socioeconomic context of the Republic of Serbia in contrast to symptomatic therapy. Method For this study, a forty-year horizon and the perspective of the Serbian Republic Health Insurance Fund were used. Quality-adjusted life years gained with cerliponase alfa and comparator, as well as direct treatment costs, were the study’s key outcomes. The creation and simulation of a discrete-event simulation model served as the basis for the investigation. Monte Carlo microsimulation was performed on a sample of 1000 virtual patients. Results When compared to symptomatic therapy, cerliponase alfa treatment was not cost-effective and was linked to negative net monetary benefit regardless of when the illness signs started. Conclusion Cerliponase alfa is not more economical than symptomatic therapy for the treatment of CLN2 when using typical pharmacoeconomic analysis. Cerliponase alfa has been shown to be effective but more has to be done to make it accessible to all CLN2 patients.

Magnetic resonance brain volumetry biomarkers of CLN2 Batten disease identified with miniswine model

Late-infantile neuronal ceroid lipofuscinosis type 2 (CLN2) disease (Batten disease) is a rare pediatric disease, with symptom development leading to clinical diagnosis. Early diagnosis and effective tracking of disease progression are required for treatment. We hypothesize that brain volumetry is valuable in identifying CLN2 disease at an early stage and tracking disease progression in a genetically modified miniswine model. CLN2R208X/R208X miniswine and wild type controls were evaluated at 12- and 17-months of age, correlating to early and late stages of disease progression. Magnetic resonance imaging (MRI) T1- and T2-weighted data were acquired. Total intercranial, gray matter, cerebrospinal fluid, white matter, caudate, putamen, and ventricle volumes were calculated and expressed as proportions of the intracranial volume. The brain regions were compared between timepoints and cohorts using Gardner-Altman plots, mean differences, and confidence intervals. At an early stage of disease, the total intracranial volume (− 9.06 cm3), gray matter (− 4.37% 95 CI − 7.41; − 1.83), caudate (− 0.16%, 95 CI − 0.24; − 0.08) and putamen (− 0.11% 95 CI − 0.23; − 0.02) were all notably smaller in CLN2R208X/R208X miniswines versus WT, while cerebrospinal fluid was larger (+ 3.42%, 95 CI 2.54; 6.18). As the disease progressed to a later stage, the difference between the gray matter (− 8.27%, 95 CI − 10.1; − 5.56) and cerebrospinal fluid (+ 6.88%, 95 CI 4.31; 8.51) continued to become more pronounced, while others remained stable. MRI brain volumetry in this miniswine model of CLN2 disease is sensitive to early disease detection and longitudinal change monitoring, providing a valuable tool for pre-clinical treatment development and evaluation.

Cynomolgus macaque model of neuronal ceroid lipofuscinosis type 2 disease

Neuronal ceroid lipofuscinoses (NCLs) are autosomal-recessive fatal neurodegenerative diseases that occur in children and young adults, with symptoms including ataxia, seizures and visual impairment. We report the discovery of cynomolgus macaques carrying the CLN2/TPP1 variant and our analysis of whether the macaques could be a new non-human primate model for NCL type 2 (CLN2) disease. Three cynomolgus macaques presented progressive neuronal clinical symptoms such as limb tremors and gait disturbance after about 2 years of age. Morphological analyses using brain MRI at the endpoint of approximately 3 years of age revealed marked cerebellar and cerebral atrophy of the gray matter, with sulcus dilation, gyrus thinning, and ventricular enlargement. Histopathological analyses of three affected macaques revealed severe neuronal loss and degeneration in the cerebellar and cerebral cortices, accompanied by glial activation and/or changes in axonal morphology. Neurons observed throughout the central nervous system contained autofluorescent cytoplasmic pigments, which were identified as ceroid-lipofuscin based on staining properties, and the cerebral cortex examined by transmission electron microscopy had curvilinear profiles, the typical ultrastructural pattern of CLN2. These findings are commonly observed in all forms of NCL. DNA sequencing analysis identified a homozygous single-base deletion (c.42delC) of the CLN2/TPP1 gene, resulting in a frameshifted premature stop codon. Immunohistochemical analysis showed that tissue from the affected macaques lacked a detectable signal against TPP1, the product of the CLN2/TPP1 gene. Analysis for transmission of the CLN2/TPP1 mutated gene revealed that 47 (49.5%) and 48 (50.5%) of the 95 individuals genotyped in the CLN2-affected macaque family were heterozygous carriers and homozygous wild-type individuals, respectively. Thus, we identified cynomolgus macaques as a non-human primate model of CLN2 disease. The CLN2 macaques reported here could become a useful resource for research and the development of drugs and methods for treating CLN2 disease, which involves severe symptoms in humans.

