Sandhoff Disease Research Articles

Glycosphingolipids Associated Metabolic Disorders

Lipids play diverse roles in sustaining life, including energy storage, hormonal balance, and cellular communication. Alterations in lipid metabolism can lead to various disorders, including diabetes, atherosclerosis, cancer, and neurodegenerative diseases. Among these disorders, lysosomal storage disorders (LSDs) related to glycosphingolipids metabolism present significant challenges. This review systematically analyzes the current literature on LSDs, focusing on classification, clinical presentations, diagnostic advancements, available treatments, and emerging therapeutic strategies. Glycosphingolipids biosynthesis, particularly its role in viral dissemination and melanin synthesis, underscores its significance in health and disease. Additionally, the review delves into specific LSDs, such as Fabry disease, Gaucher disease, Sandhoff disease, Tay-Sachs disease, and Krabbe disease, highlighting their pathophysiology, prevalence, and treatment options. Enzyme replacement therapy and hematopoietic stem cell transplantation are mainstays in LSD treatment, but gene therapy shows promise. Furthermore, the review explores the role of glycosphingolipids in non-communicable diseases like diabetes, cancer, atherosclerosis, lupus, Alzheimer's, Parkinson's disease, and influenza. Understanding glycosphingolipid metabolism offers insights into disease mechanisms and therapeutic targets, paving the way for improved treatments and ultimately enhancing patient outcomes.

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.

Role of Botulinum Toxin in Treatment of Secondary Dystonia: A Case Series and Overview of Literature.

Dystonia can present in primary and secondary forms, depending on co-occurring symptoms and syndromic associations. In contrast to primary dystonia, secondary forms of dystonia are often associated with lesions in the putamen or globus pallidus. Such disorders are commonly neurodegenerative or neurometabolic conditions which produce varied neurologic as well as systemic manifestations other than dystonia. Chemo-denervation with botulinum toxin has been successfully used for focal or segmental dystonia. However, studies evaluating the effect of BoNT therapy on patients with secondary dystonia are sparse, given the heterogeneity in etiology and presentation. We present a series of patients with secondary dystonia who were managed with botulinum toxin therapy. Patients included in this series had a confirmed neurometabolic cause of dystonia. A total of 14 patients, with ages ranging from 17 to 36 years, with disorders including Wilson's disease, pantothenate kinase-associated neurodegeneration (PKAN), Niemann-Pick disease type C (NPC), glutaric aciduria type 1, Sanfilippo syndrome (Mucopolysaccharidosis Type IIIb), and GM2 gangliosidosis (Sandhoff disease) are presented. Most patients experienced a mild to moderate improvement in treated dystonia with benefits ranging from 6 to 12 weeks, with the median length of the benefits lasting approximately eight weeks, without any significant adverse effects. Although the secondary causes of dystonia are complex and diverse, our presented data and the available reports of the use of botulinum toxin support the conclusion that chemo-denervation plays an important role in symptom alleviation.

Tandem mass spectrometric enzyme assay for simultaneous detection of Tay-Sachs and Sandhoff diseases in dried blood spots for newborn screening

GM2 gangliosidosis is a group of rare lysosomal storage disorders (LSDs) including Tay-Sachs disease (TSD) and Sandhoff disease (SD), caused by deficiency in activity of either β-hexosaminidase A (HexA) or both β-hexosaminidase A and β-hexosaminidase B (Hex B). Methods for screening and diagnosis of TSD and SD include measurement and comparison of the activity of these two enzymes. Here we report a novel method for duplex screening of dried blood spots (DBS) for TSD and SD by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method requires incubation of a single 3 mm DBS punch with the assay cocktail followed by the injection into the LC-MS/MS. The performance of the method was evaluated by comparing the confirmed TSD and SD patient DBS to random healthy newborn DBS which showed easy discrimination between the three cohorts. The method is multiplexable with other LSD MS/MS enzyme assays which is critical to the continued expansion of the NBS panels.

