[A case of GM1 gangliosidoses].

This article describes a case which seek medical advice for 2 months due to retrogressive development, The discovery of the characteristic fundus of the macular cherry-red spot is a key clue for further genetic analysis, GLB compound heterozygous mutations is detected, and enzymology results show that the acid B-galactose glucoside enzyme significantly decrease, fundus inspection help diagnosis GM1 gangliosidoses.

Quantitative longitudinal natural history of 8 gangliosidoses-conceptual framework and baseline data of the German 8-in-1 disease registry. A cross-sectional analysis.

PURPOSE: Gangliosidoses are a group of inherited neurogenetic autosomal recessive lysosomal storage disorders usually presenting with progressive macrocephaly, developmental delay, and regression, leading to significant morbidity and premature death. A quantitative definition of the natural history would support and enable clinical development of specific therapies. METHODS: Single disease registry of 8 gangliosidoses (NCT04624789). Cross-sectional analysis of baseline data in N = 26 patients. Primary end point: disease severity assessed by the 8-in-1 score. Secondary end points: first neurologic sign or symptom observed (1) by parents and (2) by physicians, diagnostic delay, as well as phenotypical characterization. Tertiary end points: neurologic outcomes (development, ataxia, dexterity) and disability. RESULTS: The 8-in-1 score quantitatively captured severity of disease. Parents recognized initial manifestations (startle reactions) earlier than physicians (motor developmental delay and hypotonia). Median diagnostic delay was 3.16 (interquartile range 0.69-6.25) years. In total, 8 patients presented with late-infantile phenotypes. CONCLUSION: Data in this registry raise awareness of these rare and fatal conditions to accelerate diagnosis, inform counseling of afflicted families, define quantitative end points for clinical trials, and can serve as historical controls for future therapeutic studies. We provide further insight into the rare late-infantile phenotype for GM2-gangliosidosis. Longitudinal follow up is planned.

Optimization of Enzyme Essays to Enhance Reliability of Activity Measurements in Leukocyte Lysates for the Diagnosis of Metachromatic Leukodystrophy and Gangliosidoses.

(1) Lysosomal storage diseases are rare inherited disorders with no standardized or commercially available tests for biochemical diagnosis. We present factors influencing the quality of enzyme assays for metachromatic leukodystrophy (MLD) and gangliosidoses (GM1; GM2 variants B and 0) and validate the reliability and stability of testing in a retrospective analysis of 725 samples. (2) Patient leukocytes were isolated from ethylene-diamine-tetra-acetic acid (EDTA) blood and separated for subpopulation experiments using density gradient centrifugation or magnetic cell separation. Enzyme activities in whole leukocyte lysate and leukocyte subpopulations were determined. (3) The enzyme activities in leukocyte subpopulations differed significantly. Compared to lymphocytes, the respective enzyme activities were 2.31-4.57-fold higher in monocytes and 1.64-2.81-fold higher in granulocytes. During sample preparation, a considerable amount of the lysosomal enzymes was released from granulocytes. Nevertheless, with the sample preparation method used here, total leukocyte count proved to be more accurate than total protein amount as a reference unit for enzyme activities. Subsequent analysis of 725 individuals showed clear discrimination of enzyme activities in patient samples (48 MLD; 21 gangliosidoses), with a sensitivity of 100% and specificity of 98-99%.

Genotype, phenotype and in silico pathogenicity analysis of HEXB mutations: Panel based sequencing for differential diagnosis of gangliosidosis.

OBJECTIVES: Gangliosidosis is an inherited metabolic disorder causing neurodegeneration and motor regression. Preventive diagnosis is the first choice for the affected families due to lack of straightforward therapy. Genetic studies could confirm the diagnosis and help families for carrier screening and prenatal diagnosis. An update of HEXB gene variants concerning genotype, phenotype and in silico analysis are presented. PATIENTS AND METHODS: Panel based next generation sequencing and direct sequencing of four cases were performed to confirm the clinical diagnosis and for reproductive planning. Bioinformatic analyses of the HEXB mutation database were also performed. RESULTS: Direct sequencing of HEXA and HEXB genes showed recurrent homozygous variants at c.509G>A (p.Arg170Gln) and c.850C>T (p.Arg284Ter), respectively. A novel variant at c.416T>A (p.Leu139Gln) was identified in the GLB1 gene. Panel based next generation sequencing was performed for an undiagnosed patient which showed a novel mutation at c.1602C>A (p.Cys534Ter) of HEXB gene. Bioinformatic analysis of the HEXB mutation database showed 97% consistency of in silico genotype analysis with the phenotype. Bioinformatic analysis of the novel variants predicted to be disease causing. In silico structural and functional analysis of the novel variants showed structural effect of HEXB and functional effect of GLB1 variants which would provide fast analysis of novel variants. CONCLUSIONS: Panel based studies could be performed for overlapping symptomatic patients. Consequently, genetic testing would help affected families for patients' management, carrier detection, and family planning's.

