Genetic and clinical analysis of a novel GLB1 gene variant in a Chinese patient with GM1-gangliosidosis / 中华医学遗传学杂志

OBJECTIVE@#To explore the genotype-phenotype correlation of a case with GM1-gangliosidosis caused by compound heterogenic variants in GLB1.@*METHODS@#Genomic DNA was extracted from peripheral blood samples from the patient and her parents. Trio-based whole-exome sequencing (WES) was performed for the family and suspected mutation was verified by Sanger sequencing.@*RESULTS@#The proband, a 2-year-3-month old Chinese girl, presented with psychomotor deterioration, absent speech, intellectual disabilities and behavior problem. Trio-based WES has identified compound heterozygosity for 2 variants in the GLB1 gene: NM_000404.2:c.1343A>T, p.Asp448Val and c.1064A>C, p.Gln355Pro (GRCh37/hg19),which was inherited from the mother and father, respectively. Homozygous or compound heterozygous pathogenic variants in GLB1, encoding β-galactosidase, are responsible for GM1-gangliosidosis,an autosomal recessive lysosomal storage disorder characterized by variable degrees of neurodegeneration and skeletal abnormalities. The p.Asp448Val variant has been classified as pathogenic for GM1 gangliosidosis in medical literatures for the reason that functional studies demonstrated that expression of the p.Asp448Val variant in COS-1 cells resulted in no detectable β-galactosidase activity compared to wild type GLB1. The p.Gln355Pro variant has not been reported in literatures or database. The variant is highly conserved residue (PM1), and was not found in either the Genome Aggregation Database or the 1000 Genomes Project (PM2) and was predicted to have a deleterious effect on the gene product by multiple in silico prediction tools (PP3). Next, the β-galactosidase activity of the patient's peripheral blood leukocytes was determined by fluorescent method. The result was 0.0 nmol/mg. It showed that the p.Gln355Pro variant also resulted in loss of β-galactosidase activity, thus the variant was classified into clinical pathogenic variant.@*CONCLUSION@#Our study expands the mutational spectrum of the GLB1 gene and provides genetic counseling for the family.

Evaluación neuropsicológica de un adulto colombiano diagnosticado con Síndrome de Morquio B / Neuropsychological assessment of a Colombian adult diagnosed with Morquio B Syndrome

Resumen El síndrome de Morquio B es una enfermedad rara y de baja prevalencia, por lo cual poco se ha estudiado sobre el funcionamiento neuropsicológico y estado cognitivo de quienes lo padecen. Este estudio de caso presenta los resultados del funcionamiento en atención, memoria, lenguaje, gnosias, praxias y funciones ejecutivas de un adulto colombiano diagnosticado con este síndrome. Se encontró que el paciente puede adquirir nuevo conocimiento; muestra memoria visoespacial y de trabajo verbal conservadas; repite, lee y escribe información sencilla que es conocida para él; sigue órdenes simples a partir de comandos verbales; muestra habilidades viso perceptuales y grafomotoras; tiene un desarrollo normal de pensamiento abstracto y asociativo, y es capaz de planear y solucionar problemas. Sin embargo, presenta dificultades en atención visual sostenida, atención audio-verbal, velocidad de procesamiento, lenguaje comprensivo, repetición y escritura al dictado de frases completas, flexibilidad cognitiva, y fluidez verbal semántica y fonológica. Se discute como factores más relevantes del funcionamiento cognitivo del paciente la relación entre el síndrome de Morquio B y la gangliosidosis GM1, y la falta de entrenamiento en el manejo de información de alta complejidad, dada su condición de desescolarización.