Evidence of Lysosomal β-Hexosaminidase Enzymatic Activity Associated with Extracellular Vesicles: Potential Applications for the Correction of Sandhoff Disease.

Extracellular vesicles (EVs) can be isolated from biological fluids and cell culture medium. Their nanometric dimension, relative stability, and biocompatibility have raised considerable interest for their therapeutic use as delivery vehicles of macromolecules, namely nucleic acids and proteins. Deficiency in lysosomal enzymes and associated proteins is at the basis of a group of genetic diseases known as lysosomal storage disorders (LSDs), characterized by the accumulation of undigested substrates into lysosomes. Among them, GM2 gangliosidoses are due to a deficiency in the activity of lysosomal enzyme β-hexosaminidase, leading to the accumulation of the GM2 ganglioside and severe neurological symptoms. Current therapeutic approaches, including enzyme replacement therapy (ERT), have proven unable to significantly treat these conditions. Here, we provide evidence that the lysosomal β-hexosaminidase enzyme is associated with EVs released by HEK cells and that the EV-associated activity can be increased by overexpressing the α-subunit of β-hexosaminidase. The delivery of EVs to β-hexosaminidase-deficient fibroblasts results in a partial cross-correction of the enzymatic defect. Overall findings indicate that EVs could be a source of β-hexosaminidase that is potentially exploitable for developing therapeutic approaches for currently untreatable LSDs.

Sandhoff's Disease: A Case Report

Sandhoff disease is a rare inherited disorder within the sphingolipidosis family, characterized by the accumulation of lipids in the nervous system due to a deficiency in hexosaminidase types A and B enzymes. This condition leads to progressive neurological disorders and eventual blindness, often resulting in fatality before the age of 4. We present the case of an infant who was admitted for psychomotor regression and generalized hypotonia, with the diagnosis of Sandhoff disease being supported by ophthalmological examination findings. Confirmation of the diagnosis was achieved through exome sequencing.

Inherited metabolic disorders in Cyprus

Selective screening for inherited metabolic disorders (IMD) began in Cyprus in 1990. Over the last thirty-three years 7388 patients were investigated for IMD and 200 diagnoses were made (diagnostic yield 2.7%). The existence of a single laboratory of Biochemical Genetics for the whole island facilitated the creation of a national registry for IMD. The minimal prevalence of IMD in Cyprus is 53.3 cases per 100,000 live births. The most common group are disorders of amino acid metabolism (41.0%), followed by disorders of carbohydrate metabolism (16.5%), disorders of complex molecule degradation (16.5%), mitochondrial disorders (10.5%) and disorders of vitamin and co-factor metabolism (5.5%). Hyperphenylalaninaemia is the most common IMD (14.0%) followed by galactosaemia (7.0%), glutaric aciduria type I (5.5%) and MSUD (4.0%). Some disorders were found to have a relatively high incidence in specific communities, for example Sandhoff disease among the Cypriot Maronites and GM1 gangliosidosis in one particular area of the island. Other disorders were found to have a relatively higher overall incidence, compared to other Caucasian populations, for example galactosaemia, glutaric aciduria type I and MSUD, while fatty acid oxidation defects, Gaucher disease and classic PKU were found to have a relatively lower incidence. Molecular characterization of selected disorders revealed many novel genetic variants, specific to the Cypriot population.

