Clinical features and prognosis of B-cell acute lymphoblastic leukemia children with intrachromosomal amplification of chromosome 21 / 白血病·淋巴瘤

Objective:To investigate the clinical features and prognosis of B-cell acute lymphoblastic leukemia (B-ALL) children with intrachromosomal amplification of chromosome 21 (iAMP21).Methods:The data of 233 children diagnosed with B-ALL who received chemotherapy according to Chinese Children Cancer Group (CCCG) - acute lymphoblastic leukemia -2015 (CCCG-ALL-2015) protocol in the Affiliated Union Hospital of Fujian Medical University from January 2019 to December 2020 were retrospectively analyzed. These patients were divided into iAMP21 group and non-iAMP21 group according to whether iAMP21 was positive in the bone marrow fluid of children before chemotherapy based on ETV6-RUNX1 probe fluorescence in situ hybridization. Children in iAMP21 group received CCCG-ALL-2015 intermediate-risk group regimen induction chemotherapy, while children in non-iAMP21 group received different intensities of chemotherapy according to the clinical risk classification. The clinicopathological characteristics of patients were compared in both groups, the therapeutic efficacy and prognosis of B-ALL children with iAMP21 was analyzed.Results:iAMP21 was found in 5 (2.1%) of 233 B-ALL children. The median hemoglobin concentration in iAMP21 group was higher than that in non-iAMP21 group [99 g/L (71-148 g/L) vs. 74 g/L (30-156 g/L); U = 268.50, P = 0.043]; there were 4 cases (80%) with bone pain in iAMP21 group (5 cases) and 53 cases (23.2%) with bone pain in non-iAMP21 group (228 cases),and the difference in the osteoarticular pain incidence of both groups was statistically significant ( χ2 = 8.53, P = 0.017). There were no significant differences in the proportion of patients with different gender, age, white blood cell counts, platelet counts, hepatosplenomegaly between the two groups (all P > 0.05). Among 5 children with iAMP21, 1 patient was detected with high CRLF2 expression and 1 patient with IKZF1 1-8 exon loss of heterozygosity. The above mentioned two children with iAMP21, whose minimal residual disease (MRD) were still positive after consolidation therapy, and then they received chimeric antigen receptor T-cell treatment and hematopoietic stem cell transplantation. MRD of the other 3 children with iAMP21 turned negative after induction therapy. Up to the last follow-up in October 2021, 5 patients with iAMP21 had disease-free survival. Conclusions:The incidence of B-ALL children with iAMP21 is about 2%. These patients are prone to osteoarticular pain and have relatively mild anemia. The curative effect of some children is still poor after active treatment,which needs to be further clarified with more samples.

Desenvolvimento de um teste para a trissomia do cromossomo 21 através da análise de ácidos nucleicos fetais no plasma materno por sequenciamento de última geração / Development of a trisomy 21 test by analysis of fetal nucleic acids in maternal plasma by next generation sequencing

O objetivo do presente trabalho foi o desenvolvimento de um teste não invasivo para a trissomia do cromossomo 21 através da análise de ácidos nucleicos fetais livres no plasma materno por sequenciamento de última geração realizado no sequenciador automático Ion Torrent. A metodologia proposta para o teste é a análise de SNPs com alta taxa de heterozigosidade na população brasileira localizados em dois genes presentes no cromossomo 21 (PLAC4 e C21orf105), e a detecção da cópia extra do cromossomo 21 é feita pela razão dos alelos desses SNPs, sendo que a razão de 1:1 indica que o feto é normal, e a razão de 2:1 indica que o feto tem uma cópia extra do cromossomo 21. Para a validação da metodologia foram utilizadas 50 amostras de DNA livre extraídas de líquido amniótico, previamente caracterizadas por análise citogenética consideradas como o padrão ouro pois contém apenas material genético fetal abundante. A metodologia foi validada com sucesso nessas amostras, sendo que as 24 amostras de fetos com trissomia foram claramente distinguidas das 26 amostras de fetos normais. A metodologia validada foi aplicada a 44 amostras de DNA livre extraídas de plasma de gestantes (21 amostras de fetos com trissomia do 21 e 23 de fetos normais), porém não foi possível fazer a distinção entre fetos normais e fetos com trissomia do 21, possivelmente devido à variações na fração fetal do DNA livre em relação à fração materna. Como nosso objetivo principal não foi alcançado, Propomos aqui que o teste realizado em líquido amniótico seja utilizado como uma alternativa mais simples, rápida e barata ao cariótipo convencional atualmente utilizado para fazer o diagnóstico da trissomia do cromossomo 21 em amostras coletadas por procedimentos invasivos, enquanto as deficiências do teste não-invasivo pelo plasma materno são aprimoradas...