Abstract Since Morquio B syndrome is a low-prevalence rare disease, scarce evidence about neuropsychological functioning and cognitive status in diagnosed people is known. This case study shows the results of functioning in attention, memory, language, gnosias, praxias, and executive functions in a Colombian man diagnosed with this syndrome. It was found that the patient is capable of acquiring new information and exhibits preserved visuospatial and verbal working memory; he is also able to repeat, read and write simple information as long as it is familiar to him, and is capable of following simple verbal instructions with no difficulty; moreover, he displays preserved visuospatial and graphomotor abilities, has a normal development of abstract and associative thinking, and is able to plan and solve problems. Nonetheless, he exhibits difficulties in audio-verbal and sustained visual attention, as well as in processing speed, comprehensive language, repetition and writing of complete phrases, cognitive flexibility, and semantic and phonological verbal fluency. It is discussed the association between Morquio B syndrome and gangliosidosis GM1 as well as the lack of training in the management of highly complex information due to unschooling of this patient as the two most relevant factors of his cognitive functioning.

Novel mutations of GLB1 gene identified in a Chinese pedigree affected with GM1 gangliosidosis / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic cause for a child with growth retardation by next generation sequencing (NGS).@*METHODS@#Clinical data of the patient was collected. Peripheral venous blood samples were taken from the neonate and his parents. Targeted capturing and NGS were carried out to detect mutations of genes associated with inborn errors of metabolism. Suspected mutations were validated by Sanger sequencing.@*RESULTS@#The 15-month-old female patient was admitted to hospital for growth retardation for 4 months. Hypomyelination was found upon cranium MRI. Genetic testing revealed two novel insertional mutations in the GLB1 gene in the patient, namely c.2006-2007insT and c.475-476 insGGTCC.@*CONCLUSION@#The c.2006-2007insT and c.475-476 insGGTCC mutations of the GLB1 gene probably underlie the GM1 gangliosidosis resulting in the growth retardation in the child.

Identification and pathogenicity prediction of a novel GLB1 variant c.101T>C (p.Ile34Thr) in an infant with GM1 gangliosidosis / 中国当代儿科杂志

GM1 gangliosidosis is an autosomal recessive disorder caused by galactosidase beta1 (GLB1) gene variants which affect the activity of β-galactosidase (GLB). GLB dysfunction causes abnormalities in the degradation of GM1 and its accumulation in lysosome. This article reports the clinical and genetic features of a child with GM1 gangliosidosis. The girl, aged 2 years and 5 months, was referred to the hospital due to motor developmental regression for more than one year. Physical examination showed binocular deflection and horizontal nystagmus, but no abnormality was found on fundoscopy. The girl had increased muscular tone of the extremities, limitation of motion of the elbow, knee, and ankle joints, and hyperactive patellar tendon reflex. Blood biochemical examination showed a significant increase in aspartate aminotransferase. The 24-hour electroencephalographic monitoring detected frequent seizure attacks and diffuse θ wave activity, especially in the right hemisphere. Head magnetic resonance imaging showed thinner white matter in the periventricular region and diffuse high T2WI signal with unclear boundary. Three-dimensional reconstruction of white matter fiber tracts by diffusion tensor imaging showed smaller and thinner white matter fiber tracts, especially in the right hemisphere. Genetic analysis showed that the girl had compound heterozygous mutations of c.446C>T (p.Ser149Phe) and c.101T>C (p.Ile34Thr) in the GLB1 gene from her parents, among which c.101T>C (p.Ile34Thr) had not been reported in the literatures. The girl was finally diagnosed with GM1 gangliosidosis. Her conditions were not improved after antiepileptic treatment and rehabilitation training for 2 months.

Gangliosidose GM1 infantil ­ relato de caso / Child GM1 Gangliosidosis ­ Case Report

Introdução: A gangliosidose é uma doença caracterizada pelo acúmulo do substrato gangliosídeo nos lisossomos devido à deficiência da enzima betagalactosidase. É uma desordem rara, estimando-se uma incidência na população de 1:100.000 a 200.000. Clinicamente os pacientes apresentam graus variados de neurodegeneração e alterações esqueléticas, categorizadas pela gravidade e atividade residual da beta-galactosidase, podendo ocorrer dismorfismo facial, hepatoesplenomegalia, displasia esquelética, manchas maculares vermelhas, cegueira e até morte precoce. O atraso no desenvolvimento neuropsicomotor associada à degeneração do sistema nervoso central, pode levar o paciente a um quadro de hipotonia muscular generalizada progressiva, evoluindo para espasticidade e crises convulsivas. Objetivo: Relata-se caso de paciente masculino, apresentando alterações no desenvolvimento neuropsicomotor desde os oito meses, com elucidação diagnóstica através da clínica, exames de imagem e laboratoriais. Método: Busca em bancos de dados digitais artigos científicos que discorram sobre a gangliosidose. Resultados/Conclusão: A gangliosiodose é uma disordem rara, o que torna o relato de caso importante como fonte de pesquisa. (AU)