236 Bilateral Intrathalamic Infusion of rAAVrh8-Hexa/Hexb in a Phase 1/2 Clinical Trial for Gene Therapy in Infantile and Juvenile Tay-Sachs and Sandhoff Disease; Surgical Technique

INTRODUCTION: Tay-Sachs (TSD) and Sandhoff (SD) diseases are rare,monogenic and severe neurodegenerative disorders due to Hexosaminidase A deficiency. We performed the first-in-human bilateral thalamic (BiTh) delivery of rAAVrh8-HEXA/HEXB in 8 children in a Phase 1/2 clinical trial. METHODS: Stereotactic infusion cannula placement was performed using ROSA robotic platform. Bilateral trajectories were planned via the trans-frontal route..Head stabilization was accomplished using radiolucent horse-shoe head rest and radiolucent pin-skull clamps. Flexible infusion cannulas were placed through small drill holes using ROSA guidance. Cannula stabilization was achieved using a construct which combined the Navigus brain biopsy platform and flexible cannula bolt. Insertion accuracy was verified with intraoperative CT images. Patients received one of the three doses in each thalamus: 180 mcl (5.87E + 12vg), 360 mcl (1.17E + 13vg) or 720 mcl (2.35E + 13vg). Drug infusion rate was 4 mcl/minute and completed in 90-360 minutes depending on drug dosage. RESULTS: Eight patients received treatment; 5 infants (6, 11, 13, 17, and 20 months) and 3 juvenile (5, 6, 12 years). Duration of follow up was 2-28 months. Outcome assessments included safety, CSF biochemistry, MRI/MRS/DTI, and neurodevelopmental observations. Surgery and drug infusions were well-tolerated. Post-infusion MRIs showed signal enhancement volume coverage in thalamus from 8%-44% parallel to escalating doses. The only surgery related complication was superficial wound dehiscence in two patients. Infants showed partial stabilization or improvement, including in oral feeding and myelination. In juveniles, dystonic posturing worsened after dosing in all 3 patients treated. Two patients died much later from reasons unrelated to surgery or drug infusion. CONCLUSIONS: Surgery for BiTh infusion of rAAVrh8-HEXA/HEXB for gene therapy in infants with TSD and SD is well-tolerated. Patients respond well to treatment with some stabilization or improvement.

Cinnamic acid, a natural plant compound, exhibits neuroprotection in a mouse model of Sandhoff disease via PPARα.

Tay-Sachs disease (TSD) and its severe form Sandhoff disease (SD) are autosomal recessive lysosomal storage metabolic disorders, which often result into excessive GM2 ganglioside accumulation predominantly in lysosomes of nerve cells. Although patients with these diseases appear normal at birth, the progressive accumulation of undegraded GM2 gangliosides in neurons leads to early death accompanied by manifestation of motor difficulties and gradual loss of behavioral skills. Unfortunately, there is still no effective treatment available for TSD/SD. The present study highlights the importance of cinnamic acid (CA), a naturally occurring aromatic fatty acid present in a number of plants, in inhibiting the disease process in a transgenic mouse model of SD. Oral administration of CA significantly attenuated glial activation and inflammation and reduced the accumulation of GM2 gangliosides/glycoconjugates in the cerebral cortex of Sandhoff mice. Besides, oral CA also improved behavioral performance and increased the survival of Sandhoff mice. While assessing the mechanism, we found that oral administration of CA increased the level of peroxisome proliferator-activated receptor α (PPARα) in the brain of Sandhoff mice and that oral CA remained unable to reduce glycoconjugates, improve behavior and increase survival in Sandhoff mice lacking PPARα. Our results indicate a beneficial function of CA that utilizes a PPARα-dependent mechanism to halt the progression of SD and thereby increase the longevity of Sandhoff mice.

Genetic variant reanalysis reveals a case of Sandhoff disease with onset of infantile epileptic spasm syndrome

BackgroundSandhoff disease (SD) i s an autosomal recessive lysosomal disease with clinical manifestations such as epilepsy, psychomotor retardation and developmental delay. However, infantile SD with onset of infantile epilepsy spasm syndrome (IESS) is extremely rare.Case presentationThe case presented here was a 22-month-old boy, who presented with IESS and psychomotor retardation/regression at 6 months of age. The patient showed progressive aggravation of seizures and excessive startle responses. The whole exome sequencing data, which initially revealed negative results, were reanalyzed and indicated a homozygous mutation at the c.1613 + 4del splice site of the HEXB gene. The activities of β-hexosaminidase A and total hexosaminidase were significantly decreased. The fundus examination showed cherry red spots at the macula.ConclusionsIESS can be an epileptic phenotype of infantile SD. Clinical phenotypes should be adequately collected in genetic testing. In the case of negative sequencing results, gene variant reanalysis can be performed when the patients show clinically suspicious indications.