The diagnostic challenges presented in a patient with neuronal ceroid lipofuscinosis type 2

Neuronal ceroid lipofuscinosis type 2 (NCL2) is a severe, continuously progressive hereditary metabolic disease for which there is an effective enzyme replacement therapy.Purpose. To study the opinions of specialists (pediatric neurologists, neurologists-epileptologists, geneticists) about the obstacles to the early diagnosis of neuronal ceroid lipofuscinosis type 2 in patients.Material and methods. The study was conducted by the method of in-depth interviews. 25 physicians dealing with NCL2 pts took part in the interview.Results. From 2000 to 2021, 45 patients with NCL2 were identified in the Russian Federation. Data on the course of the disease were obtained from 38 patients aged 3 to 11 years, of which 16 received enzyme replacement therapy. At the time of the interview, 32/38 were alive, 4/32 had died, and outcome data for 2 patients were missing. The age of onset of the first symptoms varied significantly: from 1 year 10 months to 3 years 6 months. The median age at which children were diagnosed with NCL2 was 52 months, or 4 years 5 months, but it varied from 12 to 96 months. At the time of diagnosis, in addition to epileptic seizures and delayed speech development, ataxia and loss of motor development, as well as other symptoms, were already noted. EEG was performed in 73% of all cases (with photostimulation only in 34%). MRI at an early stage of the disease was performed in only 40%. Only 46% of patients receive (or have ever received) enzyme replacement therapy. In 41% of cases, enzyme replacement therapy was not prescribed due to the long-term diagnosis of NCL2, which led to a palliative status and refusal of the patients’ parents from therapy.Conclusion. Early diagnosis of NCL2 is difficult due to the non-specificity of the first symptoms, as well as due to the poor awareness of doctors about the disease and the main methods of its diagnosis, which leads to late prescribing of enzyme replacement therapy.

Intravitreal enzyme replacement therapy to prevent retinal disease progression in children with neuronal ceroid lipofuscinosis type 2 (CLN2): Interim safety report

Intravitreal enzyme replacement therapy to prevent retinal disease progression in children with neuronal ceroid lipofuscinosis type 2 (CLN2): Interim safety report

Buffy Coat Score as a Biomarker of Treatment Response in Neuronal Ceroid Lipofuscinosis Type 2.

The introduction of intracerebroventricular (ICV) enzyme replacement therapy (ERT) for treatment of neuronal ceroid lipofuscinosis type 2 (CLN2) disease has produced dramatic improvements in disease management. However, assessments of therapeutic effect for ICV ERT are limited to clinical observational measures, namely the CLN2 Clinical Rating Scale, a subjective measure of motor and language performance. There is a need for an objective biomarker to enable assessments of disease progression and response to treatment. To address this, we investigated whether the proportion of cells with abnormal storage inclusions on electron microscopic examination of peripheral blood buffy coats could act as a biomarker of disease activity in CLN2 disease. We conducted a prospective longitudinal analysis of six patients receiving ICV ERT. We demonstrated a substantial and continuing reduction in the proportion of abnormal cells over the course of treatment, whereas symptomatic scores revealed little or no change over time. Here, we proposed the use of the proportion of cells with abnormal storage as a biomarker of response to therapy in CLN2. In the future, as more tissue-specific biomarkers are developed, the buffy coats may form part of a panel of biomarkers in order to give a more holistic view of a complex disease.

Freezing of Gait as the Initial Manifestation of Neuronal Ceroid Lipofuscinosis Type 6: a Case Report

Freezing of Gait as the Initial Manifestation of Neuronal Ceroid Lipofuscinosis Type 6: a Case Report

Cathepsin D: Analysis of its potential role as an amyloid beta degrading protease

Proteolysis catalyzed by the major lysosomal aspartyl protease cathepsin-D (CTSD) appears to be of pivotal importance for proteostasis within the central nervous system and in neurodegeneration. Neuronal Ceroid Lipofuscinosis (NCL) type 10 is caused by a lack of CTSD leading to a defective autophagic flow and pathological accumulation of proteins. We previously demonstrated a therapeutic-relevant clearance of protein aggregates after dosing a NCL10 mouse model with recombinant human pro-cathepsin-D (proCTSD). Similar results could be achieved in cells and mice accumulating α-synuclein. Prompted by these positive effects and our in vitro findings showing that cathepsin-D can cleave the Alzheimer's Disease (AD)-causing amyloid beta peptides (Aβ), we envisaged that such a treatment with proCTSD could similarly be effective in clearance of potentially toxic Aβ species.We demonstrated that CTSD is able to cleave human Aβ1–42 by using liquid chromatography-mass spectrometry. Intracerebral dosing of proCTSD in a NCL10 (CTSD knockout) mouse model revealed uptake and processing of CTSD to its mature and active form. However, the re-addition of CTSD did not obviously affect intracellular APP processing or the generation of soluble APP and Aβ-species. ProCTSD treated HEK cells in comparison with untreated cells were found to contain comparable levels of soluble and membrane bound APP and Aβ-species. Also, the early intracranial application (P1 and P20) of proCTSD in the 5xFAD mouse model did not change Aβ pathology, plaque number and plaque composition and neuroinflammation, however we observed an increased level of Aβ1–42 in the CSF.Our data confirm proteolytic cleavage of human Aβ1–42 by CTSD but exclude a prominent role of CTSD in APP processing and Aβ degradation in our in vitro and in vivo models.