Introduction: Gangliosidosis is a disease characterized by accumulation of the ganglioside substrate in lysosomes due to beta-galactosidase enzyme deficiency. It is a rare disorder, with an incidence of 1: 100,000 to 200,000. Clinically the patients pres- ent varying degrees of neurodegeneration and skeletal changes, categorized by the gravity and residual activity of beta-galactosidase, being able to occur facial dysmorphism, hepatosplenomegaly, skeletal dysplasia, red macular spots, blind- ness and early death. Objective: Delayed neuropsychomotor development associated with degeneration of the central nervous system may lead the patient to progressive generalized muscular hypotonia, evolving into seizures and convulsive seizures. We report a case of male patient, presenting changes in neuropsychomotor devel- opment since eight months of age, with diagnostic elucidation through clinical exam, imaging and laboratory tests. Method: Search in digital databases for scientific articles that discuss gangliosidoses. Results/ conclusion: Gangliosidosis is rare disorder, which makes reporting an important source of research. (AU)

ANÁLISIS DE LA β -GALACTOSILCERAMIDASA LEUCOCITARIA EN PACIENTES COLOMBIANOS CON SOSPECHA CLÍNICA DE ENFERMEDAD DE KRABBE, UN TAMIZAJE DE ALTO RIESGO / ANALYSIS OF β -GALACTOSILCERAMIDASE LEUKOCYTAL IN COLOMBIAN IN PATIENTS WITH SUSPECT CLINIC OF KRABBE DISEASE, A HIGH - RISK SCREENING / ANÁLISE DE β -GALACTOSILCERAMIDASE LEUKOCYTAL EM COLOMBIANO EM PACIENTES COM SUSPEITA CLINICA DA DOENÇA DE KRABBE, UMA BLINDAGEM DE ALTO RISCO HUMANOS PLACENTA

La Enfermedad de Krabbe (EK), es un desorden del metabolismo de esfingolípidos de herencia autosómica recesiva causada por la deficiencia de β-galactosilceramidasa (β-Galsil) (E.C. 3.2.1.46), defecto enzimático que causa un cuadro neurodegenerativo, hipertonía muscular y espasticidad, convulsiones, pérdida de la audición y en un 85% de los casos la muerte temprana, entre otros hallazgos. La incidencia de la EK documentada para Estados Unidos y Europa es de 1:100.000 recién nacidos, pero estudios recientes han demostrado valores mayores de 1:22.000 aproximadamente en New York. En América Latina los informes son escasos, con reportes de tamizaje de alto riesgo en Brasil y casos aislados en México, ofreciendo un panorama de subdiagnóstico importante, situación a la que no es ajena Colombia, donde no hay en la literatura referentes a la enfermedad. Se presenta entonces a la comunidad científica, un estudio de valores de actividad y de referencia para la enzima β-Galactosilceramidasa leucocitaria, a partir de 259 muestras de 110 individuos sanos y 149 pacientes con compromiso neurodegenerativo (CND). La valoración enzimática involucró dos métodos (Colorimétrico y Fluorométrico) de punto final que permitieron establecer un rango de referencia para β-Galsil en técnica Colorimétrica: 2,04-14,93 nmol/mgprot/h y en técnica fluorométrica: 0,3-4,21 nmol/mgprot/h. El estudio de tamizaje permitió identificar un paciente afectado con enfermedad de Krabbe quien presentó valores de actividad expresados en nmol/mgprot/h de 1,85 y 0,034, en forma correspondiente para las técnicas antes descritas. Un hallazgo final que permite validar los dos métodos estandarizados para el diagnóstico de la enfermedad y establecer valores de referencia en población colombiana.

