Niemann-Pick Disease Type Research Articles

Plasma phosphorylated-tau217 (p-tau217) is increased in Niemann-Pick disease type C

Plasma phosphorylated-tau217 (p-tau217) is increased in Niemann-Pick disease type C

Enhanced mGluR5 intracellular activity causes psychiatric alterations in Niemann Pick type C disease

Niemann-Pick disease Type C (NPC) is caused by mutations in the cholesterol transport protein NPC1 leading to the endolysosomal accumulation of the lipid and to psychiatric alterations. Using an NPC mouse model (Npc1nmf164) we show aberrant mGluR5 lysosomal accumulation and reduction at plasma membrane in NPC1 deficient neurons. This phenotype was induced in wild-type (wt) neurons by genetic and pharmacological NPC1 silencing. Extraction of cholesterol normalized mGluR5 distribution in NPC1-deficient neurons. Intracellular accumulation of mGluR5 was functionally active leading to enhanced mGluR-dependent long-term depression (mGluR-LTD) in Npc1nmf164 hippocampal slices. mGluR-LTD was lower or higher in Npc1nmf164 slices compared with wt when stimulated with non-membrane-permeable or membrane-permeable mGluR5 agonists, respectively. Oral treatment with the mGluR5 antagonist 2-chloro-4-((2,5-dimethyl-1-(4-(trifluoromethoxy)phenyl)-1H-imidazol-4-yl)ethynyl)pyridine (CTEP) reduced mGluR-LTD and ameliorated psychiatric anomalies in the Npc1nmf164 mice. Increased neuronal mGluR5 levels were found in an NPC patient. These results implicate mGluR5 alterations in NPC psychiatric condition and provide a new therapeutic strategy that might help patients suffering from this devastating disease.

Hospital dental care for patients with Niemann-Pick syndrome type B: a case report

The aim of this case report is to show the hospital dental approach to a patient with Niemann-Pick disease (NPD) type B. After her caregivers reported poor oral health, a 10-year-old girl was referred to a hospital. She was diagnosed with NPD type B 4 years ago, with involvement of the brain, nerves, liver, spleen, bone marrow, and lungs. A dental physical examination revealed chronic carious lesions in ten teeth, as well as four residual roots and poor oral hygiene. We chose a surgical block treatment based on the altered complementary exams, dental demands, and the systemic compromise caused by NPD type B. All decayed elements were restored with glass ionomer cement, and residual roots were extracted. The patient had no clinical signs of infection or hemorrhage after 20 days of post-surgical follow-up. Although rare, the presence of patients with NPD type B in the dental routine can occur, necessitating the development of an individualized and multidisciplinary treatment plan.

Decision tree insights analytics (DTIA) tool: an analytic framework to identify insights from large data records across fields of science

Abstract Supervised machine learning (SML) techniques have been developed since the 1960s. Most of their applications were oriented towards developing models capable of predicting numerical values or categorical output based on a set of input variables (input features). Recently, SML models’ interpretability and explainability were extensively studied to have confidence in the models’ decisions. In this work, we propose a new deployment method named Decision Tree Insights Analytics (DTIA) that shifts the purpose of using decision tree classification from having a model capable of differentiating the different categorical outputs based on the input features to systematically finding the associations between inputs and outputs. DTIA can reveal interesting areas in the feature space, leading to the development of research questions and the discovery of new associations that might have been overlooked earlier. We applied the method to three case studies: (1) nuclear reactor accident propagation, (2) single-cell RNA sequencing of Niemann-Pick disease type C1 in mice, and (3) bulk RNA sequencing for breast cancer staging in humans. The developed method provided insights into the first two. On the other hand, it showed some of the method’s limitations in the third case study. Finally, we presented how the DTIA’s insights are more agreeable with the abstract information gain calculations and provide more in-depth information that can help derive more profound physical meaning compared to the random forest’s feature importance attribute and K-means clustering for feature ranking.

NPC1 links cholesterol trafficking to microglial morphology via the gastrosome.

Microglia play important roles in brain development and homeostasis by removing dying neurons through efferocytosis. Morphological changes in microglia are hallmarks of many neurodegenerative conditions, such as Niemann-Pick disease type C. Here, NPC1 loss causes microglia to shift from a branched to an ameboid form, though the cellular basis and functional impact of this change remain unclear. Using zebrafish, we show that NPC1 deficiency causes an efferocytosis-dependent expansion of the microglial gastrosome, a collection point for engulfed material. In vivo and in vitro experiments on microglia and mammalian macrophages demonstrate that NPC1 localizes to the gastrosome, and its absence leads to cholesterol accumulation in this compartment. NPC1 loss and neuronal cell death synergistically affect gastrosome size and cell shape, increasing the sensitivity of NPC1-deficient cells to neuronal cell death. Finally, we demonstrate conservation of cholesterol accumulation and gastrosome expansion in NPC patient-derived fibroblasts, offering an interesting target for further disease investigation.

