47 M arcadores genéticos (H LA) y perfil de auto-anticuerpos en una familia mapuche con un caso de diabetes tipo 1 Sylvia Asenjo M 1 , Andrea Gleisner E 1 , Francisco Pérez B 2a . HLA genetic markers and auto-antibody profile in a Mapuche family with a case affected of type 1 diabetes Background : Type 1 diabetes (DM1) is caused by an autoimmune pro- cess that destroys beta cells of pancreas. Not all carriers of susceptible HLA genes and positive for au- toantibodies develop the disease. Environmental factors play a role in triggering the autoimmune pro- cess. Aim: To analyze an exceptional case of DM1 in a Mapuche family in the context of genetic, im- munological and environmental factors. Subjects and methods : A study of a family with an affected female child was carried out in a Mapuche community in Southern Chile (VIII region). This is an unique and sporadic DM1 case with Mapuche heritage. Nutritional and viral infections data were col- lected by interview and clinical records. A genetic analysis by PCR was done to detect class I and II HLA genes by reverse dot blot. Results: The proband, her mother and sister had positive islet cell anti- bodies (ICA). Her father and brother were negative. All the family was positive for anti glutamic decar- boxylase antibodies (GAD65). All subjects had HLA-DRB1 0407/0407 and HLA-DQB1 0302/0302 alle- les. The index case and her father were homozygotes for the HLA-A1:A*68012/A*68012 allele. Mean breast feeding lapse was 18 months in all children. No evidences for viral infections such as rubella, mumps or measles were found in this family. Conclusions : There was an altered profile of autoanti- bodies in the family of the index case. All genotypes were comparable with the European population where the diabetogenic combination DR4/DQB1*0302 is the most prevalent. No environmental factors could be incriminated as triggers of the disease (Rev Méd Chile 2004; 132: 47-50). ( Key Words: Diabetes Mellitus, insulin dependent, Ethnic groups; HLA-DR antigens). Recibido el 29 de mayo, 2003. Aceptado en versión corregida el 4 de septiembre, 2003. Estudio financiado parcialmente por los Proyectos FONDECYT #1000944 y MECESUP, Universidad de Chile PR005. 1 Unidad de Endocrinología Pediátrica, Facultad de Medicina, Universidad de Concepción. 2 Progra- ma de Epidemiología Genética, Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile. a Doctor en Ciencias. Correspondencia a: Dra. Sylvia Asenjo M. Unidad de Endo- crinología Pediátrica, Facultad de Medicina, Universidad de Concepción, Concepción, Chile. E mail: sasenjo@udec.cl Rev Méd Chile 2004; 132: 47-50 L a diabetes tipo 1 (DM1) constituye una de las enfermedades crónicas más comunes de la población infantil 1,2 . El registro epidemiológico de DM1 en Santiago, reveló una incidencia del orden de 2,49/100.000 hab/año para el período 1986- 1993 3 , con posterioridad, durante los años 1997- 1998 se ha observado una cifra de 4,1/100.000 hab/año 4 . Estos datos confirman, que al igual que en el resto del mundo, la diabetes tipo 1 también ha aumentado en nuestro país, de modo que Chile A RTÍCULO DE I NVESTIGACIÓN