Slippage mutation rates in 15 autosomal short tandem repeat loci for forensic purposes in a Southeastern Brazilian population.

Well-defined estimates of mutation rates in highly polymorphic tetranucleotide STR loci are a prerequisite for human identification in genetics laboratory routines useful for civil and criminal investigations. Studying 15 autosomal STR loci of forensic interest (CSF1PO, D2S1338, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D19S433, D21S11, FGA, TH01, TPOX, and vWA), we detected 193 slippage mutations (189 one-step and four two-step mutations) in 148 875 parent-child allelic transfers from 5171 paternity cases with true biological relationship (15 096 individuals; 4754 trios and 417 duos; 9925 meiosis) from the state of São Paulo, a very representative population of Brazil. The overall mutation rate was 1.3 × 10-3 and the highest rates were observed at loci vWA (2.8 × 10-3 ), FGA and D18S51 (2.7 × 10-3 for both), while loci TH01 and TPOX did not present any mutations. The mean slippage mutation rate of paternal origin (1.8 × 10-3 ) was six times higher than that observed for maternal origin (0.3 × 10-3 ).

17 Y-STR haplotype diversity in São Paulo state (southeast of Brazil).

A sample of 158 Brazilian males from São Paulo (SP), Brazilian southeast, was typed for 17 Y-STR loci (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635, YGATA_H4.1, and DYS385ab). A total of 158 haplotypes were identified, of which all were unique. The haplotype diversity and discrimination capacity were calculated in 1.0 and the genetic diversity was 67.4%. Pairwise haplotype distances showed that the São Paulo population is not significantly different from Rio de Janeiro and Portugal, but is different from African and Native American.

Population genetic analysis of insertion-deletion polymorphisms in a Brazilian population using the Investigator DIPplex kit.

The aim of this study was to estimate the diversity of 30 insertion/deletion (INDEL) markers (Investigator(®) DIPplex kit) in a sample of 519 individuals from six Brazilian states and to evaluate their applicability in forensic genetics. All INDEL markers were found to be highly polymorphic in the Brazilian population and were in Hardy-Weinberg equilibrium. To determine their forensic suitability in the Brazilian population, the markers were evaluated for discrimination power, match probability and exclusion power. The combined discrimination power (CDP), combined match power (CMP) and combined power of exclusion (CPE) were higher than 0.999999, 3.4 × 10(-13) and 0.9973, respectively. Further comparison of 29 worldwide populations revealed significant genetic differences between continental populations and a closer relationship between the Brazilian and European populations.

Identification of the third/extra allele for forensic application in cases with TPOX tri-allelic pattern.

Genotyping of polymorphic short tandem repeats (STRs) loci is widely used in forensic DNA analysis. STR loci eventually present tri-allelic pattern as a genotyping irregularity and, in that situation, the doubt about the tri-allele locus frequency calculation can reduce the analysis strength. In the TPOX human STR locus, tri-allelic genotypes have been reported with a widely varied frequency among human populations. We investigate whether there is a single extra allele (the third allele) in the TPOX tri-allelic pattern, what it is, and where it is, aiming to understand its genomic anatomy and to propose the knowledge of this TPOX extra allele from genetic profile, thus preserving the two standard TPOX alleles in forensic analyses. We looked for TPOX tri-allelic subjects in 75,113 Brazilian families. Considering only the parental generation (mother+father) we had 150,226 unrelated subjects evaluated. From this total, we found 88 unrelated subjects with tri-allelic pattern in the TPOX locus (0.06%; 88/150,226). Seventy three of these 88 subjects (73/88; 83%) had the Clayton's original Type 2 tri-allelic pattern (three peaks of even intensity). The remaining 17% (15/88) show a new Type 2 derived category with heterozygote peak imbalance (one double dose peak plus one regular sized peak). In this paper we present detailed data from 66 trios (mother+father+child) with true biological relationships. In 39 of these families (39/66; 59%) the extra TPOX allele was transmitted either from the mother or from the father to the child. Evidences indicated the allele 10 as the extra TPOX allele, and it is on the X chromosome. The present data, which support the previous Lane hypothesis, improve the knowledge about tri-allelic pattern of TPOX CODIS' locus allowing the use of TPOX profile in forensic analyses even when with tri-allelic pattern. This evaluation is now available for different forensic applications.

