Analysis of HEXB gene mutations in an infant with Sandhoff disease / 中华医学遗传学杂志

OBJECTIVE@#To detect potential mutations of HEXB gene in an infant with Sandhoff disease (SD).@*METHODS@#Genomic DNA was extracted from peripheral blood sample of the infant. All coding exons (exons 1 to 14) and splicing sites of the HEXB gene were subjected to PCR amplification and direct sequencing.PubMed Protein BLAST system was employed to analyze cross-species conservation of the mutant amino acid. PubMed BLAST CD-search was performed to identify functional domains destroyed by thecandidate mutations. Impact of the mutations was analyzed with software including PolyPhen-2, Mutation Taster and SIFT. Whole-exome sequencing was carried out to identify additional mutations.@*RESULTS@#The infant was found to carry compound heterozygous mutations c.1652G>A(p.Cys551Tyr) and c.1389C>G (p.Tyr463*) of the HEXB gene. The c.1389C>G (p.Tyr463*) mutation may lead to destruction of two functional domains in β subunit of the Hex protein. The c.1652G>A(p.Cys551Tyr) mutation, unreported previously,was predicted to be probably damaging by Bioinformatic analysis.@*CONCLUSION@#Compound heterozygous mutations c.1652G>A(p.Cys551Tyr) and c.1389C>G (p.Tyr463*) in the HEXB gene probably underlie the disease in this patient.

Marcapasos con sensor de asa cerrada en disautonomía secundaria a enfermedad de Sandhoff / Closed-loop pacemakers in dysautonomia secondary to Sandhoff disease

Resumen Introducción: en la enfermedad de Sandhoff se ha descrito el compromiso del sistema nervioso autónomo en piel y tracto gastrointestinal; sin embargo, las alteraciones autonómicas del sistema cardiovascular, como la disautonomía, no se han documentado en la literatura revisada. De otro lado, el síncope neuralmente mediado de características cardioinhibitorias, refractario al manejo médico, puede ser tratado con marcapasos con sensor de asa cerrada. Materiales y métodos: se describe el caso de una paciente de 42 años en quien se realizó el diagnóstico de enfermedad de Sandhof. Asociado a esta patología, presentó disautonomía con episodios de síncope diarios sin respuesta al tratamiento médico, que ameritaron el implante de un marcapasos con sensor de asa cerrada. Posteriormente se revisa la literatura existente sobre el tema. Conclusiones: hasta la fecha no se había reportado relación entre la enfermedad de Sandhoff y la disautonomía; en el caso de esta paciente el deterioro de la calidad de vida fue significativo. El uso del algoritmo CLS en síncope neuralmente mediado con características cardioinhibitorias, ha mostrado disminuir la cantidad de síncopes en este tipo de pacientes y mejorar la calidad de vida de los mismos.

Abstract Introduction: Although involvement of the autonomic nervous system in the skin and gastrointestinal tract has been described in Sandhoff disease, no reports of autonomic changes of the cardiovascular system, such as dysautonomia, have been documented in the literature reviewed. On the other hand, the neurally mediated cardioinhibitory syncope that is refractory to medical management can be treated with pacemakers with closed loop sensors. Materials and methods: The case is described of a 42 year-old patient who was diagnosed with Sandhoff disease. Associated to this condition, he presented with dysautonomia with daily episodes of syncope, with no response to medical treatment, which warranted the implant of a pacemaker with a closed loop sensor. The existing literature on this topic was subsequently reviewed. Conclusions: Up until now, there have been no reports on the relationship between Sandhoff disease and dysautonomia. In the case of this patient, the deterioration in the quality of life was significant. The use of the closed loop stimulation (CLS) algorithm in neurally mediated cardioinhibitory syncope has been shown to reduce the number of syncopes in this type of patient and improve their quality of life.