Krabbe disease is a disorder of autosomal recessive sphingolipid metabolism caused by deficiency β-galactosylceramidase (β-Galsil) (EC3.2.1.46), an enzymatic defect that causes a hurt neurodegenerative, muscular hypertonia and Spasticity, convulsions, hearing loss and in 85% of cases early death, among other findings. The incidence documented for "Krabbe disease" in the United States and Europe is 1:100.000 newborns, but recent studies have shown values greater than 1:22.000 in New York. In Latin America, reports are limited, with reports of high-risk screening in Brazil and isolated cases in Mexico, providing an important underdiagnosis scenario, a situation that is not unknown in Colombia, where there is no literature on the disease. A study of activity and reference values for β-galactosylceramidase enzyme leukocytal, was then presented to the scientific community, from 259 samples from 110 healthy people and 149 patients with neurodegenerative compromise. The enzymatic evaluation involved two methods (Colorimetric and Fluorometric) that allowed the establishment of a reference range for β-Galsil in Colorimetric technique: 2.04-14.93 nmol/mgprot/h and in fluorometric technique: 0.3-4.21 nmol/mgprot/h. The screening study allowed the identification of a patient with Krabbe disease who presented activity values expressed in nmol/mgprot/h of 1.85 and 0.034, correspondingly to the techniques described above. A final finding that allows to validate the two standardized methods for the diagnosis of the disease and to establish reference values in Colombian population.

A doença de Krabbe é uma desordem do metabolismo de esfingolípidos autossômicos recessivos causada pela deficiência β-galactosilceramidase (β-Galsil) (EC 3.2.1.46), um defeito enzimático que causa uma neurodegenerativa relatório, hipertonia muscular e espasticidade, convulsões, perda auditiva e em 85% Dos casos de morte precoce, entre outros. A incidência da doença de Krabbe documentado para os Estados Unidos e na Europa é de 1:100.000 recém-nascidos, mas estudos recentes têm mostrado valores maiores do que cerca de 1:22.000, em Nova York. Na América Latina, os relatórios são escassos, com relatos de rastreio de alto risco no Brasil e casos isolados no México, proporcionando um cenário importante subdiagnóstico, a situação não é desconhecida em que a Colômbia, não há literatura Onde sobre a doença. Um estudo de atividade e valores de referência para a enzima β-galactosilceramidase leucocital, foi então apresentado comunidade científica, de 259 amostras de 110 indivíduos saudáveis e​ 149 pacientes com comprometimento neurodegenerativo. A avaliação enzimática envolveu dois métodos (Colorimétrico e Fluorométrico) que permitiram o estabelecimento de uma gama de referência para β-Galsil na técnica Colorimétrica: 2,04-14,93 nmol /mgprot/h e na técnica fluorométrica: 0,3-4,21nmol/mgprot/h. O estudo de triagem permitiu a identificação de um paciente com doença de Krabbe que apresentou valores de atividade expressados ​em nmol / mgprot / h de 1,85 e 0,034, correspondente ao das técnicas descritas acima. Uma conclusão final que valida os dois métodos padronizados para o diagnóstico da doença e estabelecer valores de referência na população colombiano.

Asociación de melanocitosis dérmica con enfermedades lisosomales / Association of dermal melanocytosis with lysosomal storage diseases

