Genetic abnormalities associated with the t(12;21) and their impact in the outcome of 56 patients with B-precursor acute lymphoblastic leukemia.

The ETV6/RUNX1 rearrangement is found in 20-30% of children with B-cell precursor acute lymphoblastic leukemia and is associated with a good outcome. To determine the cytogenetic and molecular abnormalities associated with the ETV6/RUNX1 rearrangement and the influence of this rearrangement in patients' evolution, we analyzed the molecular cytogenetic profiles of 56 children with this rearrangement and B-cell precursor acute lymphoblastic leukemia. Secondary changes detected with conventional cytogenetics and with fluorescence in situ hybridization were found in 71.4% of cases, the most frequent being the loss of the normal ETV6 allele, 12p aberrations, duplication of the fusion gene, and trisomy 21, as in replicating the results of previous studies. In this preliminary series, with a mean follow-up of 69.3 months, secondary abnormalities did not influence patients' outcome. It seems therefore that the prognostic value of the t(12;21) does not vary and that ETV6/RUNX1 rearrangement is an independent indicator of good prognosis.

SRY gene transferred to the long arm of the X chromosome in a Y-positive XX true hermaphrodite.

Yp-specific sequences, including the testicular determinant gene SRY, have been detected and located in a 46,XX true hermaphrodite individual, using PCR amplification and fluorescent in situ hybridization (FISH). Among different Y chromosome loci tested, it was only possible to detect Yp sequences. The Y-centromere and Yq sequences were absent. Unexpectedly, the Y fragment was translocated to the long arm of one of the X chromosomes, at the Xq28 level, and the derivative (X) chromosome of the patient lacked q-telomeric sequences. To our knowledge, this is the first Yp/Xq translocation reported. The coexistence of testicular and ovarian tissue in the patient may have arisen by differential inactivation of the Y-bearing X chromosome, in which Xq telomeric sequences are missing. The possible origin of the Yp/Xq translocation, during paternal meiosis or in somatic paternal cells, is discussed.

Follow-up of chimerism in children with hematological diseases after allogeneic hematopoietic progenitor cell transplants.

Using in situ hybridization with an X and Y chromosome probe mixture, 106 bone marrow samples from 38 patients with malignant and non-malignant hematological diseases who received sex-mismatched allogeneic hematopoietic progenitor cell transplants (PCT) in a single institution within short-term intervals (1, 3, 6, 12, 24 and >24 months) have been sequentially studied. The patients received either HLA-identical (n = 31) or non-identical (n = 7) PCT. Twenty-six children showed donor chimerism, 10 children showed mixed chimerism (MC) and two children presented autologous reconstitution. Chimerism status with different parameters has been related (age, sex, donor, disease status before PCT, conditioning regimen, GVHD prophylaxis, relapse, GVHD and survival). Our results indicate that female patients (P = 0.011) and a less intensive conditioning regimen (P = 0.039) are significantly associated with the MC status. Mixed chimerism is not, per se, significantly associated with leukemia relapse but an increase of the MC is indicative of clinical relapse.

Characterization by FISH of a t(5;13) in a patient with bilateral retinoblastoma.

We have used fluorescence in situ hybridization (FISH) with a biotinylated cosmid probe (13q14) to screen 25 unrelated cases with bilateral retinoblastoma and one case with unilateral retinoblastoma. In 25 cases no deletion or chromosome rearrangements were, found. One constitutional mutation resulting from a de novo balanced chromosome translocation (5;13) in a patient with bilateral retinoblastoma was detected.

Cytogenetic analysis using simultaneous and sequential fluorescence in situ hybridization.

A sequential fluorescence in situ hybridization (FISH) technique is described. This method allows the detection of up to eighteen chromosome pairs in consecutive hybridizations (8 steps) on the same metaphase using centromeric, whole chromosome painting, and single copy DNA probes with different fluorochromes. The technique may be used with diagnostic purposes in cases with poor cytogenetic material.

Isochromosome 14q in myeloid dysplastic disorder.

A case of refractory anemia (RA) with an isochromosome 14q is described. This finding is compared with other hematologic disorders with trisomy 14 as the sole abnormality.

Acute lymphoblastic leukemia with t(4;11) in a patient previously exposed to a carcinogen.

A case of early B t(4;11)(q21;q23) acute lymphoblastic leukemia (ALL) with low white blood cell (WBC) count, without splenomegaly, short survival time, in a patient previously exposed to benzol is presented. We discuss the relationship between the t(4;11)(q21;q23) and the exposure to a carcinogen.

New chromosomal abnormality. t(1;19;?) in a case of B-chronic lymphocytic leukemia.

Cytogenetic analysis was performed on peripheral blood cells stimulated with interleukin 6 (IL-6), lipopolysaccharide from Escherichia coli (LPS), phytohemagglutinin (PHA), pokeweed mitogen (PWM) and tetradecanoyl-phorbol-acetate (TPA), in a patient with B-chronic lymphocytic leukemia, showing a t(1;19;?) translocation as the sole abnormality. To our knowledge, this translocation has not been described before in any human neoplasia. In this case, the poor response to therapy (survival time 4 months) suggested that t(1;19;?) could be related to an aggressive course of the disease.

AML1 amplification in a child with acute lymphoblastic leukemia.

We report a case of de novo acute lymphoblastic leukemia with tandem amplification of the AML1 gene located in a chromosome marker that originated from chromosome 21 and a long event-free survival.

Isochromosome 14q in childhood acute lymphoblastic leukemia.

We report a case of childhood acute lymphoblastic leukemia (ALL) with an isochromosome 14q as the sole abnormality. A review of the literature revealed that isochromosome 14 has not been previously reported in ALL. The prognostic significance of this abnormality is compared with that of other hematologic disorders with trisomy 14.