Variante juvenil de la enfermedad de Sandhoff: presentación del primer caso descrito en Argentina / Juvenile form of Sandhoff disease: first case reported in Argentina

La enfermedad de Sandhoff es una patología neurodegenerativa, de almacenamiento lisosomal, causada por mutaciones en el gen HEXB. Existen tres formas clínicas: infantil, juvenil y adulta. Previamente, fue identificada una población endogámica en la provincia de Córdoba, Argentina, que presentaba una alta incidencia de la enfermedad; todos los casos correspondieron a la forma infantil. En este trabajo, se presenta por primera vez el caso de un paciente argentino con la variante juvenil de la enfermedad de Sandhoff. El paciente es un niño de 7 años que, a partir de los 2, presentó ataxia, trastorno del habla y retraso global en el desarrollo. El diagnóstico se confirmó con la detección de valores residuales de enzima hexosaminidasa y con la identificación de dos mutaciones ya descritas en estado de heterocigosis: c.796T>G (p.Y266D) y c.1615C>T (p.R539C).

Sandhoff disease is a neurodegenerative, lysosomal and autosomal recessive disease caused by mutations in the HEXB gene. Three forms are recognized: infantile, juvenile and adult. Previously, an endogamous population in Córdoba, Argentina, was identified with a high incidence of Sandhoff disease, all reported cases were of the infantile type. In this work, we describe a child with the juvenile form of Sandhoff disease, the first case reported in Argentina. The patient is a 7-year-old boy presenting with ataxia, speech disturbances and global developmental delay, symptoms starting at the age of 2 years. Diagnosis was based on the hexosaminidase deficiency. Sequencing of genomic DNA revealed compound heterozygosity for two HEXB gene mutations: c.796T>G (p.Y266D) and c.1615C>T (p.R539C), both already reported.

An Infantile Case of Sandhoff Disease Presenting With Swallowing Difficulty

Infants with Sandhoff disease typically appear normal until 3–6 months of age. As the disease progresses, they present with symptoms such as loss of motor skills, exaggerated startle response to loud noise, seizures, visual loss, and paralysis. We encountered a rare case of a 22-month-old girl with Sandhoff disease characterized by progressive motor weakness and dysphagia, who initially showed signs of aspiration at 20 months of age. The major problems related to dysphagia were oromotor dysfunction and abnormal feeding posture. Within 3 months of identification of difficulty in swallowing, the patient showed a significant decrease in food intake, with rapid deterioration of nutritional status. We report our case with a review of the literature.

Clinical and molecular characteristics of a child with juvenile Sandhoff disease / 中华儿科杂志

<p><b>OBJECTIVE</b>To explore the clinical features and molecular mutation of HEXB gene in a case with juvenile Sandhoff disease.</p><p><b>METHOD</b>We retrospectively reviewed the clinical, neuroimaging and biochemical findings in this Chinese child with juvenile Sandhoff disease. Hexosaminidase A and hexosaminidase A & B activities were measured in blood leukocytes by fluorometric assay. HEXB gene molecular analysis was performed by PCR and direct sequencing.</p><p><b>RESULT</b>The 9-year-old boy was admitted for psychomotor regression. He presented slowly progressive gait disorder and dysarthria during the last three years. Cranial MRI revealed a marked cerebellar atrophy with normal intensity in the thalamus and basal ganglia. Brain MRS showed normal in the thalamus and basal ganglia. Hexosaminidase A was 69.5 (mg·h) [normal controls 150-360 nmol/(mg·h)], hexosaminidase A & B activity was 119 nmol/(mg·h)[normal controls 600-3 500 nmol/(mg·h)], confirming the diagnosis of Sandhoff disease. The patient was a compound heterozygote for a novel deletion mutation c.1404delT (p. P468P fsX62) and a reported mutation c.1509-26G>A.</p><p><b>CONCLUSION</b>The clinical features of juvenile Sandhoff disease include ataxia, dysarthria and cerebellar atrophy. The enzyme assay and molecular analysis of HEXB gene can confirm the diagnosis of Sandhoff disease. The novel mutation c.1404delT(p. P468P fsX62) is a disease-related mutation.</p>