Introducción: la melanocitosis dérmica incluye un espectro de lesiones de piel que abarca la mancha mongólica, entre otras lesiones. Las enfermedades lisosomales son afecciones de base genética que se caracterizan por la acumulación de metabolitos insolubles parciamente degradados en los compartimentos lisosomales, debido a una determinada deficiencia enzimática. Las deficiencias de b-galactosidasa y de a-L-iduronidasa provocan la gangliosidosis GM1 y la mucopolisacaridosis tipo I respectivamente, ambas presentando similitudes en su presentación clínica. La asociación de la melanocitosis dérmica con las enfermedades lisosomales es poco común y mal entendida. Objetivo: reportar dos pacientes con esta rara asociación. Casos clínicos: dos varones de 3 y 9 meses sin antecedentes prenatales ni perinatales a destacar y antecedentes de infecciones respiratorias reiteradas. Se presentaron con retraso del desarrollo, hipotonía central y trastorno deglutorio. Al examen se constató hepatomegalia, fascies tosca y melanosis dérmica extensa. Los estudios permitieron diagnosticar al paciente de 3 meses mucopolisacaridosis Tipo I y al de 9 meses gangliosidosis GM1. Discusión: no se conoce exactamente la causa de esta asociación. Se plantea que sería el resultado de la acumulación de gangliósidos y heparán sulfato que estimularían al receptor del factor de crecimiento neuronal de tipo tirosinquinasa, deteniendo la migración de los melanocitos en la dermis. Por lo tanto la melanosis dérmica aberrante, en el contexto clínico adecuado, puede ser un signo que facilite el diagnóstico de una enfermedad lisosomal subyacente.

Introduction: dermal melanocytosis includes a spectrum of skin lesions, mongolian spots being one of them. Lysosomal storage diseases are characterized by the accumulation of partially degraded insoluble metabolites in lysosomal compartments due to enzyme deficiency. Deficiency in b-galactosidosisis is the cause of GM1 gangliosidosis and deficiency in a-L-iduronidasa of mucopolysaccharidosis type I. Both have similar clinical presentations. Association of dermal melanocytosis and lysosomal storage diseases is uncommon and misunderstood. Objective: to report the case of two patients with this rare association. Clinical cases: the study presents two boys, 3 and 9 months old, with no remarkable family, pregnancy or delivery history. Both had repeated respiratory tract infections. They presented with developmental delay, central hypotonia and swallowing disorder. Upon clinical examination they showed hepatomegaly, coarse facies and extensive dermal melanocytosis. They were diagnosed with GM1 gangliosidosis and mucopolysaccharidosis type I. Discussion: the cause of this association is not well known. It is hypothesized that accumulation of gangliosides and heparan sulfates stimulates tyrosine-kinase neuronal growth factor receptor, stopping dermal melanocytosis migration. Therefore extensive dermal melanocytosis, in an appropriate clinical setting, may contribute to diagnosing lysosomal storage diseases.

Gangliosidosis generalizada tipo 1 / Generalized gangliosidosis type 1

La gangliosidosis generalizada tipo 1 es una enfermedad de acúmulo lisosomal producida por mutaciones en el gen de la enzima b-galactosidasa, caracterizada fundamentalmente por toma del sistema nervioso central, la visceromegalia, disostosis ósea y dimorfismo facial. Se presenta el caso de un lactante varón, hijo de padres no consanguíneos, de 5 meses de edad, Apgar 6/8 debido a hipoxia neonatal, con historia de múltiples ingresos por enfermedad diarreica e infecciones respiratorias. Es remitido a la Consulta de Genética Clínica por retardo del desarrollo psicomotor, macrocráneo y hepatomegalia, además de máculas hipercrómicas en piel. En el examen físico se encontraron evidencias de una posible afectación por enfermedad metabólica lisosomal. Entre las enfermedades a descartar estaban la galactosialidosis, de características clínicas similares, y la enfermedad de Morquio, con diferente presentación clínica pero idéntico defecto enzimático

Generalized or GM 1 gangliosidosis is a lysosomal storage disease caused by mutations in the enzyme b-galactosidase gene, mainly characterized by affecting the central nervous system, visceromegalia, osseous dysostosis and facial dimorphism. This is the case of a male nursling born to non-consanguineous parents, 5 months of age, Apgar index of 6/8 due to neonatal hypoxia, with a history of several admissions to hospital because of diarrheal disease and respiratory infections. He was referred to the clinical genetic service since he presented with retarded psychomotor development, macrocrania and hepatomegalia, in addition to hyperchromic skin spots. The physical exam found evidence of possible effects by lysosomal metabolic disease. Among the diseases to be ruled out for the diagnosis were galactosialidosis of similar clinical characteristics and Morquio B disease with different clinical presentation but identical enzymatic deficiency