The utilization of a combination of TLC-UHPL/MS-MS and molecular networking in the assessment and prediction of Fabry and Sandhoff diseases

The utilization of a combination of TLC-UHPL/MS-MS and molecular networking in the assessment and prediction of Fabry and Sandhoff diseases

Innate immune sensing of lysosomal dysfunction drives multiple lysosomal storage disorders.

Lysosomal storage disorders (LSDs), which are characterized by genetic and metabolic lysosomal dysfunctions, constitute over 60 degenerative diseases with considerable health and economic burdens. However, the mechanisms driving the progressive death of functional cells due to lysosomal defects remain incompletely understood, and broad-spectrum therapeutics against LSDs are lacking. Here, we found that various gene abnormalities that cause LSDs, including Hexb, Gla, Npc1, Ctsd and Gba, all shared mutual properties to robustly autoactivate neuron-intrinsic cGAS-STING signalling, driving neuronal death and disease progression. This signalling was triggered by excessive cytoplasmic congregation of the dsDNA and DNA sensor cGAS in neurons. Genetic ablation of cGAS or STING, digestion of neuronal cytosolic dsDNA by DNase, and repair of neuronal lysosomal dysfunction alleviated symptoms of Sandhoff disease, Fabry disease and Niemann-Pick disease, with substantially reduced neuronal loss. We therefore identify a ubiquitous mechanism mediating the pathogenesis of a variety of LSDs, unveil an inherent connection between lysosomal defects and innate immunity, and suggest a uniform strategy for curing LSDs.

Intrathecal delivery of a bicistronic AAV9 vector expressing β-hexosaminidase A corrects Sandhoff disease in a murine model: A dosage study

The pathological accumulation of GM2 ganglioside associated with Tay-Sachs disease (TSD) and Sandhoff disease (SD) occurs in individuals who possess mutant forms of the heterodimer β-hexosaminidase A (Hex A) because of mutation of the HEXA and HEXB genes, respectively. With a lack of approved therapies, patients experience rapid neurological decline resulting in early death. A novel bicistronic vector carrying both HEXA and HEXB previously demonstrated promising results in mouse models of SD following neonatal intravenous administration, including significant reduction in GM2 accumulation, increased levels of Hex A, and a 2-fold extension of survival. The aim of the present study was to identify an optimal dose of the bicistronic vector in 6-week-old SD mice by an intrathecal route of administration along with transient immunosuppression, to inform possible clinical translation. Three doses of the bicistronic vector were tested: 2.5e11, 1.25e11, and 0.625e11 vector genomes per mouse. The highest dose provided the greatest increase in biochemical and behavioral parameters, such that treated mice lived to a median age of 56weeks (>3 times the lifespan of the SD controls). These results have direct implications in deciding a human equivalent dose for TSD/SD and have informed the approval of a clinical trial application (NCT04798235).

PCR247 Is the Symptomatology of Infantile Tay-Sachs and Infantile Sandhoff Disease Identical? Data from an International Registry

PCR247 Is the Symptomatology of Infantile Tay-Sachs and Infantile Sandhoff Disease Identical? Data from an International Registry