Graphene Microelectrode Arrays, 4D Structured Illumination Microscopy, and a Machine Learning Spike Sorting Algorithm Permit the Analysis of Ultrastructural Neuronal Changes During Neuronal Signaling in a Model of Niemann-Pick Disease Type C.

Simultaneously recording network activity and ultrastructural changes of the synapse is essential for advancing understanding of the basis of neuronal functions. However, the rapid millisecond-scale fluctuations in neuronal activity and the subtle sub-diffraction resolution changes of synaptic morphology pose significant challenges to this endeavor. Here, specially designed graphene microelectrode arrays (G-MEAs) are used, which are compatible with high spatial resolution imaging across various scales as well as permit high temporal resolution electrophysiological recordings to address these challenges. Furthermore, alongside G-MEAs, an easy-to-implement machine learning algorithm is developed to efficiently process the large datasets collected from MEA recordings. It is demonstrated that the combined use of G-MEAs, machine learning (ML) spike analysis, and 4D structured illumination microscopy (SIM) enables monitoring the impact of disease progression on hippocampal neurons which are treated with an intracellular cholesterol transport inhibitor mimicking Niemann-Pick disease type C (NPC), and show that synaptic boutons, compared to untreated controls, significantly increase in size, leading to a loss in neuronal signaling capacity.

Metronome-Guided Balance Exercises to Aid in Dynamic Balance and Postural Control in a Novel Genetic Presentation of Niemann–Pick Disease Type C: A Case Report

Abstract Niemann–Pick disease type C is a rare progressive lysosomal lipid storage disorder. The disorder is characterized by a range of neurological consequences and complications at different points of its progression including spasticity, incoordination, ataxia, supranuclear gaze palsy, asthenia, and balance impairment, with a higher risk of falls. Among various approaches to managing such a debilitating condition, the role of physical therapy in managing the symptoms of such patients is often limited or underreported in the literature. A combination of spasticity and ataxia leads to impaired timing of agonist–antagonist control. Therefore, balance loss and falls are the most prevalent symptoms. We advocated a 12-week metronome-guided balance training program. Niemann–Pick type C disease is a rare genetic phenomenon that often presents with multi-system changes at structural and functional levels for the patient. Metronome-guided balance training is beneficial for improving dynamic balance variables, including movement velocity, center of gravity sway velocity, and step width.

Global and Targeted Metabolomics for Revealing Metabolomic Alteration in Niemann-Pick Disease Type C Model Cells.

Niemann-Pick disease type C (NPC) is an inherited disorder characterized by a functional deficiency of cholesterol transport proteins. However, the molecular mechanisms and pathophysiology of the disease remain unknown. In this study, we identified several metabolite characteristics of NPC that may fluctuate in a cellular model of the disease, using both global and targeted metabolomic analyses by liquid chromatography/tandem mass spectrometry (LC-MS/MS). Three cell lines, HepG2 cells (wild-type[WT]) and two NPC model HepG2 cell lines in which NPC1 was genetically ablated (knockout [KO]1 and KO2), were used for metabolomic analysis. Data were subjected to enrichment analysis using the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. The enrichment analysis of global metabolomics revealed that 8 pathways in KO1 and 16 pathways in KO2 cells were notably altered. In targeted metabolomics for 15 metabolites, 4 metabolites in KO1 and 10 metabolites in KO2 exhibited statistically significant quantitative changes in KO1 or KO2 relative to WT. Most of the altered metabolites were related to creatinine synthesis and cysteine metabolism pathways. In the future, our objective will be to elucidate the relationship between these metabolic alterations and pathophysiology.

