Magnetic resonance imaging findings and novel mutations in GM1 gangliosidosis

Volume mismatch indicates tumors in paramedial bithalamic diseases: a retrospective study

OBJECTIVE

This study aimed to investigate the diagnostic performance of volume mismatch sign on discriminating paramedial bithalamic tumors from non-tumors.

METHODS

In this study, we recruited patients with tumors or non-tumors of the paramedial bithalamus. We confirmed the diagnosis by pathology, laboratory tests documented in medical records, medical imaging at the baseline, or through at least 1 year of follow-up. Cases with paramedial thalamic lesions on only one side or purely midbrain illnesses were excluded. Additionally, any case without involvement of the medial thalami (i.e., those with one or both-sided anterior, lateral, or posterior thalamic lesions) was excluded. Two neuroradiologists were trained independently to evaluate volume mismatch sign on magnetic resonance T2-weighted images or T2 fluid-attenuated inversion recovery images. A positive volume mismatch sign means that the ratio of the larger-sided lesion volume to the smaller-sided lesion volume is >150%. The volume of each lesion was calculated by multiplying the anteroposterior diameter by the left-right diameter and by the height of the lesion and then dividing by 2. The kappa value was calculated to show the consistency between the two observers. The chi-square test was used to evaluate differences in volume mismatch sign between the bilthalamic midline tumor and non-tumor groups. The positive (PPV) and negative (NPV) predictive values, sensitivity, and specificity were calculated to evaluate the ability of volume mismatch sign to differentiate paramedial bilateral thalamus tumors from non-tumors. A two-tailed P ≤ 0.05 was considered to be statistically significant. The analyses were performed using the statistical software SPSS version 26.

RESULTS

A total of 96 patients were enrolled in this study between March 2012 and October 2022. A high agreement between the two observers on the volume mismatch sign of bilateral paramedian thalamic diseases was found, and the Kappa value was 0.828. A statistically significant difference was observed for the volume mismatch sign between the paramedial bithalamic tumor and the non-tumorous groups (χ2 = 35.465, P < 0.001). The presence of volume mismatch sign in paramedial bithalamic illnesses predicted the presence of tumors with a sensitivity and specificity of 69.2% and 90.9%, respectively, and PPV and NPV were 90.0% and 71.4%.

CONCLUSION

Volume mismatch sign may indicate tumors in paramedian bithalamic diseases.

Late-infantile GM1 gangliosidosis: A case report

RATIONALE

Monosialotetrahexosylganglioside (GM1) gangliosidosis is a rare lysosomal storage disorder caused by the deficiency of ß-galactosidase. Because clinical symptoms of GM1 gangliosidosis overlap with other neurodevelopmental disorders, the diagnosis of this disease is not easy, specifically in late infantile GM1 gangliosidosis. This report described a case of late-infantile GM1 gangliosidosis mistaken for juvenile idiopathic arthritis.

PATIENT CONCERNS

A 16-year-old girl was referred to our hospital due to persistent multiple joint deformities and mental retardation, which could not be explained by juvenile idiopathic arthritis.

DIAGNOSIS

We made a diagnosis of late infantile GM1 gangliosidosis through enzyme assays and genetic testing after a skeletal survey.

INTERVENTIONS

The patient underwent cervical domeplasty and laminectomy for cord compression and received rehabilitation treatment.

OUTCOMES

The patient is receiving multidisciplinary care at a tertiary center for variable skeletal disease and conditions associated with GM1 gangliosidosis.

LESSONS

Late infantile GM1 gangliosidosis should be considered in the differential diagnosis of progressive neurologic decline and skeletal dysostosis.

Substrate reduction therapy with Miglustat in pediatric patients with GM1 type 2 gangliosidosis delays neurological involvement: A multicenter experience

BACKGROUND

In GM1 gangliosidosis the lack of function of β-galactosidase results in an accumulation of GM1 ganglioside and related glycoconjugates in visceral organs, and particularly in the central nervous system, leading to severe disability and premature death. In the type 2 form of the disease, early intervention would be important to avoid precocious complications. To date, there are no effective therapeutic options in preventing progressive neurological deterioration. Substrate reduction therapy with Miglustat, a N-alkylated sugar that inhibits the enzyme glucosylceramide synthase, has been proposed for the treatment of several lysosomal storage disorders such as Gaucher type 1 and Niemann Pick Type C diseases. However, data on Miglustat therapy in patients with GM1 gangliosidosis are still scarce.

METHODS

We report here the results of Miglustat administration in four Italian children (average age: 55 months, range 20-125) affected by GM1 gangliosidosis type 2 treated in three different Italian pediatric hospitals specialized in metabolic diseases.