The diagnostic journey for patients with late-onset GM2 Gangliosidoses

Late-onset forms of GM2 gangliosidosis―mainly, Tay-Sachs disease and Sandhoff disease―are under-recognized in clinical practice. In these rare lysosomal storage disorders, deficiency of β-hexosaminidase A results in excessive accumulation of GM2 ganglioside primarily within neurons, leading to cell death and progressive neurodegenerative symptoms, including ataxia, dysarthria, muscle weakness, tremors, atrophy, and psychosis. Presentation is variable and often mimics more common neurodegenerative disorders. We conducted semi-structured interviews on GM2 gangliosidoses diagnosis and treatment with five experts, 30 neurologists, and 28 patients and caregivers. Symptom onset occurred during adolescence/early adulthood in 92% of patients (median age: 14 years). Patients first visited a healthcare provider at a median age of 20 years and received a GM2 diagnosis at a median age of 26 years. Nearly all patients reported problems with their legs and balance starting from symptom onset. Problems with memory, attention span, speech and fatigue were reported more after diagnosis. Patients visited an average of eight healthcare providers before receiving a diagnosis; 64% were diagnosed by a neurologist. Four neurologists (13%) in our sample were aware that there are late-onset forms of GM2 gangliosidosis. The path to diagnosis is long for this late-onset form of a classically fatal infantile disease.

Efficacy of Adeno-Associated Virus Serotype 9-Mediated Gene Therapy for AB-Variant GM2 Gangliosidosis.

GM2 gangliosidoses are a group of neurodegenerative lysosomal storage disorders that are characterized by the accumulation of GM2 gangliosides (GM2), leading to rapid neurological decline and death. The hydrolysis of GM2 requires the specific synthesis, processing, and combination of products of three genes-HEXA, HEXB, and GM2A-within the cell's lysosomes. Mutations in these genes result in Tay-Sachs disease, Sandhoff disease, or AB-variant GM2 gangliosidosis (ABGM2), respectively. ABGM2, the rarest of the three types, is characterized by a mutation in the GM2A gene, which encodes the GM2 activator (GM2A) protein. Being a monogenic disease, gene therapy is a plausible and likely effective method of treatment for ABGM2. This study aimed at assessing the effects of administering a one-time intravenous treatment of single-stranded Adeno-associated virus serotype 9 (ssAAV9)-GM2A viral vector at a dose of 1 × 1014 vector genomes (vg) per kilogram per mouse in an ABGM2 mouse model (Gm2a-/-). ssAAV9-GM2A was administered at 1-day (neonatal) or 6-weeks of age (adult-stage). The results demonstrated that, in comparison to Gm2a-/- mice that received a vehicle injection, the treated mice had reduced GM2 accumulation within the central nervous system and had long-term persistence of vector genomes in the brain and liver. This proof-of-concept study is a step forward towards the development of a clinically therapeutic approach for the treatment of patients with ABGM2.

Enhanced production of N-acetyl-glucosaminidase by marineAeromonas caviae CHZ306 in bioreactor.

N-Acetyl-glucosaminidases (GlcNAcases) are exoenzymes found in a wide range of living organisms, which have gained great attention in the treatment of disorders related to diabetes, Alzheimer's, Tay-Sachs', and Sandhoff's diseases; the control of phytopathogens; and the synthesis of bioactive GlcNAc-containing products. Aiming at future industrial applications, in this study, GlcNAcase production bymarine Aeromonas caviae CHZ306 was enhanced first in shake flasks in terms of medium composition and then in bench-scale stirred-tank bioreactor in terms of physicochemical conditions. Stoichiometric balance between the bioavailability of carbon and nitrogen in the formulated culture medium, as well as the use of additional carbon and nitrogen sources, played a central role in improving the bioprocess, considerably increasing the enzyme productivity. The optimal cultivation medium was composed of colloidal α-chitin, corn steep liquor, peptone A, and mineral salts, in a 5.2 C:N ratio. Optimization of pH, temperature, colloidal α-chitin concentration, and kLa conditions further increased GlcNAcase productivity. Under optimized conditions in bioreactor (i.e., 34°C, pH 8 and kLa 55.2h-1), GlcNAcase activity achieved 173.4 U.L-1 after 12h of cultivation, and productivity no less than 14.45U.L-1.h-1 corresponding to a 370-fold enhancement compared to basal conditions.