An expert rule-based approach for identifying infantile-onset Pompe disease patients using retrospective electronic health records

Pompe disease (OMIM #232300), a rare genetic disorder, leads to glycogen buildup in the body due to an enzyme deficiency, particularly harming the heart and muscles. Infantile-onset Pompe disease (IOPD) requires urgent treatment to prevent mortality, but the unavailability of these methods often delays diagnosis. Our study aims to streamline IOPD diagnosis in the UAE using electronic health records (EHRs) for faster, more accurate detection and timely treatment initiation. This study utilized electronic health records from the Abu Dhabi Healthcare Company (SEHA) healthcare network in the UAE to develop an expert rule-based screening approach operationalized through a dashboard. The study encompassed six diagnosed IOPD patients and screened 93,365 subjects. Expert rules were formulated to identify potential high-risk IOPD patients based on their age, particular symptoms, and creatine kinase levels. The proposed approach was evaluated using accuracy, sensitivity, and specificity. The proposed approach accurately identified five true positives, one false negative, and four false positive IOPD cases. The false negative case involved a patient with both Pompe disease and congenital heart disease. The focus on CHD led to the overlooking of Pompe disease, exacerbated by no measurement of creatine kinase. The false positive cases were diagnosed with Mitochondrial DNA depletion syndrome 12-A (SLC25A4 gene), Immunodeficiency-71 (ARPC1B mutation), Niemann–Pick disease type C (NPC1 gene mutation leading to frameshift), and Group B Streptococcus meningitis. The proposed approach of integrating expert rules with a dashboard facilitated efficient data visualization and automated patient screening, which aids in the early detection of Pompe disease. Future studies are encouraged to investigate the application of machine learning methodologies to enhance further the precision and efficiency of identifying patients with IOPD.

Assessment of the reliability, responsiveness, and meaningfulness of the scale for the assessment and rating of ataxia (SARA) for lysosomal storage disorders.

To evaluate the reliability, responsiveness, and validity of theScale for the Assessment and Rating of Ataxia (SARA) in patients with lysosomal storage disorders (LSDs) who present with neurological symptoms, and quantify the threshold for a clinically meaningful change. We analyzed data from three clinical trial cohorts (IB1001-201, IB1001-202, and IB1001-301) of patients with Niemann-Pick disease type C (NPC) and GM2 Gangliosidoses (Tay-Sachs and Sandhoff disease) comprising 122 patients and 703 visits. Reproducibility was described as re-test reliability between repeat baseline visits or baseline and post-treatment washout visits. Responsiveness was determined in relation to the Investigator's, Caregiver's, and Patient's Clinical Global Impression of Improvement (CGI-I). The CGI-I data was also used to quantify a threshold for a clinically meaningful improvement on the SARA scale. Using a qualitative methods approach, patient/caregiver interviews from the IB1001-301 trial were further used to assess a threshold of meaningful change as well as the breadth of neurological signs and symptoms captured and evaluated by the SARA scale. The Inter-Class Correlation (ICC) was 0.95 or greater for all three trials, indicating a high internal consistency/reliability. The mean change in SARA between repeat baseline and post-treatment washout visit assessments in all trials was -0.05, SD 1.98, i.e., minimal, indicating no significant differences, learning effects or other systematic biases. For the CGI-I responses and change in SARA scores, Area Under the Curve (AUC) values were 0.82, 0.71, and 0.77 for the Investigator's, Caregiver's, and Patient's CGI-I respectively, indicating strong agreement. Further qualitative analyses of the patient/caregiver interviews demonstrated a 1-point or greater change on SARA to be a clinically meaningful improvement which is directly relevant to the patient's everyday functioning and quality of life. Changes captured by the SARA were also paralleled by improvement in a broad range of neurological signs and symptoms and beyond cerebellar ataxia. Qualitative and quantitative data demonstrate the reliability and responsiveness of the SARA score as a valid measure of neurological signs and symptoms in LSDs with CNS involvement, such as NPC and GM2 Gangliosidoses. A 1-point change represents a clinically meaningful transition reflecting the gain or loss of complex function.

Advances in research on potential therapeutic approaches for Niemann-Pick C1 disease.

Niemann-Pick disease type C1 (NP-C1) is a rare and devastating recessive inherited lysosomal lipid and cholesterol storage disorder caused by mutations in the NPC1 or NPC2 gene. These two proteins bind to cholesterol and cooperate in endosomal cholesterol transport. Characteristic clinical manifestations of NP-C1 include hepatosplenomegaly, progressive neurodegeneration, and ataxia. While the rarity of NP-C1 presents a significant obstacle to progress, researchers have developed numerous potential therapeutic approaches over the past two decades to address this condition. Various methods have been proposed and continuously improved to slow the progression of NP-C1, although they are currently at an animal or clinical experimental stage. This overview of NP-C1 therapy will delve into different theoretical treatment strategies, such as small molecule therapies, cell-based approaches, and gene therapy, highlighting the complex therapeutic challenges associated with this disorder.