Gangliosidosis 1 in brother and sister: case report

GM1 gangliosidosis is an autosomal recessive lysosomal storage disorder characterized by the generalized accumulation of GM1 ganglioside. Deficiency of the lysosomal hydrolase, acid beta-galactosidase, causes GM1 gangliosidosis and Morquio disease type B. 1, 2 Three clinical subtypes of GM1 gangliosidosis are recognized, classified by age of onset, [Infantile [type 1], juvenile [type 2] and adult [type 3][3, 4, 5]. We describe here 2 sibs brother and sister with features suggestive of GM 1 and confirm the diagnosis with enzymatic assay for beta galactosidase enzyme

Transient high-level expression of ß-galactosidase after transfection of fibroblasts from GM1 gangliosidosis patients with plasmid DNA

GM1 gangliosidosis is an autosomal recessive disorder caused by the deficiency of lysosomal acid hydrolase ß-galactosidase (ß-Gal). It is one of the most frequent lysosomal storage disorders in Brazil, with an estimated frequency of 1:17,000. The enzyme is secreted and can be captured by deficient cells and targeted to the lysosomes. There is no effective treatment for GM1 gangliosidosis. To determine the efficiency of an expression vector for correcting the genetic defect of GM1 gangliosidosis, we tested transfer of the ß-Gal gene (Glb1) to fibroblasts in culture using liposomes. ß-Gal cDNA was cloned into the expression vectors pSCTOP and pREP9. Transfection was performed using 4 µL lipofectamine 2000 and 1.5-2.0 µg DNA. Cells (2 x 10(5)/well) were harvested 24 h, 48 h, and 7 days after transfection. Enzyme specific activity was measured in cell lysate and supernatant by fluorometric assay. Twenty-four hours after transfection, treated cells showed a higher enzyme specific activity (pREP9-ß-Gal: 621.5 ± 323.0, pSCTOP-ß-Gal: 714.5 ± 349.5, pREP9-ß-Gal + pSCTOP-ß-Gal: 1859.0 ± 182.4, and pREP9-ß-Gal + pTRACER: 979.5 ± 254.9 nmol·h-1·mg-1 protein) compared to untreated cells (18.0 ± 3.1 for cell and 32.2 ± 22.2 nmol·h-1·mg-1 protein for supernatant). However, cells maintained in culture for 7 days showed values similar to those of untreated patients. In the present study, we were able to transfect primary patients' skin fibroblasts in culture using a non-viral vector which overexpresses the ß-Gal gene for 24 h. This is the first attempt to correct fibroblasts from patients with GM1 gangliosidosis by gene therapy using a non-viral vector.

IgM anti-GM1 antibody titers in patients with monomelic amyotrophy.

BACKGROUND: Monomelic amyotrophy (MMA) is a benign motor neuron disorder, which particularly affects young people and the etiology is still unknown. Gangliosides are located on the outer surface of motor neurons. Anti-GM1 antibodies have been found to be elevated in multi-focal motor neuropathy with conduction block and other neurological diseases, which may have therapeutic implication. AIM: To evaluate IgM anti-GM1 antibody titers in patients of monomelic amyotrophy. SETTING AND DESIGN: prospective controlled study. MATERIALS AND METHODS: Forty-six clinically and electrophysiologically diagnosed cases of MMA were assessed for IgM anti-GM1 antibody titers by enzyme-linked immunosorbent assay (ELISA) method and compared with titers in healthy controls, cases of amyotrophic lateral sclerosis (ALS) and acute inflammatory demyelinating polyneuropathy (AIDP). Titer of 800 units was taken as upper limit of normal (Buhlmann Laboratories AG, Switzerland). STATISTICAL ANALYSIS USED: one-way ANOVA. RESULTS: The mean age of 46 patients with MMA was 24.5 (+/- 7.3) years, with male female ratio of 44:2. The mean age of 19 healthy controls was 24.1 (+/- 3) years with male: female ratio of 18:1. Five (26%) individuals in the healthy control group, 22 (48%) patients of MMA, four (30%) of ALS and five (50%) of AIDP had high titers of IgM anti-GM1 antibody (P> 0.05). CONCLUSIONS: Although larger number of patients with MMA had higher IgM anti-GM1 antibody titers, the difference was not statistically significant from titers of healthy individuals and of patients in the ALS and AIDP group.

