Tumores renales pediátricos y su posible asociación con poblaciones endogámicas en el centro de Argentina / Pediatric renal tumors and their possible relation with endogamous populations in central Argentina

Introducción: Existen pocas investigaciones sobre factores de riesgo de tumores renales pediátricos. Objetivo: Caracterizar en detalle regiones geográficas de alta incidencia de tumores renales pediátricos en el centro de Argentina y su posible vinculación con factores de riesgo genéticos. Métodos: El área de estudio comprendió la provincia de Córdoba (Argentina). Se generó una base de datos de incidencia del cáncer renal infantil con información del Registro Provincial de Tumores. Se realizaron análisis de conglomerados espaciotemporales. En localidades dentro de los conglomerados, se llevaron a cabo entrevistas en profundidad a informantes claves. Resultados: Se registraron 56 casos de tumores renales pediátricos en el Registro en el periodo 2004-2013. Se detectó un conglomerado espacial significativo que abarca siete departamentos de la provincia. En esa región se concretaron seis entrevistas en profundidad a informantes claves. Los entrevistados resaltaron la mayor frecuencia de enfermedad genética de Sandhoff y las prácticas de endogamia (corroboradas en numerosos resultados científicos). A partir de estos datos se determinaron zonas de superposición de tumores renales y de la enfermedad de Sandhoff. Conclusiones: Se detectó una región particular de la provincia con alta frecuencia de tumores renales pediátricos y de la enfermedad de Sandhoff. Numerosos estudios científicos determinan que la endogamia es el factor de riesgo que aumenta la frecuencia de esta enfermedad en esta región. En futuras investigaciones se deberá corroborar si la endogamia también actúa aumentando la incidencia de tumores renales infantiles(AU)

Introduction: There is little research on risk factors of pediatric renal tumors. Objective: To characterize in detail the geographic regions of greatest incidence of pediatric renal tumors in central Argentina and exploring their possible link to genetic risk factors. Methods: The study area comprised the province of Córdoba (Argentina), and a database of pediatric renal tumors incidence was generated with information from the Provincial Tumor Registry. Analyses of spatio-temporal clusters were performed. In-depth interviews with key informants were carried out at localities within the conglomerates. Results: 56 cases of pediatric renal tumors were registered in the Provincial Registry of Tumors between 2004 and 2013. A significant spatial conglomerate was detected, covering seven districts of the province. In that region, six in-depth interviews were conducted with key informants. Interviewees highlighted the increased frequency of Sandhoff genetic disease and endogamous practices (corroborated in numerous scientific results). From these data, zones of overlap of renal tumors and of Sandhoff disease were determined. Conclusions: A particular region of the province was detected with high frequency of pediatric renal tumors and Sandhoff disease. Numerous scientific studies have determined that endogamy is the risk factor that increases the frequency of Sandhoff disease in this region. In future research, it should be confirmed whether it also acts by increasing the incidence of renal tumors in children(AU)

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.

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.

Infantile Sandhoff disease:a case report and literature review / 临床儿科杂志

Objective To summarize the clinical manifestations, diagnosis, and treatment of infantile Sandhoff disease. Methods The clinical data of one case with infantile Sandhoff disease were reviewed retrospectively. The related literatures were reviewed. Results The girl aged 1 year and 2 months suffered from psychomotor regression and intractable convulsions. The parents were consanguineous marriage. The fundus microscopy showed fundus erythema. Brain magnetic resonance imaging showed an abnormal signal of long T2WI and identical T1WI at left pons, white matter edema, and diffuse demyelination. No abnormal karyotype was observed. A chromosome microarray suggested multiple large homozygous chromosomes segments. The second generation gene sequencing showed deletion of c.1263_1268delTGAAGT:P. (Glu422_Val423del) deletion in exon 11 and a shear mutation of c.1614_2A>G:P? in intron 13 of HEXB gene which were carried by her parents respectively . The activity of HexA, HexA & HexB were 84 and 112 nmol?mg?1?h?1, respectively. Finally, this girl was diagnosed of infantile Sandhoff's disease. After treatment with valproate, levetiracetam combined with antiepileptic and glucocorticoids, episodes of convulsions were decreased gradually, and the reaction was better than before. In 5 months of follow up, the condition was stable, and no progression and no seizures exist. Her mother got pregnant again and received an amniocentesis on her 21+6 weeks of pregnancy, and results suggest that the fetus had the same mutation as this girl. Conclusions Sandhoff's disease is a type of rare hereditary lysosomal disease, characterized by progressive neurological impairment. Currently there are no effective treatments. Genetic testing is helpful in the diagnosis and prenatal diagnosis.

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.