Npc1 deficiency impairs microglia function via TREM2-mTOR signaling in Niemann-Pick disease type C

Niemann-Pick disease Type C (NPC) is a neurodegenerative disease mainly caused by the mutation in NPC1 gene, leading to massive accumulation of unesterified cholesterol in the late endosome/lysosome of cells. Impaired phenotype of microglia is a hallmark in Npc1 mutant mice (Npc1−/− mice). However, the mechanism of Npc1 in regulating microglial function is still unclear. Here, we showed that the reactive microglia in the neonatal Npc1−/− mice indicated by the increased lysosome protein CD68 and phagocytic activity were associated with disrupted TREM2-mTOR signaling in microglia. Furthermore, in Npc1-deficient BV2 cells, genetic deletion of Trem2 partially restored microglial function, probably via restored mTOR signaling. Taken together, our findings indicated that loss of Npc1 in microglia caused changes of their morphologies and the impairment of lysosomal function, which were linked to the TREM2-mTOR signaling pathway.

A Potential Role for the Amyloid Precursor Protein in the Regulation of Interferon Signaling, Cholesterol Homeostasis, and Tau Phosphorylation in Niemann-Pick Disease Type C.

Niemann-Pick disease type C (NPC) is a rare and fatal neurological disorder caused by mutations in Npc1 or Npc2, with Npc1 accounting for 95% of cases. These mutations result in the functional loss of their respective proteins, causing cellular abnormalities characterized by disrupted lipid dysregulation, calcium dysfunction, elevated damage associated molecular patterns (DAMPs), and a pro-inflammatory environment. This cellular pathology ultimately triggers neurodegeneration, with the cerebellum being the earliest and most affected region. We have recently shown atypical activation of interferon signaling in the presymptomatic Npc1-/- mouse cerebellum and, to a lesser extent, in the cerebral cortex. In addition, we reported that the Amyloid Precursor Protein (APP) is an NPC disease modifier. Loss of APP function leads to widespread neurodegeneration in the NPC brain, including exacerbated interferon signaling in the cerebellum. To better understand the role of APP as a disease modifier throughout the NPC brain, here we carried out a transcriptomic analysis of the cerebral cortex and cerebellum from 3-week-old Npc1-/- mice as well as age-matched controls in the presence and absence of APP. We report differential effects of APP loss of function in the cerebral cortex and cerebellum, including cholesterol and tau dysregulation, in both brain regions. Our findings demonstrate a novel link between APP loss and early pathogenic mechanisms in NPC.

Acid sphingomyelinase deficiency in France: a retrospective survival study

BackgroundAcid sphingomyelinase deficiency (ASMD) or Niemann–Pick disease types A, A/B, and B is a progressive, life-limiting, autosomal recessive disorder caused by sphingomyelin phosphodiesterase 1 (SMPD1) gene mutations. There is a need to increase the understanding of morbidity and mortality across children to adults diagnosed with ASMD.MethodsThis observational retrospective survey analysed medical records of patients with ASMD with retrievable data from 27 hospitals in France, diagnosed/followed up between 1st January 1990 and 31st December 2020. Eligible records were abstracted to collect demographic, medical/developmental history, and mortality data. Survival outcomes were estimated from birth until death using Kaplan–Meier survival analyses; standardised mortality ratio (SMR) was also explored.ResultsA total of 118 medical records of patients with ASMD (type B [n = 94], type A [n = 15], and type A/B [n = 9]) were assessed. The majority of patients were males (63.6%); the median [range] age at diagnosis was 8.0 [1.0–18.0] months (type A), 1.0 [0–3] year (type A/B), and 5.5 [0–73] years (type B). Overall, 30 patients were deceased at the study completion date; the median [range] age at death for patients with ASMD type A (n = 14) was 1 [0–3.6] year, type A/B (n = 6) was 8.5 [3.0–30.9] years, and type B (n = 10) was 57.6 [3.4–74.1] years. The median [95% confidence interval (CI)] survival age from birth in patients with ASMD type A and type A/B was 2.0 [1.8–2.7] years and 11.4 [5.5–18.5] years, respectively. Survival analysis in ASMD type B was explored using SMR [95% CI] analysis (3.5 [1.6–5.9]), which showed that age-specific deaths in the ASMD type B population were 3.5 times more frequent than those in the general French population. The causes of death were mostly severe progressive neurodegeneration (type A: 16.7%), cancer (type B: 16.7%), or unspecified (across groups: 33.3%).ConclusionsThis study illustrated a substantial burden of illness with high mortality rates in patients with ASMD, including adults with ASMD type B, in France.