Alterações citogenéticas e moleculares em leucemia mieloide aguda: revisão e descrição de casos / Molecular and cytogenetic abnormalities in acute myeloid leukemia: review and case studies

Objective: To study the frequency of mutations that may lead to a good or bad prognosis, as well as their relation with the karyotype and immunophenotype in patients with acute myeloid leukemia. Methods: Thirty samples of patients with acute myeloid leukemia were studied, in which FLT3-ITD, FLT3-TKD and NPM1 mutations were investigated. All samples were submitted to immunophenotyping and 25 to karyotyping. Results: An occurrence of 33.3% NPM1 mutation and an equal number of FLT3-ITD mutation were observed. When only the cases with normal karyotype were studied, this figures increased to 50 and 40%, respectively. Eight percent of cases with normal karyotype and genotype NPM1+/FLT3- were included in the group of acute myeloid leukemia with good prognosis. The typical phenotype of acute myeloid leukemia with normal karyotype and mutated PM1 (HLA-DR and CD34 negative) was not observed in this small series. Conclusion: Good prognosis cases were identified in this series, emphasizing the need to include new genetic markers in the diagnostic routine for the correct classification of acute myeloid leukemia, to more properly estimate prognosis and determine treatment.

Objetivo: Estudar a frequência de mutações, que podem configurar bom ou mau prognóstico, bem como sua relação com estudo de cariótipo e imunofenotípico, em portadores de leucemias mieloides agudas. Métodos: Foram estudadas 30 amostras de portadores de leucemias mieloides agudas, que foram submetidas à pesquisa das mutações FLT3-ITD, FLT3-TKD e NPM1. Todas as amostras foram submetidas a estudo munofenotípico e 25 delas foram submetidas a estudo cariotípico. Resultados: Pudemos observar frequência de 33,3% de mutação NPM1 e igual número em FLT3-ITD, frequênciaque se elevou para 50 e 40% quando se estudaram apenas os casos com cariótipo normal. Dos casos com cariótipo normal, 8% apresentaram o genótipo NPM1+/FLT3-, migrando para o grupo de leucemia mieloide aguda de bom prognóstico. Não observamos o fenótipo típico das leucemias mieloides agudas com cariótipo normal e NPM1 mutado (HLA-DR e CD34 negativos) nesta pequena casuística. Conclusão: O presente estudo foi capaz de identificar casos de bom prognóstico, enfatizando que há necessidade de se incorporarem à rotina diagnóstica novos marcadores genéticos, para a correta estratificação prognóstica e orientação terapêutica da leucemia mieloide aguda.

Molecular and cytogenetic abnormalities in acute myeloid leukemia: review and case studies.

OBJECTIVE: To study the frequency of mutations that may lead to a good or bad prognosis, as well as their relation with the karyotype and immunophenotype in patients with acute myeloid leukemia. METHODS: Thirty samples of patients with acute myeloid leukemia were studied, in which FLT3-ITD, FLT3-TKD and NPM1 mutations were investigated. All samples were submitted to immunophenotyping and 25 to karyotyping. RESULTS: An occurrence of 33.3% NPM1 mutation and an equal number of FLT3-ITD mutation were observed. When only the cases with normal karyotype were studied, this figures increased to 50 and 40%, respectively. Eight percent of cases with normal karyotype and genotype NPM1+/FLT3- were included in the group of acute myeloid leukemia with good prognosis. The typical phenotype of acute myeloid leukemia with normal karyotype and mutated NPM1 (HLA-DR and CD34 negative) was not observed in this small series. CONCLUSION: Good prognosis cases were identified in this series, emphasizing the need to include new genetic markers in the diagnostic routine for the correct classification of acute myeloid leukemia, to more properly estimate prognosis and determine treatment.