CONCLUSION

This treatment was safe and relatively well tolerated by all patients, with stabilization and/or slowing down of the neurological progression in three subjects.

Bilateral lesions of the basal ganglia and thalami (central grey matter)-pictorial review

The basal ganglia and thalami are paired deep grey matter structures with extensive metabolic activity that renders them susceptible to injury by various diseases. Most pathological processes lead to bilateral lesions, which may be symmetric or asymmetric, frequently showing characteristic patterns on imaging studies. In this comprehensive pictorial review, the most common and/or typical genetic, acquired metabolic/toxic, infectious, inflammatory, vascular and neoplastic pathologies affecting the central grey matter are subdivided according to the preferential location of the lesions: in the basal ganglia, in the thalami or both. The characteristic imaging findings are described with emphasis on the differential diagnosis and clinical context.

Ceramide signalling in inherited and multifactorial brain metabolic diseases

In recent years, research on sphingolipids, particularly ceramides, has attracted increased attention, revealing the important roles and many functions of these molecules in several human neurological disorders. The nervous system is enriched with important classes of sphingolipids, e.g., ceramide and its derivatives, which compose the major portion of this group, particularly in the form of myelin. Ceramides have also emerged as important nodes for lipid signalling, both inside the cell and between cells. Until recently, knowledge about ceramides in the nervous system was limited, but currently, multiple links between ceramide signalling and neurological diseases have been reported. Alterations in the regulation of ceramide pathobiology have been shown to influence the risk of developing neurometabolic diseases. Thus, these molecules are critically important in the maintenance and development of the nervous system and are culprits or major contributors to the development of brain disorders, either inherited or multifactorial. In the present review, we highlight the critical role of ceramide signalling in several different neurological disorders as well as the effects of their perturbations and discuss how this emerging class of bioactive sphingolipids has attracted interest in the field of neurological diseases.

Diagnostic challenge for the rare lysosomal storage disease: Late infantile GM1 gangliosidosis

BACKGROUND

GM1 gangliosidosis is a rare lysosomal storage disorder caused by GLB1 mutations. Because of its extreme rarity and symptoms that overlap with other neurodegenerative diseases, its diagnosis is sometimes challenging, especially in the late infantile form with less severe phenotype. We aim to expand the clinical and genetic spectrum of late infantile GM1 gangliosidosis.

METHODS

We confirmed a diagnosis of GM1 gangliosidosis based on GLB1 mutations and/or the deficiency of β-galactosidase activity. We identified the first two cases by whole-exome sequencing, and then the other six cases by direct sequencing of GLB1 with enzyme analysis.

RESULTS

All eight patients presented with developmental delay or regression during late infancy and later developed epilepsy, mostly intractable generalized tonic seizures. No clinical signs of storage disorders were noted except for skeletal abnormalities. Interestingly, we found aspartate transaminase (AST) elevations alone with normal alanine transaminase (ALT) levels in all patients. The recurrent mutation, p.D448V in GLB1, accounted for 50.0% of total alleles in our cohort.

CONCLUSIONS

With a high index of clinical suspicion, skeletal survey and AST level would be important for early diagnosis of GM1 gangliosidosis. In addition, we would highlight the clinical usefulness of whole-exome sequencing in the diagnosis of non-classical presentation of ultra-rare neurodegenerative disease in children.

In Vivo NMR Studies of the Brain with Hereditary or Acquired Metabolic Disorders

Metabolic disorders, whether hereditary or acquired, affect the brain, and abnormalities of the brain are related to cellular integrity; particularly in regard to neurons and astrocytes as well as interactions between them. Metabolic disturbances lead to alterations in cellular function as well as microscopic and macroscopic structural changes in the brain with diabetes, the most typical example of metabolic disorders, and a number of hereditary metabolic disorders. Alternatively, cellular dysfunction and degeneration of the brain lead to metabolic disturbances in hereditary neurological disorders with neurodegeneration. Nuclear magnetic resonance (NMR) techniques allow us to assess a range of pathophysiological changes of the brain in vivo. For example, magnetic resonance spectroscopy detects alterations in brain metabolism and energetics. Physiological magnetic resonance imaging (MRI) detects accompanying changes in cerebral blood flow related to neurovascular coupling. Diffusion and T1/T2-weighted MRI detect microscopic and macroscopic changes of the brain structure. This review summarizes current NMR findings of functional, physiological and biochemical alterations within a number of hereditary and acquired metabolic disorders in both animal models and humans. The global view of the impact of these metabolic disorders on the brain may be useful in identifying the unique and/or general patterns of abnormalities in the living brain related to the pathophysiology of the diseases, and identifying future fields of inquiry.

