Browsing by Author "Toro, Jessica"

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    Búsqueda de afecciones genéticas como etiología de déficit intelectual en individuos que asisten a escuelas de educación especial
    (Sociedad Médica de Santiago, 2008) Alliende, María Angélica; Campora, Laura; Curotto, Bianca; Toro, Jessica; Valiente, Alf; Castillo, Marcela; Cortés, Fanny; Trigo, César; Alvarado, Cecilia; Silva, Manuel; Caru, Margarita
    Background: Mental retardation or intellectual disability affects 2% ofthe general population, but in 60% to 70% of cases the real cause ofthis retardation is not known. An early etiologic diagnosis of intellectual disability can lead to opportunities for improved educational interventions, reinforcing weak areas and providing a genetic counseling to the family Aim: To search genetic diseases underíying intellectual disabilities of children attending a special education school. Material and methods: A clinical geneticist performed the history and physical examination in one hundred and three students aged between 5 and 24 years (51 males). A blood sample was obtained in 92 of them for a genetic screening that included a standard karyotype, fragile X molecular genetic testing and search for inborn errors of metabolism by tándem mass spectrometry. Results: This approach yielded an etiological diagnosis in as much as 29 patients. Three percent of them had a fragile X syndrome. Inborn errors of metabolism were not detected. Conclusions: This type of screening should be done always in children with intellectual disability to establish an etiological diagnosis.
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    Distinct Driver Pathway Enrichments and a High Prevalence of TSC2 Mutations in Right Colon Cancer in Chile: A Preliminary Comparative Analysis
    (2024) Tapia, Camilo; Valenzuela, Guillermo; González, Evelin; Maureira, Ignacio; Toro, Jessica; Freire, Matías; Sepúlveda, Gonzalo; Ampuero, Diego; Blanco, Alejandro; Gallegos, Iván; Morales, Fernanda; Erices, José; Barajas, Olga; Ahumada, Mónica; Contreras, Héctor; González, Jaime; Armisén, Ricardo; Marcelain, Katherine
    Colorectal cancer (CRC) is the second leading cause of cancer deaths globally. While ethnic differences in driver gene mutations have been documented, the South American population remains understudied at the genomic level, despite facing a rising burden of CRC. We analyzed tumors of 40 Chilean CRC patients (Chp) using next-generation sequencing and compared them to data from mainly Caucasian cohorts (TCGA and MSK-IMPACT). We identified 388 mutations in 96 out of 135 genes, with TP53 (45%), KRAS (30%), PIK3CA (22.5%), ATM (20%), and POLE (20%) being the most frequently mutated. TSC2 mutations were associated with right colon cancer (44.44% in RCRC vs. 6.45% in LCRC, p-value = 0.016), and overall frequency was higher compared to TCGA (p-value = 1.847 × 10-5) and MSK-IMPACT cohorts (p-value = 3.062 × 10-2). Limited sample size restricts definitive conclusions, but our data suggest potential differences in driver mutations for Chilean patients, being that the RTK-RAS oncogenic pathway is less affected and the PI3K pathway is more altered in Chp compared to TCGA (45% vs. 25.56%, respectively). The prevalence of actionable pathways and driver mutations can guide therapeutic choices, but can also impact treatment effectiveness. Thus, these findings warrant further investigation in larger Chilean cohorts to confirm these initial observations. Understanding population-specific driver mutations can guide the development of precision medicine programs for CRC patients.
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    Validation of an NGS Panel Designed for Detection of Actionable Mutations in Tumors Common in Latin America
    (2021) Salvo, Mauricio; González‐Feliú, Evelin; Toro, Jessica; Gallegos, Iván; Maureira, Ignacio; Miranda‐González, Nicolás; Barajas, Olga; Bustamante, Eva; Ahumada, Mónica; Colombo, Alicia; Armisén, Ricardo; Villamán, Camilo; Ibáñez, Carolina; Bravo, María Loreto; Sanhueza, Verónica; Spencer, M. Loreto; Toro, Gonzalo de; Morales, Erik; Bizama, Carolina; García, Patricia; Carrasco, Ana María; Gutiérrez, Lorena; Bermejo, Justo Lorenzo; Verdugo, Ricardo A.; Marcelain, Katherine
    Next‐generation sequencing (NGS) is progressively being used in clinical practice. How‐ ever, several barriers preclude using this technology for precision oncology in most Latin American countries. To overcome some of these barriers, we have designed a 25‐gene panel that contains pre‐ dictive biomarkers for most current and near‐future available therapies in Chile and Latin America. Library preparation was optimized to account for low DNA integrity observed in formalin‐fixed paraffin‐embedded tissue. The workflow includes an automated bioinformatic pipeline that ac‐ counts for the underrepresentation of Latin Americans in genome databases. The panel detected small insertions, deletions, and single nucleotide variants down to allelic frequencies of 0.05 with high sensitivity, specificity, and reproducibility. The workflow was validated in 272 clinical samples from several solid tumor types, including gallbladder (GBC). More than 50 biomarkers were de‐ tected in these samples, mainly in BRCA1/2, KRAS, and PIK3CA genes. In GBC, biomarkers for PARP, EGFR, PIK3CA, mTOR, and Hedgehog signaling inhibitors were found. Thus, this small NGS panel is an accurate and sensitive method that may constitute a more cost‐efficient alternative to multiple non‐NGS assays and costly, large NGS panels. This kind of streamlined assay with au‐ tomated bioinformatics analysis may facilitate the implementation of precision medicine in Latin America.

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