The purpose of this study was to develop a test for trisomy 21 by analyzing cell-free fetal nucleic acids in maternal plasma by next-generation sequencing performed on automated sequencer Ion Torrent. The proposed methodology for the test is based on analysis of SNPs with high heterozygosity rates in Brazilian population, located in two genes present on chromosome 21 (PLAC4 and C21orf105), and the detection of the extra copy of chromosome 21 is made by the allelic-ratio of these SNPs, where 1:1 ratio indicates a normal fetus, and the 2:1 ratio indicates that the fetus has an extra copy of chromosome 21. In order to validate the methodology 50 cell-free DNAs extracted from amniotic fluid were used representing a gold standard since it contains abundant genetic material exclusively from the fetus. The methodology has been successfully validated in these samples, all the 24 samples from fetuses with trisomy 21 were clearly distinguished from 26 samples of normal fetuses. The validated method was applied to 44 cell-free DNA samples extracted from plasma of pregnant women (21 samples from fetuses with trisomy 21 and 23 from normal fetuses), but unfortunately it was not possible to distinguish between normal and trisomy 21 fetuses, possibly due to variations on the fetal fraction of the cell-free DNA in relation to maternal fraction. As our main goal was not achieved, we propose here that the test performed on amniotic fluid sample could be used as a simpler, faster and cheaper alternative test to traditional karyotype, which is used nowadays to make the diagnosis of trisomy 21 in samples collected by invasive procedures. In parallel, minor improvements in the described method may enable its clinical use...

Intrachromosomal amplification of chromosome 21 (iAMP21) detected by ETV6/RUNX1 FISH screening in childhood acute lymphoblastic leukemia: a case report

Chromosome abnormalities that usually define high-risk acute lymphoblastic leukemia are the t(9;22)/ breakpoint cluster region protein-Abelson murine leukemia viral oncogene homolog 1, hypodiploid with < 44 chromosomes and 11q23/ myeloid/lymphoid leukemia gene rearrangements. The spectrum of acute lymphoblastic leukemia genetic abnormalities is nevertheless rapidly expanding. Therefore, newly described chromosomal aberrations are likely to have an impact on clinical care in the near future. Recently, the rare intrachromosomal amplification of chromosome 21 started to be considered a high-risk chromosomal abnormality. It occurs in approximately 2-5% of pediatric patients with B-cell precursor acute lymphoblastic leukemia. This abnormality is associated with a poor outcome. Hence, an accurate detection of this abnormality is expected to become very important in the choice of appropriate therapy. In this work the clinical and molecular cytogenetic evaluation by fluorescence in situ hybridization of a child with B-cell precursor acute lymphoblastic leukemia presenting the rare intrachromosomal amplification of chromosome 21 is described.

A rare non-Robertsonian translocation involving chromosomes 15 and 21 / Uma rara translocacao nao robertsoniana envolvendo os cromossomos 15 e 21

CONTEXT: Robertsonian translocations (RT) are among the most common balanced structural rearrangements in humans and comprise complete chromatin fusion of the long arm of two acrocentric chromosomes. Nevertheless, non-Robertsonian translocation involving these chromosomes is a rare event. CASE REPORT: We report a de novo unbalanced translocation involving chromosomes 15 and 21. The newborn was the daughter of a 29-year-old mother and a 42-year-old father. The couple was non-consanguineous. Clinical findings led to the diagnosis of Down syndrome (DS) with severe congenital heart defects (persistent arterial duct, and complete atrioventricular septal defect), as well as low birth length and weight (< 5th and < 10th percentile, respectively, based on specific measurement curves for DS). Conventional cytogenetic analysis revealed the karyotype 46,XX,der(15)(15pter→15q26.2::21q11.2→21qter). The translocation was confirmed by means of fluorescence in situ hybridization. The parents had normal karyotypes. CONCLUSIONS: Differently from RT, in our case a rare event occurred involving the distal segment of 15q and the proximal segment of 21q. Only two reports of this translocation, involving chromosomes 15 and 21 but different breakpoints, have been described so far. The association between 21q duplication and 15q deletion makes it difficult to separate the effect of each chromosome, but might also be responsible for increasing the growth retardation, as detected in our case. Cytogenetic analysis on DS patients is mandatory not only to confirm the diagnosis, but also to assess the risk of recurrence at genetic counseling, as well as to evaluate the contribution of other chromosome aberrations in the final phenotype. .

