Pharmacogenetics of pediatric acute lymphoblastic leukemia in Uruguay: adverse events related to induction phase drugs.

In Uruguay, the pediatric acute lymphoblastic leukemia (ALL) cure rate is 82.2%, similar to those reported in developed countries. However, many patients suffer adverse effects that could be attributed, in part, to genetic variability. This study aims to identify genetic variants related to drugs administered during the induction phase and analyze their contribution to adverse effects, considering individual genetic ancestry. Ten polymorphisms in five genes (ABCB1, CYP3A5, CEP72, ASNS, and GRIA1) related to prednisone, vincristine, and L-asparaginase were genotyped in 200 patients. Ancestry was determined using 45 ancestry informative markers (AIMs). The sample ancestry was 69.2% European, 20.1% Native American, and 10.7% African, but with high heterogeneity. Mucositis, Cushing syndrome, and neurotoxicity were the only adverse effects linked with genetic variants and ancestry. Mucositis was significantly associated with ASNS (rs3832526; 3R/3R vs. 2R carriers; OR: = 6.88 [1.88-25.14], p = 0.004) and CYP3A5 (non-expressors vs. expressors; OR: 4.55 [1.01-20.15], p = 0.049) genes. Regarding Cushing syndrome, patients with the TA genotype (rs1049674, ASNS) had a higher risk of developing Cushing syndrome than those with the TT genotype (OR: 2.60 [1.23-5.51], p = 0.012). Neurotoxicity was significantly associated with ABCB1 (rs9282564; TC vs. TT; OR: 4.25 [1.47-12.29], p = 0.007). Moreover, patients with <20% Native American ancestry had a lower risk of developing neurotoxicity than those with ≥20% (OR: 0.312 [0.120-0.812], p = 0.017). This study shows the importance of knowing individual genetics to improve the efficacy and safety of acute lymphoblastic leukemia.

An updated examination of the perception of barriers for pharmacogenomics implementation and the usefulness of drug/gene pairs in Latin America and the Caribbean.

Pharmacogenomics (PGx) is considered an emergent field in developing countries. Research on PGx in the Latin American and the Caribbean (LAC) region remains scarce, with limited information in some populations. Thus, extrapolations are complicated, especially in mixed populations. In this paper, we reviewed and analyzed pharmacogenomic knowledge among the LAC scientific and clinical community and examined barriers to clinical application. We performed a search for publications and clinical trials in the field worldwide and evaluated the contribution of LAC. Next, we conducted a regional structured survey that evaluated a list of 14 potential barriers to the clinical implementation of biomarkers based on their importance. In addition, a paired list of 54 genes/drugs was analyzed to determine an association between biomarkers and response to genomic medicine. This survey was compared to a previous survey performed in 2014 to assess progress in the region. The search results indicated that Latin American and Caribbean countries have contributed 3.44% of the total publications and 2.45% of the PGx-related clinical trials worldwide thus far. A total of 106 professionals from 17 countries answered the survey. Six major groups of barriers were identified. Despite the region's continuous efforts in the last decade, the primary barrier to PGx implementation in LAC remains the same, the "need for guidelines, processes, and protocols for the clinical application of pharmacogenetics/pharmacogenomics". Cost-effectiveness issues are considered critical factors in the region. Items related to the reluctance of clinicians are currently less relevant. Based on the survey results, the highest ranked (96%-99%) gene/drug pairs perceived as important were CYP2D6/tamoxifen, CYP3A5/tacrolimus, CYP2D6/opioids, DPYD/fluoropyrimidines, TMPT/thiopurines, CYP2D6/tricyclic antidepressants, CYP2C19/tricyclic antidepressants, NUDT15/thiopurines, CYP2B6/efavirenz, and CYP2C19/clopidogrel. In conclusion, although the global contribution of LAC countries remains low in the PGx field, a relevant improvement has been observed in the region. The perception of the usefulness of PGx tests in biomedical community has drastically changed, raising awareness among physicians, which suggests a promising future in the clinical applications of PGx in LAC.

Ancestry and TPMT-VNTR Polymorphism: Relationship with Hematological Toxicity in Uruguayan Patients with Acute Lymphoblastic Leukemia.