A Galactosialidosis Mimicking GM1-gangliosidosis Type I / 대한소아신경학회지

Galactosialidosis is a lysosomal storage disease associated with a combined deficiency of beta-galactosidase and alpha-neuraminidase, secondary to a defect of another lysosomal protective protein. It is a neurodegenerative disorder clinically characterized by psychomotor deterioration, cerebellar ataxia, coarse facies, generalized bony deformity and organomegaly. Three phenotypic subtype are recognized:early infantile, late infantile and juvenile/adult type. We report a 13 months old boy with a late infantile galactosialidosis. He was presented with progressive mental regression and motor disturbance and observed cherry red spot, hearing loss, moderate dysostosis multiplex and vacuolated lymphocytes in peripheral blood. He showed only beta-galactosidase deficiency in the lymphocytes and was diagnosed as GM1-gangliosidosis type 1. However, further studies revealed the possible defect of alpha-neuraminidase suggesting that he was a case of galactosialidosis which was mimicking GM1-gangliosidosis type 1.

Sphingolipidoses / 한양의대학술지

Sphingolipidoses are a subgroup of lysosomal storage disorders. They are characterized by relentless progressive storage in affected organs and concomitant functional impairments. No overall screening procedure for these disorders is available. Their course and appearance, however, are usually characteristic and, together with relevant technical procedures such as magnetic resonance imaging (MRI), clinical neurophysiology, ophthalmologic examination, etc., a provisional diagnosis can be made, after which enzymatic diagnosis can close the gap in the diagnostic process. Subgroups of sphingolipidoses are grouped together, such as disorders with prominent hepatosplenomegaly (Niemann-Pick A, B and Gaucher disease) and disorders with central and peripheral demyelination (metachromic leukodystrophy and Krabbe disease). Farber disease and Fabry disease are unique in themselves. The last decade has seen hopeful progress in therapeutic strategies, especially for Gaucher disease. Therefore, emphasis of this review has been placed on these new developments.

Lysosomal storage disorders in Thailand: the Siriraj experience.

Lysosomal storage disorders are a heterogeneous group of biochemical genetic disorders; currently 40-50 are known. The clinical phenotype is determined by the tissue distribution of the storage material and degree of enzyme deficiency. The genetic transmission is mostly autosomal recessive. Lysosomal storage disorders can be divided into three groups according to the major organ system pathology: (1) Primary involvement of the central nervous system without significant somatic or skeletal pathology. Disorders of grey matter, eg gangliosidosis and disorders of white matter eg the leucodystrophy are the most common; (2) Primary involvement of the reticuloendothelial system with or without associated neuropathology, eg Niemann-Pick disease and Gaucher disease; (3) Multisystem involvement in which skeletal manifestations are prominent features. The mucopolysaccharidosis and mucolipidoses are the two major forms with this clinical phenotype. Lysosomal storage disorders identified at Siriraj Hospital are neuronal ceroid lipofuscinosis, GMI gangliosidosis, mucolipidosis II, Maroteaux-Lamy, sialidosis, Sly syndrome, Hunter syndrome, Morquio syndrome, Gaucher disease, Niemann-Pick, Sandhoff disease, Pompe's disease and many more. Most patients came from the provinces where consanguinity is common. Confirmation usually is done by enzyme assays using skin fibroblast culture or leucocytes. Genetic counseling is extremely important and prenatal diagnosis is recommended to high-risk couple.