Life-Limiting Peripheral Organ Dysfunction in Feline Sandhoff Disease Emerges after Effective CNS Gene Therapy.

GM2 gangliosidosis is usually fatal by 5 years of age in its 2 major subtypes, Tay-Sachs and Sandhoff disease. First reported in 1881, GM2 gangliosidosis has no effective treatment today, and children succumb to the disease after a protracted neurodegenerative course and semi-vegetative state. This study seeks to further develop adeno-associated virus (AAV) gene therapy for human translation. Cats with Sandhoff disease were treated by intracranial injection of vectors expressing feline β-N-acetylhexosaminidase, the enzyme deficient in GM2 gangliosidosis. Hexosaminidase activity throughout the brain and spinal cord was above normal after treatment, with highest activities at the injection sites (thalamus and deep cerebellar nuclei). Ganglioside storage was reduced throughout the brain and spinal cord, with near complete clearance in many regions. While untreated cats with Sandhoff disease lived for 4.4 ± 0.6 months, AAV-treated cats lived to 19.1 ± 8.6 months, and 3 of 9 cats lived >21 months. Correction of the central nervous system was so effective that significant increases in lifespan led to the emergence of otherwise subclinical peripheral disease, including megacolon, enlarged stomach and urinary bladder, soft tissue spinal cord compression, and patellar luxation. Throughout the gastrointestinal tract, neurons of the myenteric and submucosal plexuses developed profound pathology, demonstrating that the enteric nervous system was inadequately treated. The vector formulation in the current study effectively treats neuropathology in feline Sandhoff disease, but whole-body targeting will be an important consideration in next-generation approaches. ANN NEUROL 2023;94:969-986.

Clinical and genetic features of a case with juvenile onset sandhoff disease

BackgroundSandhoff disease (SD) is a rare neurological disease with high clinical heterogeneity. SD in juvenile form is much rarer and it is often misdiagnosed in clinics. Therein, it is necessary to provide more cases and review the literature on juvenile onset SD.Case presentationA 14 years-old boy with eight years of walking difficulties, and was ever misdiagnosed as spinocerebellar ataxia. We found this patient after genetic testing carried rs201580118 and a novel gross deletion in HEXB (g.74012742_74052694del). Through review the literature, we found that was the first gross deletion identified at the 3’end of HEXB, associated with juvenile onset SD from China.ConclusionThis case expanded our knowledge about the genotype and phenotype correlations in SD. Comprehensive genetic testing is important for the diagnosis of unexplained ataxia.

Ursodeoxycholic Acid Binds PERK and Ameliorates Neurite Atrophy in a Cellular Model of GM2 Gangliosidosis.

The Unfolded protein response (UPR), triggered by stress in the endoplasmic reticulum (ER), is a key driver of neurodegenerative diseases. GM2 gangliosidosis, which includes Tay-Sachs and Sandhoff disease, is caused by an accumulation of GM2, mainly in the brain, that leads to progressive neurodegeneration. Previously, we demonstrated in a cellular model of GM2 gangliosidosis that PERK, a UPR sensor, contributes to neuronal death. There is currently no approved treatment for these disorders. Chemical chaperones, such as ursodeoxycholic acid (UDCA), have been found to alleviate ER stress in cell and animal models. UDCA's ability to move across the blood-brain barrier makes it interesting as a therapeutic tool. Here, we found that UDCA significantly diminished the neurite atrophy induced by GM2 accumulation in primary neuron cultures. It also decreased the up-regulation of pro-apoptotic CHOP, a downstream PERK-signaling component. To explore its potential mechanisms of action, in vitro kinase assays and crosslinking experiments were performed with different variants of recombinant protein PERK, either in solution or in reconstituted liposomes. The results suggest a direct interaction between UDCA and the cytosolic domain of PERK, which promotes kinase phosphorylation and dimerization.