Myelin abnormalities in the optic and sciatic nerves in mice with GM1-gangliosidosis

GM1-gangliosidosis is a glycosphingolipid lysosomal storage disease involving accumulation of GM1 and its asialo form (GA1) primarily in the brain. Thin-layer chromatography and X-ray diffraction were used to analyze the lipid content/composition and the myelin structure of the optic and sciatic nerves from 7- and 10-month old β-galactosidase (β-gal) +/? and β-gal −/− mice, a model of GM1gangliosidosis. Optic nerve weight was lower in the β-gal −/− mice than in unaffected β-gal +/? mice, but no difference was seen in sciatic nerve weight. The levels of GM1 and GA1 were significantly increased in both the optic nerve and sciatic nerve of the β-gal −/− mice. The content of myelin-enriched cerebrosides, sulfatides, and plasmalogen ethanolamines was significantly lower in optic nerve of β-gal −/− mice than in β-gal +/? mice; however, cholesteryl esters were enriched in the β-gal −/− mice. No major abnormalities in these lipids were detected in the sciatic nerve of the β-gal −/− mice. The abnormalities in GM1 and myelin lipids in optic nerve of β-gal −/− mice correlated with a reduction in the relative amount of myelin and periodicity in fresh nerve. By contrast, the relative amount of myelin and periodicity in the sciatic nerves from control and β-gal −/− mice were indistinguishable, suggesting minimal pathological involvement in sciatic nerve. Our results indicate that the greater neurochemical pathology observed in the optic nerve than in the sciatic nerve of β-gal −/− mice is likely due to the greater glycolipid storage in optic nerve.

Serial MRI features of canine GM1 gangliosidosis: a possible imaging biomarker for diagnosis and progression of the disease

GM1 gangliosidosis is a fatal neurodegenerative lysosomal storage disease caused by an autosomal recessively inherited deficiency of β-galactosidase activity. Effective therapies need to be developed to treat the disease. In Shiba Inu dogs, one of the canine GM1 gangliosidosis models, neurological signs of the disease, including ataxia, start at approximately 5 months of age and progress until the terminal stage at 12 to 15 months of age. In the present study, serial MR images were taken of an affected dog from a model colony of GM1 gangliosidosis and 4 sporadic clinical cases demonstrating the same mutation in order to characterize the MRI features of this canine GM1 gangliosidosis. By 2 months of age at the latest and persisting until the terminal stage of the disease, the MR findings consistently displayed diffuse hyperintensity in the white matter of the entire cerebrum on T2-weighted images. In addition, brain atrophy manifested at 9 months of age and progressed thereafter. Although a definitive diagnosis depends on biochemical and genetic analyses, these MR characteristics could serve as a diagnostic marker in suspect animals with or without neurological signs. Furthermore, serial changes in MR images could be used as a biomarker to noninvasively monitor the efficacy of newly developed therapeutic strategies.

MR imaging findings in 2 cases of late infantile GM1 gangliosidosis

SUMMARY

Late infantile GM1 gangliosidosis is a rare lysosomal disorder characterized by mental deterioration and progressive spastic, cerebellar, and extrapyramidal signs, without facial dysmorphisms and organomegaly. Neuroimaging findings have been reported in only a few cases. Here we report on predominant globus pallidus MR signal-intensity abnormalities in 2 patients with the late infantile form of GM1 gangliosidosis.

GM1 gangliosidosis: review of clinical, molecular, and therapeutic aspects

GM(1) gangliosidosis is a lysosomal storage disorder due to deficiency of the beta-galactosidase enzyme. This deficiency results in accumulation of GM(1) gangliosides and related glycoconjugates in the lysosomes leading to lysosomal swelling, cellular damage, and organ dysfunction. The disease is lethal in the infantile and juvenile forms. To date, up to 102 mutations distributed along the beta-galactosidase gene (GLB1) have been reported. This review gives an overview of the clinical and molecular findings in patients with GM(1) gangliosidosis. Furthermore, it describes therapeutic approaches which are currently under investigation in animal models of the disease.