HEXB gene study and prenatal diagnosis for a family affected by infantile Sandhoff disease / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the phenotype and genotype of a Chinese boy and his family affected by infantile Sandhoff disease.</p><p><b>METHODS</b>The proband, a boy, was the first child born to a non-consanguineous couple. He showed startle reaction after birth and progressive psychomotor regression from the age of 8 months. From the age of 16 months, he presented seizures. When he was admitted at 17 months old, severe mental retardation and weakness were observed. Fundus examination revealed bilateral cherry-red spots in the macula and optic atrophy. Cranial MRI revealed abnormal signals in the thalamus, basal ganglia and white matter. Enzymatic assay and genetic testing were performed for the diagnosis. His mother visited us at 18 weeks of pregnancy seeking for prenatal diagnosis. HEXB gene diagnosis to the fetus was performed by direct sequencing.</p><p><b>RESULTS</b>Significant deficient total β-hexosaminidase (A and B) activity in peripheral leucocytes of the patient (0.0 nmol/h/mg compared with normal control, 41.9 to 135.1 nmol/h/mg) supported the diagnosis of Sandhoff disease. On his HEXB gene, two mutations were found. c.1645G-A (p.G549R) was novel. c.IVS7-48T was a reported mutation. Now, the patient was 2 years and 3 months old, with progressive general failure, severe epilepsy, blindness and hypermyotonia. Subsequently, the mother visited us at 18 weeks of pregnancy seeking for prenatal diagnosis. HEXB gene analysis of the amniocytes was performed by direct sequencing. Both of the two mutations were not detected from cultured amniocytes. The result revealed that the fetus was not affected by Sandhoff disease. A healthy girl, the sibling of the proband, was born in term. Postnatal enzyme analysis and genetic analysis of the cord blood cells confirmed the prenatal diagnosis.</p><p><b>CONCLUSION</b>One novel mutation on HEXB gene was identified. Prenatal diagnosis to the fetus of this family was performed by amniocytes gene analysis.</p>

A Case Refort of Sandhoff Disease

Sandhoff disease is a rare autosomal recessive metabolic disease presenting bilateral optic atrophy and a cherry red spot in the macula. This case report presents the characteristics of a patient with Sandhoff disease as assessed by ophthalmic, neuroimaging, and laboratory procedures. Ophthalmologic examination revealed that the patient could not fixate her eyes on objects nor follow moving targets. A pale optic disc and a cherry red spot in the macula were seen in both eyes. Low signal intensity at the thalamus and high signal intensity at the cerebral white matter were noted in a T2-weighted brain MR image. A lysosomal enzyme assay using fibroblasts showed the marked reduction of both total beta-hexosaminidases, A and B. Based on the above clinical manifestations and laboratory findings, we diagnosed the patient as having Sandhoff disease.

Doença de Sandhoff / Disease Sandhoff

Objetivo: Apresentar um caso raro de Doença de Sandhoff em criança de meses de idade. Local: Hospital Guilherme Álvaro, Santos - São Paulo. Método: Diagnosticado pelo Fundo de Olho pela "Mácula em Cereja" e pedido enzimas para diferenciar da Doença de tay-Sachs e estudo multiclínico pela Neuropediatria e Pediatria. Resultado: A associação dos achados fundoscópicos, clínicos e das enzimas hexosamidases A e B direcionaram para o diagnóstico. Conclusão: O exame acurado do Fundo de Olho foi direcionador diagnóstico da Doença de Sandhoff.

GM2 gangliosidoses: a review of cases confirmed by beta-N-acetylhexosaminidase assay.

The inborn errors of GM2 ganglioside metabolism cause GM2 ganglioside to accumulate within the lysosomes of the nerve cells. The majority of the patients are infants with the Tay-Sachs form of the disease associated with a severe deficiency of beta-N-Acetylhexosaminidase A (hexosaminidase A). Both Hexosaminidase A and B are deficient in Sandhoff disease. The serum total hexosaminidase and the percentage of hexosaminidase A and B were estimated in 449 patients who presented with progressive mental-motor retardation. Three cases of Tay-Sachs disease and two cases of Sandhoff disease were detected. They presented with exaggerated startle response to acoustic stimuli, seizures, optic atrophy and retinal cherry red spots in addition to psychomotor retardation. One case of Sandhoff disease had hepatosplenomegaly and skeletal deformities.

Enzyme studies in GM2 gangliosidiosis, and their application in prenatal diagnosis.