6-Mercaptopurine (6-MP) is a thiopurine drug widely used in childhood acute lymphoblastic leukemia (ALL) therapy. Genes such as TPMT and NUDT15 have an outstanding role in 6-MP metabolism. Mutations in both genes explain a significant portion of hematological toxicities suffered by ALL Uruguayan pediatric patients. A variable number tandem repeat in the TPMT promoter (TPMT-VNTR) has been associated with TPMT expression. This VNTR has a conservative architecture (AnBmC). To explore new causes of hematological toxicities related to ALL therapy, we genotyped the TPMT-VNTR of 130 Uruguayan pediatric patients. Additionally, individual genetic ancestry was estimated by 45 ancestry-informative markers (AIMs). Hematological toxicity was measured as the number of leukopenia events and 6-MP dose along the maintenance phase. As previously reported, we found TPMT*2 and TPMT*3C alleles were associated to TPMT-VNTR A2BC and AB2C, respectively. However, contrasting with other reports, TPMT*3A allele was found in a heterogeneous genetic background in linkage equilibrium. Patients carrying more than 5 A repeats present a significant higher number of leukopenia events among patients without TPMT and/or NUDT15 variants. Native American ancestry and the number of A repeats were significantly correlated with the number of leukopenia events. However, the correlation between Native American ancestry and the number of leukopenia events was lost when the number of A repeats was considered as covariate. This suggests that TPMT-VNTR alleles are more relevant than Native American ancestry in the hematological toxicity. Our results emphasize that TPMT-VNTR may be used as a pharmacogenetic biomarker to predict 6-MP-related hematological toxicity in ALL childhood therapy.

Prevalencia de anemia en niñas/os de 6 a 48 meses que concurren a dos CAIF de la ciudad de Salto / Prevalência de anemia em crianças de 6 a 48 meses que concorrem a centros de atenção a primeira infância da cidade de salto / Prevalence of anemia in 6 to 48 month children attending to an infancy primary care center of salto city

Introducción. La anemia en los niños es un problema de salud pública importante en nuestro país, siendo la anemia por deficiencia de hierro la más frecuente. La frecuencia de anemia en el interior del país es mayor a lo observado en Montevideo. Sin embargo, no existen datos específicos del Departamento de Salto. Objetivos. Determinar la prevalencia de anemia en niños y niñas de 6 a 48 meses que concurren a dos Centros de Atención a la Primera Infancia (CAIF) de la ciudad de Salto y analizar los factores de riesgo asociados. Metodología. Se determino los niveles de hemoglobina por punción digital en 240 niños de dos CAIF, se relevaron los antecedentes perinatales del carnet del niño/a y datos de ancestralidad por medio de una encuesta a los responsables de los niños. Resultados. La prevalencia de anemia fue de 22,5% en toda la muestra, siendo levemente mayor en el CAIF2 (27,4%) que en el CAIF1(18,4%). La frecuencia de anemia fue significativamente menor en los niños que tuvieron lactancia materna exclusiva hasta los 6 meses de edad, mientras que las restantes variables analizadas no presentaron asociación con la anemia. Conclusiones. La disminución observada de la frecuencia de anemia comparada con lo reportado en 2011 sugiere que las políticas de fortificación con hierro de los alimentos y de administración de hierro profiláctico a niños entre 6 y 24 meses ha sido positiva. Adicionalmente, la menor frecuencia de anemia observada en el CAIF1 indica la importancia de la acción coordinada entre los servicios de salud y la sociedad.

Introduction. Anemia in children is a public health problem in Uruguay, being iron deficiency anemia the most frequent etiology. The anemia prevalence is higher in regions or cities different to Montevideo. However, there is no specific data from the Salto city. Objectives. Determine and compare the prevalence of anemia in children aged 6 to 48 months from two educational institutions (CAIFs) in the city of Salto and analyze the associated risk factors. Methodology. The hemoglobin levels were determined by digital puncture in 240 children of two CAIFs, the perinatal data were obtained from the child>s card and a survey to family was used to obtain ancestry data. Results The prevalence of anemia was 22.5% in the entire sample, being slightly higher in CAIF2 (27.4%) than in CAIF1 (18.4%). The frequency of anemia is significantly lower in children who had exclusive breastfeeding until 6 months of age, while the other variables analyzed were not associated with anemia. Conclusions. The prevalence of anemia observed is lower than 2011 suggesting that the policies of iron fortification of food and administration of prophylactic iron to children between 6 and 24 months has been positive. Additionally, the lower anemia frequency observed in CAIF1 than observed in CAIF2 indicates the importance.

Introdução. A anemia é um problema de saúde pública importante em nosso pais, sendo a anemia por deficiência de ferro a mais frequente. A frequência de anemia no interior do pais é maior ao observado em Montevideo. Porém, não existem dados específicos do Departamento de Salto. Objetivos. Determinar a prevalência de anemia em crianças de 6 a 48 meses que concorrem a dois Centros de Atenção da Primeira Infância (CAIF) da cidade do Salto e analisar os fatores de risco associado. Metodologia. Determinaramse os níveis de hemoglobina por punção digital em 240 crianças dos CAIF, relevaramse os antecedentes perinatais das carteiras das crianças e os dados de ancestralidade por médio de um questionário aos responsáveis das crianças. Resultados. Na amostra completa, a prevalência de anemia foi de 22,5%, com uma porcentagem levemente maior no CAIF2 (24,4%) em comparação com o CAIF1 (18,4%). A frequência de anemia foi significativamente menor nas crianças que tiveram lactância materna exclusiva até os 6 meses de idade, entanto que o resto das variáveis analisadas não apresentaram associações com à anemia. Conclusão. A diminuição observada da frequência de anemia quando comparada com o reportado em 2011 sugere que as políticas de fortificação com ferro dos alimentos e de administração profilática com ferro em crianças entre 6 e 24 meses tem sido positiva. Adicionalmente, a menor frequência de anemia observada no CAIF1 indica a importância da ação coordenada entre os serviços de saúde e sociedade.