Characterization of recombinant human lysosomal beta-hexosaminidases produced in the methylotrophic yeast Pichia pastoris / Caracterización de beta-hexosaminidasas lisosomales humanas recombinantes producidas en la levadura metilotrófica Pichia pastoris / Caracterização de beta-hexosaminidases lisossomais humanas recombinantes produzidas na levedura metilotrófica Pichia pastoris

Abstract β-hexosaminidases (Hex) are dimeric enzymes involved in the lysosomal degradation of glycolipids and glycans. They are formed by α- and/or β-subunits encoded by HEXA and HEXB genes, respectively. Mutations in these genes lead to Tay Sachs or Sandhoff diseases, which are neurodegenerative disorders caused by the accumulation of non-degraded glycolipids. Although tissue-derived Hex have been widely characterized, limited information is available for recombinant α-hexosaminidases. In this study, human lysosomal recombinant Hex (rhHex-A, rhHex-B, and rhHex-S) were produced in the methylotrophic yeast Pichia pastoris GS115. The highest specific enzyme activities were 13,124 for rhHexA; 12,779 for rhHex-B; and 14,606 U .mg-1 for rhHex-S. These results were 25- to 50-fold higher than those obtained from normal human leukocytes. Proteins were purified and characterized at different pH and temperature conditions. All proteins were stable at acidic pH, and at 4 °C and 37 °C. At 45 °C rhHex-S was completely inactivated, while rhHex-A and rhHex-B showed high stability. This study demonstrates P. pastoris GS115 potential for polymeric lysosomal enzyme production, and describes the characterization of recombinant β-hexosaminidases produced within the same host.

Resumen Las β-hexosaminidasas (Hex) son enzimas diméricas involucradas en la degradación lisosomal de glicolípidos y glicanos. Estas enzimas están formadas por las subunidades α- y/o β-codificadas por los genes HEXA and HEXB respectivamente. Las mutaciones de estos genes conducen a las enfermedades de Tay Sachs o Sandhoff, que son desórdenes neurodegenerativos causados por la acumulación de glicolípidos no degradados. Aunque las Hex derivadas de tejido han sido ampliamente caracterizadas, la información disponible sobre las p-hexosaminidasas recombinantes es limitada. En este estudio se produjeron Hex recombinantes lisosomales (rhHex-A, rhHex-B y rhHex-S) en la levadura metilotrófica Pichia pastoris GS115. Las actividades específicas más altas de las enzimas fueron 13.124, 12.779, 14.606 U .mg-1 para rhHex-A, rhHex-B y rhHex-S, respectivamente. Estos resultados fueron 25 a 50 veces más altos que los obtenidos de leucocitos humanos normales. Las proteínas se purificaron y se caracterizaron a diferentes condiciones de pH y temperatura. Todas las proteínas fueron estables a pH ácido y a 4°C y 37°C. A 45°C la rhHex-S se inactivó completamente, mientras que rhHex-A y rhHex-B mostraron alta estabilidad. Este estudio demuestra el potencial de P. pastoris GS115 para la producción de enzimas lisosomales poliméricas y presenta la caracterización de distintas β-hexosaminidasas recombinantes producidas en un único hospedero.

Resumen As β-hexosaminidases (Hex) são enzimas diméricas envolvidas na degradação lisossomal de glicolipídeos e glicanos. Essas enzimas são formadas por subunidades a- e/ou p-codificadas pelos genes HEXA e HEXB, respectivamente. As mutações nesses genes causam a doença de Sandhoff ou Tay Sachs, que são desordens neurodegenerativas causadas pela acumulação de glicolipídeos não degradados. Embora Hex derivadas de tecido hajam sido caracterizadas extensivamente, as informações disponíveis sobre as p-hexosaminidases recombinantes são limitadas. Esse estudo produziu Hex recombinantes lisossomais (rhHex-A, rhHex-B e rhHex-S) na levedura metilotrófica Pichia pastoris GS115. As atividades específicas mais altas das enzimas foram 13.124, 12.779, 14.606 U .mg-1 para rhHex-A, rhHex-B y rhHex-S, respectivamente. Esses resultados foram 25 a 50 vezes mais altos do que os obtidos a partir de leucócitos humanos normais. As proteínas foram purificadas e caracterizadas em diferentes condições de pH e temperatura. Todas as proteínas foram estáveis a pH ácido e a 4°C e 37°C. A 45°C a rhHex-S foi completamente inativada, enquanto rhHex rhHex-A e B se mostraram altamente estáveis. Esse estudo demonstra o potencial de P. pastoris GS115 para a produção de enzimas lisossomais poliméricas e apresenta a caracterização de diferentes p-hexosaminidases recombinantes produzidas em único hospedeiro.

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.