Assay of hexosaminidase A and B enzymes in four cases with developmental regression and cherry red spot on fundus examination confirmed that three cases had Tay-Sachs disease, and one case had Sandhoff disease. Prenatal diagnosis was carried out by hexosaminidase enzyme assay in amniotic fluid and cells in one family, and chorionic villus sample in the second family. The fetus was diagnosed to be unaffected in one, and affected in the other family. Assay of hexosaminidase A and B is useful for specific diagnosis of GM2 gangliosidosis, and for prenatal diagnosis to reduce the burden of these disorders.

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.

Estimación de la frecuencia de heterocigotes de la enfermedad de Sandhoff en una población Argentina de alto riesgo: asignación predictiva del genotipo mediante un análisis estadístico / Estimation of the frecuency of heterozygotes in Sandhoff disease in an Argentine population of high risk: predictive assignment of the genotype through a statistical analysis

En trabajos preliminares hemos evidenciado una alta frecuencia de la Enfermedad de Sandhoff (ES), deficiencia génica de la actividad hidrolítica de la hexosaminidasa (Hex) en sus dos mayores isoenzimas Hex A y Hex B, en niños criollos de un semi-aislado geográfico de la Argentina. La presente comunicación se refiere a la estimación de la proporción de portadores del gen anormal entre 1400 escolares de la zona mediante la determinación con sustratos artificiales de la Hex Total y Hex B Sérica. Los valores de las actividades enzimáticas de 32 heterocigotos testigos, 15 de ellos obligados (padres), sirvieron de patrón de referencia autóctono para la detección de 71 heterocigotos de la muestra problema (4,93%). Los límites de confidencia del 99% determinaron que la proporción de los heterocigotos en la población estaba en el intervalo 0,0346-0,0636 o sea 1 portador por cada 16 a 29 habitantes de la región, resultado similar a la heterocigosis calculada según la ley de Hardy-Weinberg (1:14 a 1:26). El análisis estadístico de las dos variables empleadas (Hex Total y Hex B) de los subgrupos referenciales homocigotos normales y heterocigotos testigos, permitió la elaboración de una función discriminante cuadrática (FDC) capaz de discernir, con alta probabilidad, entre un genotipo mutado y otro normal. Los datos obtenidos indican una heterocigosis de ES exepcionalmente alta en la población de riesgo y coherente con la frecuencia de homocigotos enfermos reconocidos, otorgándose fundamento a un programa preventivo a nivel regional. Entre tanto, la FDC elaborada provee un recurso eficaz y práctivo de asesoramiento individual, sobre todo en el ámbito clínico vinculado al problema

Gangliosidosis Gm2 por deficiencia de hexosaminidasas A y B: a propósito de un caso / Hexosaminidase A and B deficiency, Gm2 gangliosidoses: apropos of a case

Se describe un paciente masculino de 26 meses de edad, hijo de padres no consanguíneos y quien presentó manifestaciones clínicas, bioquímicas e histopatológicas compatibles con la enfermedad de Sandhoff. Con fines de asesoramiento genético, se discuten las bases genéticas y moleculares que sustentan el diagnóstico diferencial con otras gangliosidosis Gm2

Gangliosidosis GM2 tipo 2: enfermedad de Sandhoff / Gangliosidosis GM2 type 2: Sandhoff's disease

Se estudió a un niño de 19 meses de edad con un cuadro clínico sugestivo de gangliosidosis GM2: facies peculiar, retardo psicomotor severo, espasticidad generalizada, crisis convulsivas tónicas, macrocefalia, pérdida de la función visual y auditiva, reflejos osteotendinosos exaltados y primer dedo de ambos pies en flexión sostenida; manchas rojo cereza en fondo de ojo y atrofia cerebral demostrada por EEG y TAC. Mediante cromatografía de capa fina se identificaron oligosacáridos en diferentes muestras de orina con un patrón cromatográfico característico. La actividad de las hexosaminidasas A y B en el paciente y sus padre fueron compatibles con homocigocidad y heterocigocidad respectivamente, para la deficiencia de ambas enzimas. Estos resultados permitieron precisar el diagnóstico de gangliosidosis GM2 tipo 2 (Enfermedad de Sandhoff). Se señala la importancia de la identificación de la oligosacariduria