Efficient breeding system of infertile Niemann-Pick disease type C model mice by in vitro fertilization and embryo transfer.

Niemann-Pick disease type C (NPC) is a lethal genetic disease with mutations in NPC1 or NPC2 gene. Npc1-deficient (Npc1-/-) mice have been used as a model for NPC pathogenesis to develop novel therapies for NPC. However, Npc1-/- mice are infertile; thus, securing sufficient numbers for translational research is difficult. Hence, we attempted reproductive engineering techniques such as in vitro fertilization (IVF) and sperm cryopreservation. For the first time, we succeeded in producing fertilized oocytes via IVF using male and female Npc1-/- mice. Fertilized oocytes were also obtained via IVF using cryopreserved sperm from Npc1-/- mice. The obtained fertilized oocytes normally developed into live pups via embryo transfer, and they eventually exhibited NPC pathogenesis. These findings are useful for generating an efficient breeding system that overcomes the reproductive challenges of Npc1-/- mice and will contribute to developing novel therapeutic methods using NPC model mice.

Accumulation of alkyl-lysophosphatidylcholines in Niemann-Pick disease type C1

Lysosomal function is impaired in Niemann-Pick disease type C1 (NPC1), a rare and inherited neurodegenerative disorder, resulting in late endosomal/lysosomal accumulation of unesterified cholesterol. The precise pathogenic mechanism of NPC1 remains incompletely understood. In this study, we employed metabolomics to uncover secondary accumulated substances in NPC1. Our findings unveiled a substantial elevation in the levels of three alkyl-lysophosphatidylcholine [alkyl-LPC, also known as lyso-platelet activating factor (PAF)] species in NPC1 compared to controls across various tissues, including brain tissue from individuals with NPC1, liver, spleen, cerebrum, cerebellum, and brain stem from NPC1 mice, as well as in both brain and liver tissue from NPC1 cats. The three elevated alkyl-LPC species were as follows: LPC O-16:0, LPC O-18:1, and LPC O-18:0. However, the levels of PAF 16:0, PAF 18:1, and PAF 18:0 were not altered in NPC1. In the NPC1 feline model, the brain and liver alkyl-LPC levels were reduced following 2-hydroxypropyl-β-cyclodextrin (HPβCD) treatment, suggesting that alkyl-LPCs are secondary storage metabolites in NPC1 disease. Unexpectedly, cerebrospinal fluid (CSF) levels of LPC O-16:0 and LPC O-18:1 were decreased in individuals with NPC1 compared to age-appropriate comparison samples, and their levels were increased in 80% of participants 2 years after intrathecal HPβCD treatment. The fold increases in CSF LPC O-16:0 and LPC O-18:1 levels were more pronounced in responders compared to nonresponders. This study identified alkyl-LPC species as secondary storage metabolites in NPC1 and indicates that LPC O-16:0 and LPC O-18:1, in particular, could serve as potential biomarkers for tracking treatment response in NPC1 patients.

CRISPR/Cas9 technology in the modeling of and evaluation of possible treatments for Niemann-Pick C.

Niemann-Pick disease type C (NPC) is a rare neurodegenerative condition resulted from mutations in NPC1andNPC2 genes. This cellular lipid transferring disorder mainly involves endocytosed cholesterol trafficking. The accumulation of cholesterol and glycolipids in late endosomes and lysosomes results in progressive neurodegeneration and death. Recently, genome editing technologies, particularly CRISPR/Cas9 have offered the opportunity to create disease models to screen novel therapeutic options for this disorder. Moreover, these methods have been used for the purpose of gene therapy. This review summarizes the studies that focused on the application of CRISPR/Cas9 technology for exploring the mechanism of intracellular cholesterol transferring, and screening of novel agents for treatment of NPC.

Differently increased volumes of multiple brain areas in Npc1 mutant mice following various drug treatments.