Identification of a TPP1 Q278X Mutation in an Iranian Patient with Neuronal Ceroid Lipofuscinosis 2: Literature Review and Mutations Update

Neuronal ceroid lipofuscinoses type 2 (CLN2), the most common form of Batten disease, is caused by TPP1 loss of function, resulting in tripeptidyl peptidase-1 enzyme deficiency and cerebral accumulation of lipopigments. Clinical hallmarks include epileptic seizures, vision loss, progressive movement disorder, ataxia, and eventually death. Diagnosis is often delayed due to the rarity of the conditions. Results: Here, we report a case presenting with clinical features of CLN2, carrying a homozygous novel nonsense variant in TPP1 (NM_000391:c.C832T, (p.Q278*), rs1352347549). Moreover, we performed a comprehensive literature review regarding previously identified disease-causing TPP1 mutations and genotype-phenotype correlations. Conclusion: Depending on the type of mutation, different phenotypes are observed in patients with CLN2, suggesting that the severity of phenotypes is related to the genotype of the patients.

Role of Electroencephalogram (EEG) and Magnetic Resonance Imaging (MRI) Findings in Early Recognition and Diagnosis of Neuronal Ceroid Lipofuscinosis Type 2 Disease.

Neuronal ceroid lipofuscinosis type 2 (CLN2) disease is a very rare neurodegenerative lysosomal storage disorder. Progression is rapid and irreversible, making early diagnosis crucial for timely treatment. A group of pediatric neurologists and neuroradiologists with expertise in CLN2 convened to discuss early electroencephalogram (EEG) and magnetic resonance imaging (MRI) findings in CLN2 diagnosis. Of 18 CLN2 cases, 16 (88.9%) had background slowing and 16 (88.9%) had epileptiform discharges on initial EEG. Seven of 17 (41.2%) patients who received intermittent low-frequency photic stimulation had a photoparoxysmal response. Initial MRIs showed subtle cerebellar (n = 14, 77.8%) or cerebral (n = 9, 50.0%) atrophy, white matter abnormalities (n = 11, 61.1%), and basal ganglia T2 hypointensity (n = 6, 33.3%), which became more apparent on follow-up MRI. The recognition of even subtle cerebellar atrophy and white matter signal changes in children aged 2-5 years who present with language delay, new-onset seizures, and an EEG with epileptiform discharges and background slowing should prompt investigation for CLN2. Because these early signs are not unique to CLN2, genetic testing is essential early in the diagnostic journey.

Clinical case of neuronal ceroid lipofuscinosis type II in a child

Neuronal ceroid lipofuscinosis is a group of hereditary neurodegenerative diseases inherited by an autosomal recessive trait. This disease is the most common neurodegenerative pathology in children with a prevalence of 1:1,000,000 to 1:14,000 in the world. Currently, 14 genetically different forms of this pathology have been identified, which are characterized by the accumulation of abnormal lipofuscin-like material in the lysosomes of nerve cells, progressive and selective destruction of neurons. In neuronal ceroid lipofuscinosis, there is a defect in the gene that translates various lysosomal enzymes. Due to the insufficiency of the enzyme tripeptidyl peptidase 1, an accumulation of pathological autofluorescent lipopigment is observed in the central nervous system (CNS) of the patient, leading to violations of the normal function of neurons. Clinically, the disease manifests at the age of 34 years, in the form of progressive myoclonic epilepsy, mental and motor disorders, delays and stops in development. The article describes data on the prevalence, clinical features and therapy of this pathology, and also presents a clinical case with the onset of the disease in a child aged 2 years 11 months. The clinical case demonstrates the difficulties of diagnosing this pathology due to the rarity of this pathology, a wide range of differential diagnostics, the duration and high cost of molecular genetic studies. An early diagnosing would make it possible to explain the nature of epilepsy, to choose a rational therapy for this disease in a timely manner.