The -(α)(5.2) Deletion Detected in a Uruguayan Family: First Case Report in the Americas.

In Uruguay, α-thalassemia (α-thal) mutations were introduced predominantly by Mediterranean European immigrant populations and by slave trade of African populations. A patient with anemia with hypochromia and microcytosis, refractory to iron treatment and with normal hemoglobin (Hb) electrophoresis was analyzed for α-thal mutations by multiplex gap-polymerase chain reaction (gap-PCR), automated sequencing and multiplex ligation-dependent probe amplification (MLPA) analyses. Agarose gel electrophoresis of the multiplex gap-PCR showed a band of unexpected size (approximately 700 bp) in the samples from the proband and mother. Automated sequencing of the amplified fragment showed the presence of the -(α)(5.2) deletion (NG_000006.1: g.32867_38062del5196) [an α-thal-1 deletion of 5196 nucleotides (nts)]. The MLPA analysis of the proband's sample also showed the presence of the -(α)(5.2) deletion in heterozygous state. We report here the presence of the -(α)(5.2) deletion, for the first time in the Americas, in a Uruguayan family with Italian ancestry, detected with a previously described multiplex gap-PCR.

Beta-globin gene cluster haplotypes in Afro-Uruguayans from two geographical regions (South and North).

The beta-globin gene cluster haplotypes were identified in 52 and 40 chromosomes from two Afro-Uruguayan populations located in the South and North of the country, respectively. In both regions, the 5' haplotype 2 (+ - - - -), characteristic of non-African populations, was the most frequent, reflecting a strong process of admixture in Afro-Uruguayans (0.355 and 0.262, respectively). The haplotypes 3 (- - - - +) and 4 (- + - - +), characteristics of African sub-Saharan populations, present inverse frequencies in North and South: whereas in the South haplotype 3 is the second most frequent (0.232), and haplotype 4 presents a low frequency (0.019), in the North haplotype 4 is the third most frequent (0.140), and haplotype 3 only reaches an intermediate frequency (0.088). The pairwise F(ST) and the exact test of differentiation show genetic heterogeneity between both regions. Nei's genetic distance show that South and North present affinities with Bantu groups, although the North present the smallest genetic distance with the Mandenka, a Senegalese population. With respect to 3' haplotypes, haplotype I was the most frequent in both populations, followed by haplotype II, characteristic of sub-Saharan Africans. The high frequencies of haplotype III-Asian could indicate admixture with Native American populations. The differences observed between both Uruguayan regions could be explained by microevolutionary events as genetic drift, founder effects, differential admixture, and/or distinct origin of the African slaves introduced in those regions.

Asociación de hemoglobina S (HbS) y beta talasemia en dos pacientes del Centro Hemato-Oncológico del Hospital Pereira Rossell / Association between S haemoglobin and S-thalassemia in two patients of the Haematologic and Oncologic Centre of the Pereira Rossell Children Hospital

Associación del alelo b S que produce hemoglobina S (HbS) y de un alelo de beta talasemia (btal), ocurre principalmente en poblaciones que tienen simultáneamente ascendencia africana y mediterránea, y provoca un síndrome drepanocítico denominado HbS-beta talasemia. Este síndrome presenta una gran heterogeneidad clínica y genética debida en gran parte al alelo talasémico presente. Los individuos que portan un alelo talasémico b 0 presentan, en general, un curso clínico similar a los homocigotas para el alelo b S de la HbS. En cambio, los que portan un alelo b + presentan un curso clínico variable, dependiendo de la reducción en la síntesis de cadena de beta globina. En este estudio se describe el caso clínico de dos pacientes con HbS-beta talasemia que consultaron en el Centro Hemato-Oncológico Pediátrico del Hospital Pereira Rossell. Se analizó el genotipo de los dos pacientes por medio de secuenciación automática del gen de la beta globina. Se demostró la presencia del alelo talasémico b + IVS-1-110- A en uno de los pacientes y del alelo b 0 codón39 C-T en el otro paciente, por lo cual ambos son heterocigotos compuestos b S/b tal. Se discute la relación entre los datos clínicos y paraclínicos con los resultados del diagnóstico molecular. También se discute la importancia del diagnóstico molecular en relación con la composición y estructura de la población uruguaya.