In situ detection of GM1 and GM2 gangliosides using immunohistochemical and immunofluorescent techniques for auxiliary diagnosis of canine and feline gangliosidoses.

BACKGROUND: GM1 and GM2 gangliosidoses are progressive neurodegenerative lysosomal storage diseases resulting from the excessive accumulation of GM1 and GM2 gangliosides in the lysosomes, respectively. The diagnosis of gangliosidosis is carried out based on comprehensive findings using various types of specimens for histological, ultrastructural, biochemical and genetic analyses. Therefore, the partial absence or lack of specimens might have resulted in many undiagnosed cases. The aim of the present study was to establish immunohistochemical and immunofluorescent techniques for the auxiliary diagnosis of canine and feline gangliosidoses, using paraffin-embedded brain specimens stored for a long period. RESULTS: Using hematoxylin and eosin staining, cytoplasmic accumulation of pale to eosinophilic granular materials in swollen neurons was observed in animals previously diagnosed with GM1 or GM2 gangliosidosis. The immunohistochemical and immunofluorescent techniques developed in this study clearly demonstrated the accumulated material to be either GM1 or GM2 ganglioside. CONCLUSIONS: Immunohistochemical and immunofluorescent techniques using stored paraffin-embedded brain specimens are useful for the retrospective diagnosis of GM1 and GM2 gangliosidoses in dogs and cats.

Biomarkers of central nervous system inflammation in infantile and juvenile gangliosidoses.

BACKGROUND: The gangliosidoses (Tay-Sachs disease, Sandhoff disease, and GM1-gangliosidosis) are progressive neurodegenerative diseases caused by lysosomal enzyme activity deficiencies and consequent accumulation of gangliosides in the central nervous system (CNS). The infantile forms are distinguished from the juvenile forms by age of onset, rate of disease progression, and age of death. There are no approved treatments for the gangliosidoses. In search of potential biomarkers of disease, we quantified 188 analytes in CSF and serum from living human patients with longitudinal (serial) measurements. Notably, several associated with inflammation were elevated in the CSF of infantile gangliosidosis patients, and less so in more slowly progressing forms of juvenile gangliosidosis, but not in MPS disease. Thirteen CSF and two serum biomarker candidates were identified. Five candidate biomarkers were distinguished by persistent elevation in the CSF of patients with the severe infantile phenotype: ENA-78, MCP-1, MIP-1α, MIP-1ß, and TNFR2. Correspondence of abnormal elevation with other variables of disease-i.e., severity of clinical phenotype, differentiation from changes in serum, and lack of abnormality in other neurodegenerative lysosomal diseases-identifies these analytes as biomarkers of neuropathology specific to the gangliosidosis diseases.

Gangliosidoses.

The gangliosidoses comprise a family of lysosomal storage diseases characterized by the accumulation of complex glycosphingolipids in the nervous system and other tissues, secondary to the deficient activity of lysosomal hydrolases or their associated activator proteins. GM1 and GM2 gangliosidosis are associated with deficiency of ß-galactosidase and ß-hexosaminidase respectively. All gangliosidoses are characterized by progressive neurodegeneration, the severity of which is proportional to the residual enzyme activity. The GM1 gangliosidoses are characterized by dysostosis, organomegaly and coarsening in their most severe forms, whereas children with classic infantile GM2 gangliosidosis (Tay-Sachs disease) are usually spared systemic involvement, except in the case of the Sandhoff variant, in which organomegaly may occur. Cherry-red macular spots occur in the early onset forms of the gangliosidoses, but are less frequently seen in the less severe, later onset phenotypes. Macrocephaly, an exaggerated startle response, cognitive decline, seizures, ataxia, and progressive muscular atrophy may occur in different forms of gangliosidosis. The diagnosis is made by assay of enzyme activity, and can be confirmed by mutation analysis. Carrier screening for Tay-Sachs disease has been remarkably successful in reducing the incidence of this disease in the at-risk Ashkenazi population. There are no proven disease-modifying therapies for the gangliosidoses.

