In South America, a high proportion of the population is of Hispanic origin with an important representation in Colombia. Since nothing is known about the contribution of BRCA1 and BRCA2 germline mutations to hereditary breast/ovarian cancer in the Hispanic population from Colombia, we conducted the first study of 53 breast/ovarian cancer families from this country. Comprehensive BRCA mutation screening was performed using a range of techniques, including DHPLC, SSCP, and PTT, followed by DNA sequencing analysis. Thirteen deleterious germline mutations (24.5%) were identified in 53 families, comprising eight in BRCA1 and five in BRCA2. The two recurrent BRCA1 mutations, 3450 delCAAG and A1708E, accounted for 100% of all BRCA1 mutations identified in this cohort and the recurrent 3034 delACAA BRCA2 mutation for 40% of all BRCA2 mutations. Haplotype analyses suggested that each of these mutations has arisen from a common ancestor. The prevalence of BRCA1 or BRCA2 mutations was 50% in multiple case breast cancer families, and was 33% for the breast-ovarian cancer families. Our findings show that BRCA mutations account for a substantial proportion of hereditary breast/ovarian cancer in Colombia. The spectrum of mutations differed completely to that previously reported in Hispanic families of predominantly Mexican origin from Southern California [1] suggesting that specific genetic risk assessment strategies for the different Hispanic populations in South America and in the United States need to be developed.
Serological HLA types (A, B, C, DR and DQ loci) were studied in five different Indian tribes (Cubeo, Tucano, Coreguaje, Embera and Noanama) belonging to two distinct linguistic families. For all the MHC loci, the range of variation among the five tribes was enormous. Two tribes, Cubeo and Tucano, showed a wide spectrum of antigenic specificities which seemed to be due to admixture from non-tribal groups, while in the other three tribes the polymorphisms of various HLA loci showed restricted distributions. The gene frequency data, when converted to a kinship matrix and a two-dimensional eigenvector plot, indicated that members of the same linguistic family tend to have greater genetic affinity.
The records of 15 years of paediatric necropsies in the Department of Pathology of the Hospital San Ignacio in Bogota were reviewed and the results classified according to the various types of genetic pathology. It is shown that out of 1463 paediatric necropsies, 377 (25-8%) had either a congenital defect or a disease considered as genetic to some extent. Simple Mendelian diseases and chromosomal disorders account together for more than 5% of the total deaths. When the pathologies with a complex genetic contribution to the aetiology are also taken into account, the figure rises to more than 20%. Overall, the study shows that the burden of genetic pathology is also important in countries, like Colombia, where other causes of death have traditionally been the main concern of public health measures.
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