Irén Haltrich

An international study of intrachromosomal amplification of chromosome 21 (iAMP21): cytogenetic characterization and outcome

Intrachromosomal amplification of chromosome 21 (iAMP21) defines a distinct cytogenetic subgroup of childhood B-cell precursor acute lymphoblastic leukaemia (BCP-ALL). To date, fluorescence in situ hybridisation (FISH), with probes specific for the RUNX1 gene, provides the only reliable detection method (five or more RUNX1 signals per cell). Patients with iAMP21 are older (median age 9 years) with a low white cell count. Previously, we demonstrated a high relapse risk when these patients were treated as standard risk. Recent studies have shown improved outcome on intensive therapy. In view of these treatment implications, accurate identification is essential. Here we have studied the cytogenetics and outcome of 530 iAMP21 patients that highlighted the association of specific secondary chromosomal and genetic changes with iAMP21 to assist in diagnosis, including the gain of chromosome X, loss or deletion of chromosome 7, ETV6 and RB1 deletions. These iAMP21 patients when treated as high risk showed the same improved outcome as those in trial-based studies regardless of the backbone chemotherapy regimen given. This study reinforces the importance of intensified treatment to reduce the risk of relapse in iAMP21 patients. This now well-defined patient subgroup should be recognised by World Health Organisation (WHO) as a distinct entity of BCP-ALL.

Parallel Evolution under Chemotherapy Pressure in 29 Breast Cancer Cell Lines Results in Dissimilar Mechanisms of Resistance

Background Developing chemotherapy resistant cell lines can help to identify markers of resistance. Instead of using a panel of highly heterogeneous cell lines, we assumed that truly robust and convergent pattern of resistance can be identified in multiple parallel engineered derivatives of only a few parental cell lines. Methods Parallel cell populations were initiated for two breast cancer cell lines (MDA-MB-231 and MCF-7) and these were treated independently for 18 months with doxorubicin or paclitaxel. IC50 values against 4 chemotherapy agents were determined to measure cross-resistance. Chromosomal instability and karyotypic changes were determined by cytogenetics. TaqMan RT-PCR measurements were performed for resistance-candidate genes. Pgp activity was measured by FACS. Results All together 16 doxorubicin- and 13 paclitaxel-treated cell lines were developed showing 2–46 fold and 3–28 fold increase in resistance, respectively. The RT-PCR and FACS analyses confirmed changes in tubulin isofom composition, TOP2A and MVP expression and activity of transport pumps (ABCB1, ABCG2). Cytogenetics showed less chromosomes but more structural aberrations in the resistant cells. Conclusion We surpassed previous studies by parallel developing a massive number of cell lines to investigate chemoresistance. While the heterogeneity caused evolution of multiple resistant clones with different resistance characteristics, the activation of only a few mechanisms were sufficient in one cell line to achieve resistance.

Donor-cell myelodysplastic syndrome developing 13 years after marrow grafting for aplastic anemia

Donor-cell-derived hematopoietic malignancy is a rare event after bone marrow transplantation. Most cases in the literature occurred within the first year. We present a rare case of a female patient who had a bone marrow transplant for severe aplastic anemia (SAA) at the age of two and a half years from her human leukocyte antigen-identical brother. She developed a myelodysplastic syndrome (refractory cytopenia with multilineage dysplasia) 12 years later. Initially, the malignant clone was of recipient origin, but within several months, progression to a clinically more aggressive refractory anemia with excess blasts (RAEB) was accompanied by the outgrowth of a new clone of donor origin. In this report we provide evidence proving that the patients final malignant clone arose in donor cells: cytogenetic analysis of the marrow showed a male karyotype and a t(3;21)(q26;q21) in all 62 metaphases analyzed. Interphase fluorescence in situ hybridization showed that all identifiable cells contained the Y chromosome. We conclude that donor-cell-derived hematopoietic malignancy after bone marrow transplantation can occur even after many years. We believe that the 13 years that elapsed between the transplant and the development of RAEB in our case represent the longest latency period in the literature.

Normal karyotype is a poor prognostic factor in myeloid leukemia of Down syndrome: A retrospective, international study

Myeloid leukemia of Down syndrome has a better prognosis than sporadic pediatric acute myeloid leukemia. Most cases of myeloid leukemia of Down syndrome are characterized by additional cytogenetic changes besides the constitutional trisomy 21, but their potential prognostic impact is not known. We, therefore, conducted an international retrospective study of clinical characteristics, cytogenetics, treatment, and outcome of 451 children with myeloid leukemia of Down syndrome. All karyotypes were centrally reviewed before assigning patients to subgroups. The overall 7-year event-free survival for the entire cohort was 78% (±2%), with the overall survival rate being 79% (±2%), the cumulative incidence of relapse 12% (±2%), and the cumulative incidence of toxic death 7% (±1%). Outcome estimates showed large differences across the different cytogenetic subgroups. Based on the cumulative incidence of relapse, we could risk-stratify patients into two groups: cases with a normal karyotype (n=103) with a higher cumulative incidence of relapse (21%±4%) than cases with an aberrant karyotype (n=255) with a cumulative incidence of relapse of 9% (±2%) (P=0.004). Multivariate analyses revealed that white blood cell count ≥20×109/L and age >3 years were independent predictors for poor event-free survival, while normal karyotype independently predicted inferior overall survival, event-free survival, and relapse-free survival. In conclusion, this study showed large differences in outcome within patients with myeloid leukemia of Down syndrome and identified novel prognostic groups that predicted clinical outcome and hence may be used for stratification in future treatment protocols.