"Cherry-red spot" or "perifoveal white patch"?

The color of the normal fovea, red in Caucasians, contrasts with the surrounding retina, whose colour is altered by accumulation of metabolic products, causing retinal pallor. In this photo-essay, we present the fundus photographs of 3 patients of different race, all with metabolic disease, each of whose fovea contrasts with the surrounding retina, and for whom the expression "cherry red spot" is not necessarily accurate. We suggest that the term "perifoveal white patch" describes this characteristic finding more accurately. We also discuss the pathological entities that may produce this striking appearance, along with its histological and anatomical basis.

Fetal diagnosis of galactosialidosis (protective protein/cathepsin A deficiency).

The fetal diagnosis of galactosialidosis is performed by measuring carboxypeptidase (cathepsin A) activity in cultured villous cells and by immunofluorescence analysis with an antibody against an oligopeptide corresponding to the N-terminal domain of the human mature protective protein. Neither carboxypeptidase activity nor immunofluorescence was detected in cultured villous cells derived from an at-risk fetus or in cultured fibroblasts derived from the sister with galactosialidosis. Neuraminidase and beta-galactosidase activities were also confirmed to be deficient or low. A direct assay system for protective protein/cathepsin A is useful for the accurate prenatal diagnosis of galactosialidosis.

[Sialidosis and galactosialidosis as the cause of non-immunologic hydrops fetalis]. / Sialidose und Galaktosialidose als Ursache des nicht-immunologischen Hydrops fetalis.

Two cases of non-immunological hydrops fetalis (NIHF) presenting with massive ascites are reported; in both patients an oligosaccharid-pattern in the urine typical for sialidosis resp. galactosialidosis was found. The cerebral sonography of both patients showed streaky echo enhancement in the region of the thalamostriatal vessels, which was interpreted as calcification of the vessels. The courses of the patients were characterised by recurrent infections, hepatosplenomegaly and myoclonus. Relevant literature reports on a large variability in the clinical appearance of oligosaccharidoses. The diagnosis of sialidosis is confirmed in cultured fibroblasts by the deficiency of alpha-N-acetylneuraminidase and, in case of galactosialidosis by the additional lack of beta-galactosidase. The precise diagnosis in NIHF is of increasing interest for prenatal diagnostic as well as for neonatological management.

Gangliosidosis GM1 Tipo I: forma infantil / Gangliosidosis GM1 Type I: infantile form

Se presenta un caso de Gangliosidosis GM1, tipo I, de diagnóstico tardío para llamar la atención sobre una enfermedad hereditaria. Se trata de una lactante de sexo femenino que a pesar de presentar los signos principales de la enfermedad no fue reconocida tempranamente. El diagnóstico se confirmó a los 6 meses por dosificación de la enzima beta-galactosidasa lisosomal en leucocitos. Se destaca la falla de la atención primaria y la necesidad de un diagnóstico seguro para poder realizar un adecuado consejo genético

High-resolution loading tests in the study of genetic heterogeneity in gangliosidosis fibroblasts.

GM1- and GM2-gangliosides were isolated from brain and radiolabelled. The labelled moieties were localized by hydrolysis with lysosomal enzymes, followed by thin-layer chromatography of the products. High-resolution loading tests with labelled gangliosides were developed and found to differentiate infantile and juvenile forms of GM1- and GM2-gangliosidoses as well as the identification of B, O and AB types of GM2-gangliosidosis.

The clinical aspects of adult hexosaminidase deficiencies.

The authors describe the clinical phenotypes of hexosaminidase deficiencies (GM2 gangliosidosis). The symptoms, differently combined, include cerebellar ataxia, motor neuron disease, dystonia, psychosis, neurovegetative troubles with different severity. Morphological changes are evident in rectal, muscle or nerve biopsies. Minor clinical changes are described in carriers from a family. A chronic GM2 gangliosidosis has to be suspected in any atypical case with the above-mentioned symptoms with autosomal-recessive inheritance.

