Complex disorders are characterized by presenting many genes and other environmental factors implicated in their etiology. The genetic bases of type 1 diabetes mellitus (T1D) suppose a major effect of the HLA complex which interacts with other genes and the environment. Much has been written about the possible implication of viral infections as triggers of T1D. This review explores the mechanisms by which the RNASEH1 gene could be involved in the etiology of T1D, due to a viral infection. The RNASEH1 gene is located in chromosome 2p25, which has been recently implicated in the susceptibility to T1D by the authors, through genetic analysis. POSIBLE IMPLICACION DEL GEN RNASEH1 EN LA ETIOLOGIA DE DIABETES MELLITUS TIPO 1* Astrid Jannet Rodriguez1 Javier Gutierrez1 Vital Balthazar1 Federico Uribe2 Gabriel Bedoya3 Juan Manuel Alfaro1 Nicolas Pineda-Trujillo1 * Este trabajo fue realizado gracias a la financiacion de Colciencias y la Universidad de Antioquia. Proyectos: “Evaluacion de genes conocidos y desconocidos en una region cromosomica segregando con Diabetes Mellitus tipo Codigo: 111534319156; “Evaluacion autoinmune y asociacion del gen TPO en cien trios familiares Antioquenos con Diabetes Mellitus tipo 1” Codigo: 8704-2449. 1 Grupo Mapeo Genetico. Departamento de Pediatria, Facultad de Medicina, Universidad de Antioquia. Medellin (Colombia). Autor de correspondencia: Nicolas Pineda-Trujilllo. M.Sc, Ph.D. E-mail: nicolas.pineda@medicina.udea. edu.co 2 Endocrinologia y Metabolismo, Departamento de Medicina Interna, Facultad de Medicina, Universidad de Antioquia. Medellin (Colombia). 3 Grupo Genetica Molecular –GENMOL– Corporacion de Patologias Tropicales, Instituto de Biologia, Universidad de Antioquia. Medellin (Colombia).