Novel mutations associated with pyruvate kinase deficiency in Brazil.

Background: Pyruvate kinase deficiency is a hereditary disease that affects the glycolytic pathway of the red blood cell, causing nonspherocytic hemolytic anemia. The disease is transmitted as an autosomal recessive trait and shows a marked variability in clinical expression. This study reports on the molecular characterization of ten Brazilian pyruvate kinase-deficient patients and the genotype-phenotype correlations.

Clinical and molecular epidemiology of neonatal leukemia in Brazil.

The clinical and molecular findings of 77 cases of neonatal leukemia (NL) and 380 of infant leukemia (IL) were selected to distinguish features between NL and IL. Somatic gene mutations associated with acute leukemia including FLT3, RAS and PTPN11 were revisited. There were 42 cases of congenital leukemia associated with Down syndrome (DS) and 39 of these cases presented features of acute myeloid leukemia (AML)-M7.

NQO1 rs1800566 (C609T), PON1 rs662 (Q192R), and PON1 rs854560 (L55M) polymorphisms segregate the risk of childhood acute leukemias according to age range distribution.

Purpose: The risk of developing childhood leukemia has been associated with gene polymorphisms that decrease the activity of detoxifying metabolic enzymes and enzymes involved in systemic oxidative stress. We investigated the NQO1 and PON1 polymorphisms for associations with susceptibility to childhood leukemia.

Methods: Samples from 1,027 Brazilian children (519 acute lymphoblastic leukemia, ALL; 107 acute myeloid leukemia, AML; 401 controls) were analyzed.

Auditory-evoked response analysis in Brazilian patients with sickle cell disease.

The objective of the present study was to evaluate the integrity of the peripheral and central auditory systems of sickle cell disease (SCD) patients, through electrophysiological evaluation utilizing auditory evoked potentials, and comparing the results obtained in SCD patients with individuals without SCD. A total of 80 individuals were evaluated: 40 SCD patients; and 40 healthy age- and sex-matched controls. Brainstem auditory evoked response (BAER) was used to check neural integrity and electrophysiological thresholds, and cognitive potential (P300) to analyse the auditory selective attention.

ETV6-RUNX1 fusion gene and additional genetic changes in infant leukemia: a genome-wide analysis.

Acute lymphoblastic leukemia (ALL) in infants is characterized by a high frequency of MLL gene rearrangements. By contrast, the t(12;21) ETV6-RUNX1 fusion gene is typically detected in children older than 2 years. In a series of Brazilian infant leukemia cases, however, four younger cases harbored ETV6-RUNX1, at ages 2, 3, 5, and 7 months.

Detection of mutations in GATA1 gene using automated denaturing high-performance liquid chromatography and direct sequencing in children with Down syndrome.

Denaturing high-performance liquid chromatography (dHPLC) was developed to screen DNA variations by separating heteroduplex and homoduplex DNA fragments by ion-pair reverse-phase liquid chromatography. In this study, we have evaluated the dHPLC screening method and direct sequencing for the detection of GATA1 mutations in peripheral blood and bone marrow aspirates samples from children with Down syndrome (DS). Cases were ascertained consecutively as part of an epidemiological study of DS and hematological disorders in Brazil.

MTHFR 677C-->T and 1298A-->C polymorphisms in children with Down syndrome and acute myeloid leukemia in Brazil.

Down syndrome (DS) is an important risk factor associated with acute leukemia (AL). The presence of polymorphisms that reduce 5,10-methylenetetrahydrofolate reductase (MTHFR) activity has been linked to the multifactorial leukemogenic process. The authors have conducted a study to test whether 677C-->T and/or 1298A-->C polymorphisms of MTHFR would play an additional role in susceptibility of acute myeloid leukemia (AML) in DS children.

GATA1 mutations in acute leukemia in children with Down syndrome.

It has been reported that somatic mutations in the X-linked GATA1 gene are present in hematological clonal disorders in children with Down syndrome (DS). We analyzed retrospective samples of DS children with acute myeloid leukemia, transient leukemia (TL), and myelodysplastic syndrome (MDS) to test whether the specificity of GATA1 mutations can be helpful in distinguishing these hematopoietic disorders. A total of 49 samples were subjected to GATA1 mutation screening by direct sequencing and denaturing polyacrylamide gel electrophoresis (PAGE).

Transient neonatal myeloproliferative disorder without Down syndrome and detection of GATA1 mutation.

Transient myeloproliferative disorder is a form of self-limited leukemia that occurs almost exclusively in neonates with Down syndrome. The authors report an unusual case of a newborn without constitutional trisomy 21 who developed undifferentiated leukemia and subsequently achieved clinical and molecular remission without chemotherapy. Cytogenetics and molecular analysis have shown trisomy 21 and GATA1 mutation restricted to leukemic cells.