[Hereditary lysosomal diseases in Mexico. III. Laboratory diagnosis of sphingolipidosis]. / Enfermedades hereditarias lisosomales en México. III. Diagnóstico de laboratorio para esfingolipidosis.

Enzymatic determinations of the levels of lysosomal enzymes in serum or leukocytes samples have been carried out for the diagnosis of 7 sphingolipidosis. This methodology has allowed us to study 49 homozygotes and 33 close relatives at risk for the carrier state of a particular sphingolipidosis. So far we have diagnosed: 21 Gaucher's disease patients, 17 metachromatic leukodistrophy, 4 Niemann-Pick, 4 GM2 gangliosidosis, 2 Fabry and one GM1 gangliosidosis. Limitations in the performance and interpretation of the levels of the defective enzyme in heterozygotes, homozygotes and those variants not detected with the assays described are discussed.

[Three siblings with type 3 GM1-gangliosidosis--pathophysiology of dystonia and MRI findings].

GM1-gangliosidosis is a rare neurovisceral storage disease caused by an inherited deficiency of acid beta-galactosidase. The characteristic neurological feature of type 3 (adult or chronic) GM1-gangliosidosis is usually a slowly progressive dystonia with dysarthria due to predominant involvement of basal ganglia. About 20 adult patients with this disorder have been reported in the literature. However, there are no reports of 3 brothers with type 3 GM1-gangliosidosis, and MRI findings. Case 1 (proband): A 28-year-old man was hospitalized because of facial grimace, dysarthria, and generalized dystonia. He was born after normal pregnancy and delivery. His development was normal until 3 years of age when the difficulties of speaking and walking were noticed by his parents. These neurological abnormalities progressed slowly and facial grimace and dystonic movements occurred 7 years later. He could not walk at 22 years of age. On admission, he was bedridden with marked scoliosis and subluxation of the mandibule. The communication was possible only by pointing the words written on the board. Case 2: A 33-year-old man, elder brother of case 1, showed the similar neurological features and clinical course. Slit-lamp examination revealed corneal opacities which were located in the deep stroma. Case 3: A 33-year-old man, elder brother of case 1 or case 2. At age 10-11, he noted similar symptoms as case 1 or case 2. The severity of dystonia was milder than his brothers. A diagnosis of GM1-gangliosidosis in three patients was made on the basis of the following data.(ABSTRACT TRUNCATED AT 250 WORDS)

[Diagnosis of lysosomal storage diseases. Pathomorphologic and biochemical possibilities]. / Diagnostik lysosomaler Speicherkrankheiten. Pathomorphologische und biochemische Möglichkeiten.

Optical light and electron microscopy were used in studies into two cases of infantile GM2-gangliosidosis. The results are reported in this paper. The correlation has been evident between histological and ultrastructural findings. Reliable delimitation between two different variants of infantile GM2-gangliosidosis was achieved through biochemical investigation of postmortally cultured skin fibroblasts. A classical form with isolated hexosaminidase-A defect (Tay-Sachs disease) was distinguished from a second variant with complete defect of both isoenzymes of hexosaminidase (Sandhoff's disease). Biochemical investigation of postmortally cultured fibroblasts today has become indispensable to enlargement of autopsy findings from other storage diseases, as well.

[The use of loading tests with labeled GM1-ganglioside for differential diagnosis of GM1-gangliosidosis]. / Ispol'zovanie nagruzochnykh testov s pomoshch'iu mechenogo GM1-gangliozida dlia differentsial'noi diagnostiki GM1-gangliozidoza.

Kinetics of GM1-ganglioside accumulation was studied in fibroblast cultures from patients with various forms of GM1-gangliosidosis using the labelled native substrate GM1-ganglioside isolated from human brain. A shape of accumulation curves in the plot was shown to depend on GM1-ganglioside concentration in a medium in juvenile form of the disease. Use of a number of the fibroblast strains and optimal concentration of GM1-ganglioside 20 micrograms/ml enabled to carry out allele differentiation of the juvenile form of GM1-gangliosidosis from infantile and normal forms, thus suggesting that the loading tests could be applied to pre- and postnatal diagnosis of GM1-gangliosidosis.