Gonadoblastoma: Case report of two young patients with isochromosome 12p found in the dysgerminoma overgrowth component in one case

Gonadoblastomas are unusual neoplasias that frequently appear in the dysgenetic gonads of women with chromosome Y anomaly. We present two cases of gonadoblastoma associated with complete gonadal dysgenesis and Turner syndrome, respectively, with dysgerminoma overgrowth found in one case. We were interested in the DNA ploidy, the presence of Y chromosome DNA sequence and the status of chromosome 12p arm among the tumor cells. We performed cytophotometry to analyze the DNA content and fluorescence in situ hybridization (FISH) to identify the Y chromosome and the isochromosome 12p within the tumor cells. The cytophotometric result showed diploid DNA content in gonadoblastoma, whereas dysgerminoma revealed aneuploid DNA. The FISH result revealed Y chromosome DNA sequence within gonadoblastoma and dysgerminoma. Isochromosome 12p was identified in dysgerminoma, but not in gonadoblastoma. We conclude that gonadoblastoma and dysgerminoma have a strong association with the Y chromosome, and dysgerminoma overgrowth is due to further chromosomal aberrations, such as isochromosome 12p. Histological, immunohistocheimcal and molecular studies should render the correct diagnosis. Identifying dysgerminoma overgrowth is crucial since it is associated with adverse prognosis and requires additional therapy.

A Transgenic Mouse Model for Detection of Tissue-Specific Thyroid Hormone Action

Thyroid hormone (TH) is present in the systemic circulation and thus should affect all cells similarly in the body. However, tissues have a complex machinery that allows tissue-specific optimization of local TH action that calls for the assessment of TH action in a tissue-specific manner. Here, we report the creation of a TH action indicator (THAI) mouse model to study tissue-specific TH action. The model uses a firefly luciferase reporter readout in the context of an intact transcriptional apparatus and all elements of TH metabolism and transport and signaling. The THAI mouse allows the assessment of the changes of TH signaling in tissue samples or in live animals using bioluminescence, both in hypothyroidism and hyperthyroidism. Beyond pharmacologically manipulated TH levels, the THAI mouse is sufficiently sensitive to detect deiodinase-mediated changes of TH action in the interscapular brown adipose tissue (BAT) that preserves thermal homeostasis during cold stress. The model revealed that in contrast to the cold-induced changes of TH action in the BAT, the TH action in this tissue, at room temperature, is independent of noradrenergic signaling. Our data demonstrate that the THAI mouse can also be used to test TH receptor isoform-specific TH action. Thus, THAI mouse constitutes a unique model to study tissue-specific TH action within a physiological/pathophysiological context and test the performance of thyromimetics. In conclusion, THAI mouse provides an in vivo model to assess a high degree of tissue specificity of TH signaling, allowing alteration of tissue function in health and disease, independently of changes in circulating levels of TH.

A de novo atypical ring sSMC(22) characterized by array CGH in a boy with cat-eye syndrome

BackgroundMicroduplications 22q11 have been characterized as a genomic duplication syndrome mediated by nonallelic homologous recombination between region-specific low-copy repeats. Here we report on a 19 years old boy with intellectual disability having an unexpected structurally complex ring small supernumerary marker chromosome (sSMC) originated from a larger trisomy and a smaller tetrasomy of proximal 22q11 harboring additional copies of cat eye syndrome critical regions genes.ResultsPrincipal clinical features were: anorectal and urogenital malformations, total anomalous pulmonary venous return with secundum ASD, hearing defect, preauricular pits, seizure and eczema. The proband also presented some rare or so far not reported clinical findings such as hyperinsulinaemia, severe immunodeficiency and grave cognitive deficits.Chromosome analysis revealed a mosaic karyotype with the presence of a small ring-like marker in 60% of cells. Array CGH detected approximately an 1,2 Mb single and a 0,2 Mb double copy gain of the proximal long arm of chromosome 22. The 1,3 Mb intervening region of chromosome 22 from centromere to the breakpoints showed no copy alteration. The karyotype of the patient was defined as 47,XY,+mar[60]/46,XY[40].ish idic r(22)(q11.1.q11.21) × 4.arr 22q11(17,435, 645-18,656,678) × 3,(17,598,642-17,799,783) × 4 dn.ConclusionsThe present report is the first one with a detailed description of clinical presentation in a patient carrying an atypical size ring sSMC (22) analyzed by array CGH. The specialty of the finding is emphasized by the fact that although the patient had a mosaic sSMC and the amplified region was smaller than in typical cat eye syndrome cases, the clinical presentation was severe.

