title: [Insulin-dependent diabetes mellitus in Santiago, Chile: the role of immunogenetic and environmental factors].
abstract: The role of HLA class II alleles in the genetic susceptibility to develop insulin-dependent diabetes mellitus (IDDM) was examined by means of PCR and oligospecific probes in 63 IDDM children and 74 controls subjects. In diabetic patients we found a significant increase in the alleles frequency DR3, DR4, DQB1*0302 and DQA1*0301 compared to the control group, where the most prevalent alleles were DR2, DR14 (DRB1*1402), DQA1*0101 and DQA1*0201. All the risk genotypes in the diabetic group were similar than in other caucasian groups: DR3/DR4-DQB1*0201/0302-DQA1*0301/0501 and DR4/DR4-DQB1*0302/0302-DQA1*0301/0301. The homozygote character no asp57 conferred an absolute risk (AR) of 3.87 and the marker Arg52 an AR of 5.78/100.000 bab year. The homozygosis for both markers (no Asp57 + Arg52) had an AR of 7.56/100.000 bab year. Regarding environmental factors associated with IDDM, our population under study showed a low prevalence of infectious agents (mainly mumps and rubella, specifically associated with IDDM) and a high prevalence of effective breast-feeding (over 3 months). These factors could be exercising a protector role in the development of IDDM. The factors that appear to be important in the low incidence of IDDM in Santiago de Chile are: the low prevalence of infectious agents related to IDDM, the high percentage of breast-feeding children in the population, the reduced frequency of susceptible molecules as DR3, DQB1*0201 (compared to other caucasian groups) and the presence of protective genotypes related to DR13 and DR14 observed in the non diabetic children.
authors.affiliation: Grupo de Biología Moleculary, Universidad de Chile, Santiago, Chile.
authors.forename: F
authors.initials: F
authors.lastname: Pérez
authors.forename: M
authors.initials: M
authors.lastname: Calvillán
authors.forename: J L
authors.initials: JL
authors.lastname: Santos
authors.forename: E
authors.initials: E
authors.lastname: Carrasco
mesh_terms: D000293:Adolescent; D000483:Alleles; D001942:Breast Feeding; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics*; D004783:Environmental Microbiology; D005260:Female; D005819:Genetic Markers; D005838:Genotype; D006684:HLA-DR Antigens; D006801:Humans; D007223:Infant; D007227:Infant Nutritional Physiological Phenomena; D008297:Male; D015596:Nutrition Assessment
chemical_list: D005819:Genetic Markers; D006684:HLA-DR Antigens
vernacular_title: Diabetes mellitus insulino-dependiente en Santiago de Chile: rol patogenético de factores inmunogenéticos y ambientales.