Complete correction of enzymatic deficiency and neurochemistry in the GM1-gangliosidosis mouse brain by neonatal adeno-associated virus-mediated gene delivery

GM1-gangliosidosis is a glycosphingolipid (GSL) lysosomal storage disease caused by autosomal recessive deficiency of lysosomal acid beta-galactosidase (betagal), and characterized by accumulation of GM1-ganglioside and GA1 in the brain. Here we examined the effect of neonatal intracerebroventricular (i.c.v.) injection of an adeno-associated virus (AAV) vector encoding mouse betagal on enzyme activity and brain GSL content in GM1-gangliosidosis (betagal(-/-)) mice. Histological analysis of betagal distribution in 3-month-old AAV-treated betagal(-/-) mice showed that enzyme was present at high levels throughout the brain. Biochemical quantification showed that betagal activity in AAV-treated brains was 7- to 65-fold higher than in wild-type controls and that brain GSL levels were normalized. Cerebrosides and sulfatides, which were reduced in untreated betagal(-/-) mice, were restored to normal levels by AAV treatment. In untreated betagal(-/-) brains, cholesterol was present at normal levels but showed abnormal cellular distribution consistent with endosomal/lysosomal localization. This feature was also corrected in AAV-treated mice. The biochemical and histological parameters analyzed in this study showed that normal brain neurochemistry was achieved in AAV-treated betagal(-/-) mice. Therefore we show for the first time that neonatal AAV-mediated gene delivery of lysosomal betagal to the brain may be an effective approach for treatment of GM1-gangliosidosis.

Brain proton magnetic resonance spectroscopy and neuromuscular pathology in a patient with GM1 gangliosidosis

The authors report the clinical, neuroradiologic, and neuromuscular pathological findings in a patient with GM1 gangliosidosis. The proton magnetic resonance spectroscopy, previously reported in a single patient with GM1 gangliosidosis, detected a mild reduction of N-acetylaspartate, consistent with relative paucity of axons and neurons and increased levels of myoinositol suggestive of gliotic white matter changes along with the accumulation of an additional compound that could represent either guanidinoacetate or Gal beta 1-6Gal beta 1-4)GlcNAc, an oligosaccharide previously isolated from the urine of GM1 gangliosidosis patients. Although these findings will have to be further confirmed in more patients with GM1 gangliosidosis, they suggest that proton magnetic resonance spectroscopy may provide useful end points to assess the efficacy of novel treatments that could soon become clinically available. Histologically, no significant alterations were found in axons, but there was evidence of redundant and inappropriately folded myelin, which is a feature attributed to disturbed axon-glial interactions.

Decreased T2 signal in the thalami may be a sign of lysosomal storage disease

INTRODUCTION

Lysosomal disorders are rare and are caused by genetically transmitted lysosomal enzyme deficiencies. A decreased T2 signal in the thalamus has occasionally been reported.

AIMS

Because the finding of bilateral abnormal signal intensity of the thalamus on T2-weighted images has not been systematically reviewed, and its value as a diagnostic tool critically evaluated, we carried out a systematic review of the literature.

METHODS

Articles in English with 30 trios of keywords were collected from PubMed. Exclusion criteria were lack of conventional T2-weighted images in the protocol and not being a human study. Finally, 111 articles were included. The thalamus was considered affected only if mentioned in the text or in the figure legends.

RESULTS

Some 117 patients with various lysosomal diseases and five patients with ceruloplasmin deficiency were reported to have a bilateral decrease in T2 signal intensity. At least one article reported a bilateral decrease in signal intensity of the thalami on T2-weighted images in association with GM1 and GM2 gangliosidosis and with Krabbe's disease, aspartylglucosaminuria, mannosidosis, fucosidosis, and mucolipidosis IV. Furthermore, thalamic alteration was a consistent finding in several types of neuronal ceroid lipofuscinosis (NCL) including CLN1 (infantile NCL), CLN2 (classic late infantile NCL), CLN3 (juvenile NCL), CLN5 (Finnish variant late infantile NCL), and CLN7 (Turkish variant late infantile NCL).

CONCLUSION

A decrease in T2 signal intensity in the thalami seems to be a sign of lysosomal disease.

Neuroimaging findings in infantile GM1 gangliosidosis

GM1 gangliosidosis is an autosomal recessive glycosphingolipid storage disease caused by defects in the enzyme beta-galactosidase. Three clinical forms (infantile-, juvenile-, and adult-onset) of the disease are recognized. Patients with infantile GM1 gangliosidosis present at birth or shortly thereafter with somatic and bony changes, followed by severe neurological deterioration ultimately leading to death within the first 2 years of life. We present the brain CT, MRI and MR spectroscopy (MRS) findings in a 17-month-old Turkish girl with infantile GM1 gangliosidosis. Neuroimaging findings in patients with infantile GM1 gangliosidosis have been reported only in a few cases. In this study, MRS of the thalamus was performed to study the metabolic changes in GM1 gangliosidosis. We showed a a decreased NAA/Cr ration and an increased Cho/Cr ratio. To our knowledge, this is the first report of magnetic resonance spectroscopy findings in type-1 GM1 gangliosidosis.