Nemi kromoszóma-rendellenességek vizsgálata gyermekkorban

Introduction Early diagnosis of sex chromosome abnormalities is important because of prevention, family planning and optimal therapy. Aim Investigation of the relationship between phenotype, age at time of diagnosis and therapeutic options in sex chromosome aberrations. Method Processing data of 51 children with sex chromosome abnormalities who were diagnosed between 2009 and 2014 and examined at the 2nd. Department of Pediatrics, Semmelweis University, by the methods of anamnesis, family tree analysis, physical examination, karyotype analysis and fluorescent in situ hybridisation. Results 41% of the patients were diagnosed with Turner-, 18% with Klinefelter-, 10% with double-Y-, 6% with triple- and poly-X-syndrome, 19% with other gonadal dysgenesis and 6% with other abnormality. The average age at diagnosis: Turner- and Klinefelter-syndrome 10 years, other gonadal dysgenesis 9 years, 46,XX,t(X;10) 17 years, other abnormalities 1-2 years. Conclusions Numerical aberrations of the sex chromosomes are more common than structural aberrations. Klinefelter-, triple- and poly-X-syndromes are underdiagnosed in childhood. Early diagnosis of Turner-syndrome and other gonadal dysgenesis is necessary to optimise therapy and prevent associated diseases. This can be achieved by modern prenatal diagnostic methods and targeted activity of family pediatricians. Orv Hetil. 2018; 159(27): 1121-1128.

Elsődleges genetikai vizsgálat Prader–Willi-szindróma igazolására

Absztrakt: Bevezetes: A nemzetkozi szakirodalmi adatok alapjan az SNRPN genlocus promoter regiojanak DNS-metilacios vizsgalata jelenleg a legerzekenyebb es leghatekonyabb kezdeti lepes a Prader–Willi-szindroma-gyanus betegek genetikai vizsgalatakor. Celkitűzes: Celunk egy egyszerű, megbizhato, konnyen hozzaferhető, elsődlegesen diagnosztikus, DNS-metilacion alapulo eljaras kidolgozasa volt Prader–Willi-szindroma igazolasara. Modszer: Vizsgalatunk soran az altalunk modositott, koltseghatekony, metilacioszenzitiv, nagy felbontasu olvadaspont-elemzeses technikat hasonlitottuk ossze a leginkabb elterjedt, koltseges metilaciospecifikus multiplex ligatiofuggő probaamplifikacios technikaval. Klinikailag a Prader–Willi-szindroma tobb tunetet mutato 17 gyermek DNS-metilacios vizsgalatat vegeztuk el sajat tervezesű primerekkel: biszulfitszekvenalo polimeraz-lancreakcio, metilacioszenzitiv nagy felbontasu olvadaspont-elemzes es kontrollkent metilaciospecifikus multiplex ligatiofuggő probaamplifikacio tortent. Eredme...

Study of patterns of inheritance of premature ovarian failure syndrome carrying maternal and paternal premutations

BackgroundPremature ovarian failure / primary ovarian insufficiency (POF/POI) associated with the mutations of the FMR1 (Fragile-X Mental Retardation 1) gene belongs to the group of the so-called trinucleotide expansion diseases. Our aim was to analyse the relationship between the paternally inherited premutation (PIP) and the maternally inherited premutation (MIP) by the examination of the family members of women with POF, carrying the premutation allele confirmed by molecular genetic testing.MethodsMolecular genetic testing was performed in the patients of the 1st Department of Obstetrics and Gynecology with suspected premature ovarian failure. First we performed the southern blot analyses and for the certified premutation cases we used the Repeat Primed PCR.ResultsDue to POF/POI, a total of 125 patients underwent genetic testing. The FMR1 gene trinucleotide repeat number was examined in the DNA samples of the patients, and in 15 cases (12%) deviations (CGG repeat number corresponding to premutation or gray zone) were detected. In 6 cases out of the 15 cases the CGG repeat number fell within the range of the so-called gray zone (41–54 CGG repeat) (4.8%, 6/125), and the FMR1 premutation (55–200 CGG repeat) ratio was 7.2% (9/125). In 4 out of the 15 cases we found differences in both alleles, one was a premutation allele, and the other allele showed a repeat number belonging to the gray zone. Out of 15 cases, only maternal inheritance (MIP) was detected in 2 cases, in one case the premutation allele (91 CGG repeat number), while in the other case an allele belonging to the gray zone (41 CGG repeat number) were inherited from their mothers. In 10 out of 15 cases, the patient inherited the premutation allele only from the father (PIP). In 5 out of the 10 cases (50%) the premutation allele was inherited from the father, and the repeat number ranged from 55 to 133. Out of 125 cases, 9 patients had detectable cytogenetic abnormalities (7.2%).ConclusionsThe RP-PCR method can be used to define the smaller premutations and the exact CGG number. Due to the quantitative nature of the RP-PCR, it is possible to detect the mosaicism as well.