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Author: search.filters.author.Rafael Tamayo-TrujilloSubject: search.filters.subject.genomics

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    Item type:Publication,
    Neurofibromatosis Type 1 in Ecuador: genotype-phenotype correlations from a case series
    (Medwave Estudios Limitada, 2026-01-14)
    Elius Paz-Cruz
    ;
    Patricia Guevara-Ramirez
    ;
    Arianne Llamos Paneque
    ;
    Emily Onofre
    ;
    Christian Rivas Iglesias
    INTRODUCTION Neurofibromatosis type 1 (NF1) is a multisystemic genetic disorder caused by pathogenic variants in the NF1 gene, characterized by variable clinical manifestations such as pigmentary abnormalities, neurofibromas, skeletal dysplasia, and tumor predisposition. However, genotype-phenotype correlations remain insufficiently explored, particularly in underrepresented populations. METHODS Three unrelated Ecuadorian pediatric patients with a presumptive diagnosis of NF1 underwent detailed clinical evaluation, next-generation sequencing (NGS), using the TruSight Cancer panel, and ancestry analysis based on 46 ancestry-informative insertion-deletion (InDel) markers. Variants were classified according to ACMG/AMP guidelines using the Franklin and Variant Interpreter platforms, which incorporate in silico prediction tools to assess variant pathogenicity. RESULTS Three distinct pathogenic NF1 variants were identified: one nonsense (p.Arg1534Ter) and two missense (p.Gln20His, p.Asp1644Asn). Clinical findings included early-onset orbital plexiform neurofibroma, multiple café-au-lait macules, axillary/inguinal freckling, radial bone dysplasia, cutaneous neurofibromas, and prepubertal gynecomastia. All patients exhibited predominantly Native American ancestry. In silico analyses predicted a pathogenic classification of all variants. Early pigmentary signs, present in all cases, served as key diagnostic indicators. CONCLUSIONS This case series expands the mutational and phenotypic spectrum of NF1 in a pediatric Ecuadorian cohort. Findings underscore the diagnostic value of early pigmentary signs and highlight less commonly reported manifestations such as radial bone dysplasia and prepubertal gynecomastia. Integrating molecular diagnostics with early clinical evaluation may enable earlier and more precise diagnosis, guiding personalized management strategies. Further studies should investigate genotype-phenotype correlations and the influence of ancestry on NF1 expression.
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    Identification of a novel NKX2-5 variant in a young Ecuadorian patient with atrioventricular block and bradycardia: a case report
    (Frontiers Media SA, 2025-04-03)
    Ruiz Pozo Viviana A.  
    ;
    CADENA ULLAURI, SANTIAGO ANDRE  
    ;
    PAZ CRUZ, ELIUS ANDRES  
    ;
    Rafael Tamayo-Trujillo
    ;
    GUEVARA RAMIREZ, ALEXANDRA PATRICIA  
    Cardiovascular diseases (CVDs) are the leading global cause of mortality, with South America reflecting similar trends. Among congenital heart diseases (CHDs), atrioventricular (AV) block is included. AV block is a condition defined by abnormal electrical signal transmission between the atria and ventricles. Advances in Next-Generation Sequencing (NGS) have facilitated the identification of genetic variants associated with cardiac disorders, such as AV block. Notably, the transcription factor NKX2-5 plays a crucial role in heart development and function, and mutations in this gene have been linked to bradycardia and AV block. This article describes the case report of a young Ecuadorian child diagnosed with AV block and bradycardia. Furthermore, by performing NGS, a missense variant, p.(Tyr274Ser) substitution, in the NKX2-5 gene has been identified and classified as a variant of uncertain significance (VUS). Ancestral analysis has shown a genetic background of 16.5% African, 45.9% European, and 37.6% Native American. These findings suggest a potential association between the identified NKX2-5 variant and the patient's phenotype, highlighting the importance of integrating genomic and ancestral analyses to advance personalized diagnostics and therapeutics in diverse populations, such as the mestizo population. 2025 Ruiz-Pozo, Cadena-Ullauri, Paz-Cruz, Tamayo-Trujillo, Guevara-Ramirez, Onofre-Ruiz and Zambrano.