Niemann-Pick disease type C1 (NPC1, MIM 257220) is a heritable lysosomal storage disease characterized by a progressive neurological degeneration that causes disability and premature death. A murine model of Npc1-/- displays a rapidly progressing form of Npc1 disease, which is characterized by weight loss, ataxia, and increased cholesterol storage. Npc1-/- mice receiving a combined therapy (COMBI) of miglustat (MIGLU), the neurosteroid allopregnanolone (ALLO) and the cyclic oligosaccharide 2-hydroxypropyl-β-cyclodextrin (HPßCD) showed prevention of Purkinje cell loss, improved motor function and reduced intracellular lipid storage. Although therapy of Npc1-/- mice with COMBI, MIGLU or HPßCD resulted in the prevention of body weight loss, reduced total brain weight was not positively influenced. In order to evaluate alterations of different brain areas caused by pharmacotherapy, fresh volumes (volumes calculated from the volumes determined from paraffin embedded brain slices) of various brain structures in sham- and drug-treated wild type and mutant mice were measured using stereological methods. In the wild type mice, the volumes of investigated brain areas were not significantly altered by either therapy. Compared with the respective wild types, fresh volumes of specific brain areas, which were significantly reduced in sham-treated Npc1-/- mice, partly increased after the pharmacotherapies in all treatment strategies; most pronounced differences were found in the CA1 area of the hippocampus and in olfactory structures. Volumes of brain areas of Npc1-/- mice were not specifically changed in terms of functionality after administering COMBI, MIGLU, or HPßCD. Measurements of fresh volumes of brain areas in Npc1-/- mice could monitor region-specific changes and response to drug treatment that correlated, in part, with behavioral improvements in this mouse model.

Course of Niemann – Pick disease type A/B in the context of hematopoietic stem cell transplantation

Niemann – Pick disease type A/B (NPAB) is a rare severe inherited disease from the group of accumulation diseases with a defect in the acid sphingomyelinase gene (Niemann-Pick disease types B, A/B) (ASMD). Symptoms of damage to the nervous system and internal organs manifest in infancy, leading to disability, fatalities in childhood. NPAB is so far incurable. Optimal management of the disease requires a multidisciplinary team of physicians, specialists. The basis of therapy is the elimination of existing/forming complications, symptomatic treatment. Enzyme replacement therapy as a means of modifying the course of this disease is expected to slow down the progression of pathologic manifestations of the disease not related to the central nervous system lesions. Single cases of hematopoietic stem cell transplantation (HSCT) have been described in the treatment of ASMD, which is one of the new methods aimed at normalizing the level of acid sphingomyelinase, blood parameters, as well as reducing the severity of pathological visceral manifestations. However, the development of complications during HSCT, absence of positive therapeutic effect in severe CNS lesions does not allow to widely implement this method. Taking into account the contradictory data on the efficacy of HSCT in ASMD, further clinical studies are required. Analysis of 2 clinical cases of NPAB in children from the same family allowed us to reveal differences in the course and outcomes of the disease at verification of the diagnosis at birth followed by HSCT. Difficulties in diagnosing this extremely rare pathology, which requires a multidisciplinary approach, justify the need to improve methods of early diagnosis, including the organization of genetic risk determination, introduction of prenatal genetic testing before pregnancy.

Clinical and genetic analysis of Niemann-Pick disease type C with a novel NPC1 variant

BackgroundNiemann-Pick disease type C poses a significant challenge within the landscape of rare genetic disorders, marked by its connection to variants in the NPC1 or NPC2 genes. This autosomal recessive lipid storage disorder unfolds with a relentless progression of neurological deterioration and a distinctive hallmark of hepatosplenomegaly.Case presentationThis case report delves into the intricate presentation of a 9-year-old Iraqi boy exhibiting heightened walking instability and speech slurring. His medical history unfolds a series of challenges, including neonatal hyperbilirubinemia, hepatosplenomegaly, and recurrent nasal bleeding. A comprehensive physical examination reveals motor and neurological abnormalities such as an inability to squat and rise, vertical gaze palsy, and dysdiadochokinesia. Further investigations, encompassing laboratory tests and imaging studies, coupled with the identification of foamy cells in bone marrow smears, raise significant concerns about Niemann-Pick disease type C. By utilizing whole exome sequencing, we pinpointed a previously unreported homozygous variant—c.2925_2928delCTGC; p.Cys976PhefsTer6—found within exon 20 (NM_000271.5) of the proband’s NPC1 gene.ConclusionsThis study significantly advances our understanding of the c.2925_2928del (C976Ffs*6) variant in the NPC1 gene, shedding light on the complexities of Niemann-Pick disease type C. Beyond its scientific significance, the findings provide crucial insights for familial genetic counseling and prenatal diagnoses. This research expands our knowledge of the variant’s genetic landscape, making it a valuable resource in both academic and clinical settings, particularly for families dealing with Niemann-Pick disease type C.