Cytogenetic study of a patient with the Sézary syndrome.

A cytogenetic study was performed in a patient with Sézary syndrome, which is a T-helper lymphoproliferative disorder. Metaphases were obtained from a phytohemagglutinin-stimulated lymphocyte culture. Normal, hypodiploid (42 to 45 chromosomes) and hypotetraploid (84 to 88 chromosomes) cells were observed. Both abnormal cell lines showed the same abnormalities involving chromosomes 1, 2, 4, 6, 10, 11, 12, 14, 16, and 20.

Cytogenetic studies in 112 cases of untreated myelodysplastic syndromes.

Cytogenetic studies were performed in 112 untreated cases of myelodysplastic syndrome (MDS) between 1985 and 1990. Among 112 patients who were examined at the time of diagnosis, 54 had an abnormal karyotype (48%). The highest frequency of chromosome abnormalities was observed in refractory anemia with excess of blasts (RAEB) and RAEB in transformation (RAEB-t) and the lowest in refractory anemia with ring sideroblasts (RARS) and chronic myelomonocytic leukemia (CMMoL). Numerical changes were observed in 19 cases and structural in 17; chromosome 8 was most frequently gained (11 cases), whereas chromosome 7 was most frequently lost (6 cases), 5q- in 14 (4 as a sole anomaly); involvement of 7q22 was seen in 3 cases, 11p in 2 patients, 11q in 3 (one patient as a sole anomaly), 12p in 4 (2 patients as a sole anomaly), i(17q) in 4 (3 patients as a sole anomaly), and complex chromosomal defects in 10 patients. If one takes into account the prognosis value, a complex karyotype and the presence of ring chromosomes were correlated with the worst prognosis, followed by -7/7q-; an intermediate prognosis corresponds to i(17q), 12p as a sole anomaly, +8 (as a sole anomaly or plus other anomalies), and involvement of 12p. Patients with a 5q- as a sole anomaly or with a normal karyotype, had the best prognosis.

Cytogenetic studies in acute nonlymphocytic leukemia.

Cytogenetic studies were performed in 74 untreated patients with acute nonlymphocytic leukemia (ANLL) between 1985 and 1988. Among 56 patients who were examined successfully at the time of diagnosis, 36 had abnormal karyotypes (64.2%). The distribution of chromosome abnormalities was uneven, according to the categories of the French-American-British (FAB) nomenclature. The highest frequency of chromosome abnormalities was observed in ANLL M4 with bone marrow (BM) eosinophilia (M4Eo). Numerical changes were observed in 11 cases; chromosome 8 was most frequently gained (11 patients), whereas chromosome 7 was most frequently lost (4 patients). Structural rearrangements were detected in 18 patients. Involvement of 16q22 was noted in 7 patients, 5q- was noted in 5, t(8;21) in 3, t(1;7) in 2, del(20) in 2, and involvement of 11q23 was noted in 2. The inversion of chromosome 16 was restricted to the M4Eo subtype. This study identified a novel abnormality [inv(2) (p11.2q11.2)] that had not been reported previously by other investigators.

ETV6/RUNX1 rearrangement in childhood B-precursor acute lymphoblastic leukemia with normal karyotypes or without cytogenetic results.

The ETV6/RUNX1 rearrangement (also known as TEL/AML1) was evaluated in 39 children with B-precursor acute lymphoblastic leukemia (ALL) who had a normal karyotype or lack of mitoses. Forty-one point six percent of patients with normal karyotypes and 66.6% of patients without mitoses presented with the ETV6/RUNX1 rearrangement. In addition to this rearrangement, eight patients showed loss of the normal ETV6 allele; of three patients without mitoses, two showed an extra signal of the RUNX1 gene and the third showed the fusion gene duplicated and loss of the normal ETV6 allele. One patient without the ETV6/RUNX1 rearrangement and without mitoses showed two extra signals of the RUNX1 gene.

Appraisal of fluorescence in situ hybridization (FISH) techniques in prenatal diagnosis.

The reliability of FISH was appraised using probes for the X and Y chromosome and for chromosomes 12 and 18 in prenatal and adult interphase nuclei. Detection of a single hybridization spot proved to be quite reliable (80-92% positive nuclei). Detection of two hybridization spots was more difficult; percentages of nuclei showing two signals varied between 62-72%. The percentages of nuclei with the correct number of spots was higher in the metaphases occasionally found. Thus, FISH may complement but not replace cytogenetic analysis. For sex determination and for the detection of mosaicism, we suggest the use of two different probes in separate regions of the same preparation.

[Septic arthritis in children]. / La artritis séptica en el niño.

A review was made of 15 cases of septic arthritis in children. 13 of these cases corresponded to purulent arthritis, one to tuberculous arthritis and one to brucellar arthritis. All of them received diagnostic punction. Five joints received arthrotomy, by a washed-aspiration system. The antibiotic treatment was given approximately during for six weeks. We had two complications, die to a delayed diagnosis: one coxa valga and one capital femoral necrosis. It is important the insist on a early diagnosis and decompressive arthrotomy, specially in those cases in which the hip is the joint affected.

Histone electrophoretic pattern in the characterization of synaptonemal complexes.

The presence of a stoechiometric electrophoresis pattern of histones in carefully isolated synaptonemal complexes is reported. The use of this pattern is suggested as an internal standard of synaptonemal complex purification, in addition to the more generally used electron micrographs. This is especially useful in experiments leading to the characterization of the protein components of SCs. The use of mice of an age at which pachytenes predominate (90%) in the prophase-cell population is also advantageous to improve the final yield in synaptonemal complexes.