CONTEXTO: Translocações robertsonianas (TR) estão entre os rearranjos estruturais balanceados mais comuns em humanos e compreendem a fusão da cromatina completa do braço longo de dois cromossomos acrocêntricos. No entanto, são raras as translocações não Robertsonianas envolvendo esses cromossomos. RELATO DE CASO: Nós descrevemos uma translocação não balanceada de novo envolvendo os cromossomos 15 e 21. A recém-nascida era filha de uma mãe de 29 anos e de um pai de 42 anos, casal não consanguíneo. Os achados clínicos levaram ao diagnóstico de síndrome de Down (SD) com defeitos cardíacos congênitos graves (persistência do canal arterial e defeito do septo atrioventricular completo), além de baixos comprimento e peso ao nascimento (< 5o e < 10o percentil em curvas de medidas específicas para SD, respectivamente). A análise citogenética convencional revelou o cariótipo 46,XX,der(15)(15pter→15q26.2::21q11.2→21qter). A translocação foi confirmada por hibridação in situ fluorescente. Os pais apresentavam cariótipo normal. CONCLUSÕES: Diferentemente das TR, nesse caso ocorreu evento raro envolvendo o segmento distal de 15q e o proximal de 21q. Apenas dois relatos dessa translocação, envolvendo os cromossomos 15 e 21 e diferentes pontos de quebra, já foram descritos. A associação entre duplicação 21q e deleção 15q dificulta a distinção dos efeitos de cada cromossomo, mas poderia também ser responsável pelo acentuado retardo de crescimento. A análise citogenética é obrigatória em pacientes com SD não apenas para confirmar o diagnóstico, mas também para avaliar o risco de recorrência no aconselhamento genético, bem como avaliar a contrib...

Complicações materno-fetais da biópsia de vilo corial: experiência de um centro especializado do Nordeste do Brasil / Fetal and maternal complications of chorionic villus sampling: results from a specialized center in the Northeast of Brazil

OBJETIVO: avaliar complicações maternas e fetais após realização de biópsia de vilo corial (BVC) para diagnóstico pré-natal de alterações genéticas, na cidade de Salvador (BA). MÉTODOS: série de 958 gestantes de risco para cromossomopatias, submetidas à BVC realizada entre a nona e a 24ª semanas de gestação, por via transabdominal, utilizando agulha espinhal 18G 3½, guiada por ultra-sonografia, entre 1990 e 2006. As variáveis para a análise de complicações imediatas foram cólicas uterinas, hematoma subcoriônico, punção acidental da cavidade amniótica, dor no local da punção, amniorrexe, desconforto abdominal, bradicardia fetal e sangramento vaginal, e para complicações tardias, dor abdominal, sangramento vaginal, amniorrexe, infecção e abortamento espontâneo. Complicações obstétricas e fetais (parto prematuro, descolamento prematuro de placenta, placenta prévia e malformações anatômicas fetais) foram também estudadas. Para análise estatística, utilizaram-se o chi² e o teste t de Student ou Mann-Whitney; o nível de significância foi 5 por cento. RESULTADOS: a média de idade das gestantes foi 36,3±4,9 anos. Complicações imediatas foram encontradas em 182 (19 por cento) casos (cólica uterina em 14 por cento, hematoma subcoriônico em 1,8 por cento e punção amniótica acidental em 1,3 por cento) e tardias em 32 (3,3 por cento) casos (sangramento vaginal em 1,6 por cento, dor abdominal em 1,4 por cento, amniorrexe em 0,3 por cento e aborto espontâneo em 1,6 por cento). Não foi observado descolamento prematuro de placenta, placenta prévia ou malformação fetal. CONCLUSÕES: a BVC revelou-se procedimento simples e seguro. A BVC pode ser utilizada em gestantes que necessitam de diagnóstico pré-natal devido ao risco de anomalias genéticas.

PURPOSE: to evaluate fetal maternal complications after chorionic villus sampling (CVS) for prenatal diagnosis of genetic disorders in pregnant women of Salvador (BA), Brazil. METHODS: case-series study of 958 pregnancies with high risk for chromosomal abnormality submitted to CVS transabdominal between the ninth to the 24th week of gestation, using an ultrasound-guided 18G 3½ spinal needle, from 1990 to 2006. The variables for the analysis of immediate complications were uterine cramps, subchorionic hematoma, accidental amniotic cavity punction, pain in the punction area, amniotic fluid leakage, abdominal discomfort, fetal arrhythmias and vaginal bleeding, and of late complication, abdominal pain, vaginal bleeding, amniotic fluid leakage, infection and spontaneous miscarriage. Premature labor, obstetrical complications (abruption placenta and placenta previa) and newborn malformation were also studied. Qui-square, Student’s "t" or Mann-Whitney tests were used for the statistical analysis; the significance level was 5 percent. RESULTS: maternal mean age was 36.3±4.9 years old. Immediate complications ware found in 182 (19 percent) cases (uterine cramp in 14 percent, subchorionic hematoma in 1.8 percent and accidental amniotic cavity punction in 1.3 percent). Late complications were found in 32 (3.3 percent) cases (vaginal bleeding in 1.6 percent, abdominal pain in 1.4 percent, amniotic fluid leakage in 0.3 percent and spontaneous miscarriage in 1.6 percent cases). There was no case of abruption placentae, placenta previa or fetal malformation. CONCLUSIONS: CVS is a simple and safe procedure. CVS should be performed in high risk pregnant patients who need prenatal diagnosis of fetal chromosomal abnormalities.