A large fraction of trisomy 12, 17p-, and 11q- CLL cases carry unidentified microdeletions of miR-15a/16-1.

Chronic lymphocytic leukemia (CLL) is the most common adult leukemia and is characterized by chromosomal aberrations including 13q, 11q, and 17p deletions and a trisomy of chromosome 12 (T12). 13q deletions are often associated with 11q and 17p deletions in aggressive cases. Conversely, T12 CLLs show a variable prognosis, and association with 13q deletions is uncommon. The miR-15a/16-1 cluster is the functional target of 13q deletions, leading to BCL2 overexpression. Chromosomal aberrations in CLL are associated with prognosis, and their identification is carried out by fluorescence in situ hybridization (FISH). Since standard FISH only detects large deletions, we investigated the presence of undetected microdeletions targeting miR-15a/16-1 in CLL cases. We found that ∼34% of CLL samples show an unreported loss of the miR-15a/16-1 locus regardless of their cytogenetic profile. Interestingly, 15 out of 39 (∼39%) of all CLLs with T12, carry microdeletions of miR-15a/16-1, indicating that, in patients with T12, miR-15a/16-1 are mostly inactivated by microdeletions. In addition, ∼40% of CLL cases bearing T12, 17p-, and 11q- showed unidentified microdeletions of miR-15a/16-1, suggesting that miR-15a/16-1 loss cooperates with such chromosomal alterations in CLL. These data may have clinical relevance for the successful stratification of patients for treatment.

Drug-microenvironment perturbations reveal resistance mechanisms and prognostic subgroups in CLL.

The tumour microenvironment and genetic alterations collectively influence drug efficacy in cancer, but current evidence is limited and systematic analyses are lacking. Using chronic lymphocytic leukaemia (CLL) as a model disease, we investigated the influence of 17 microenvironmental stimuli on 12 drugs in 192 genetically characterised patient samples. Based on microenvironmental response, we identified four subgroups with distinct clinical outcomes beyond known prognostic markers. Response to multiple microenvironmental stimuli was amplified in trisomy 12 samples. Trisomy 12 was associated with a distinct epigenetic signature. Bromodomain inhibition reversed this epigenetic profile and could be used to target microenvironmental signalling in trisomy 12 CLL. We quantified the impact of microenvironmental stimuli on drug response and their dependence on genetic alterations, identifying interleukin 4 (IL4) and Toll-like receptor (TLR) stimulation as the strongest actuators of drug resistance. IL4 and TLR signalling activity was increased in CLL-infiltrated lymph nodes compared with healthy samples. High IL4 activity correlated with faster disease progression. The publicly available dataset can facilitate the investigation of cell-extrinsic mechanisms of drug resistance and disease progression.

Mosaic Trisomy 12: Prenatal Diagnosis at Amniocentesis and Molecular Genetic Analysis on Fetal Tissues.

Background: Mosaic trisomy 12 is a genetic condition with few cases diagnosed prenatally and postnatally. Phenotypic variability is wide ranging from normal patients to severe congenital anomalies. Case report: A 35-year-old woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Prenatal ultrasound was negative. Cultured amniocytes revealed a karyotype of 47,XX,+12/46,XX. Parents opted for termination of pregnancy at 22 weeks. Postmortem revealed dysmorphic face; hands with broad thumbs and incomplete transverse palmar creases; partial anomalous pulmonary venous return, intestinal malrotation, and bicornuate uterus. Histologically, no anomalies were identified. Cytogenetic analyses on fetal tissues detected mosaic trisomy 12 in thymus, lung, brain, kidney, placenta, and cord blood. Discussion/Conclusion: We report a new case of mosaic trisomy 12 with non-lethal morphological findings not previously described. Although prenatal ultrasound may be negative, genetic counseling should consider minor abnormalities and widespread presence of trisomic cell lines in various internal organs.

A rare case of postnatal mosaic trisomy 12 with severe congenital heart disease and literature review.

Trisomy 12 is a rare autosomal aneuploidy. All postnatally diagnosed individuals with trisomy 12 have been mosaic for this chromosome abnormality. We herein report an infant girl presented at 2 weeks of age with severe congenital heart defect, tracheobronchomalacia, and dysmorphic features. All of the dysmorphic features of this patient fit into the known phenotype spectrum of mosaic trisomy 12, although this patient uniquely presented with macrocephaly. Tracheo-bronchomalacia has been described once previously but had a significant impact on this patient's clinical course. The patient passed away at 2-month-old due to cardiac and respiratory complications. Chromosomal single nucleotide polymorphism (SNP) microarray analysis on a peripheral blood sample from the patient revealed trisomy 12 in approximately 50% of cells. Concurrent fluorescence in situ hybridization analysis of uncultured blood cells detected a comparable level of trisomy 12 mosaicism. Compared to conventional cytogenetics, SNP microarray examines all nucleated cells without sampling bias, has an increased power to estimate mosaicism level, and can provide a quick assessment of the underlying mechanism. Here we demonstrate the utilization of SNP microarray in the clinical diagnosis of those once considered rare disorders but might have been missed by conventional cytogenetic techniques.

Four children with postnatally diagnosed mosaic trisomy 12: Clinical features, literature review, and current diagnostic capabilities of genetic testing.

Children or adults with mosaic trisomy 12 diagnosed postnatally are extremely rare. Only a small number of patients with this mosaicism have been reported in the literature. The clinical manifestation of mosaic trisomy 12 is variable, ranging from mild developmental delay to severe congenital anomaly and neonatal death. The trisomy 12 cells are not usually able to be detected by phytohemagglutinin stimulated peripheral blood chromosome analysis. The variability of phenotypes and the limited number of patients with this anomaly pose a challenge to predict the clinical outcomes. In this study, we present the phenotypes and laboratory findings in four patients and review the 11 previously reported patients with mosaic trisomy 12 diagnosed postnatally, as well as 11 patients with mosaic trisomy 12 diagnosed prenatally. The findings of this study provide useful information for laboratory diagnosis and clinical management of these patients.

Mosaic Trisomy 12 Associated with Overgrowth Detected in Fibroblast Cell Lines.

Mosaic trisomy 12 is a rare anomaly, and only 9 cases of live births with this condition have been reported in the literature. The clinical phenotype is variable, including neuropsychomotor developmental delay, congenital heart disease, microcephaly, cutaneous spots, facial asymmetry, prominent ears, hypotonia, retinopathy, and sensorineural hearing loss. A 2-year-old female presented with neuropsychomotor developmental delay, prominent forehead, dolichocephaly, patchy skin pigmentation, and unexpected overgrowth at birth. Cytogenetic analysis of her peripheral blood showed normal results, suggesting the presence of a chromosomal alteration in other tissues. Further studies using G-banding and FISH performed on fibroblasts from both hyper- and hypopigmented regions identified a 47,XX,+12/46,XX karyotype. To the best of our knowledge, no patients with mosaic trisomy 12 associated with overgrowth have been reported to date. Congenital overgrowth and neonatal overgrowth have been frequently linked to Pallister-Killian syndrome (PKS; OMIM 601803). This case suggests the possibility of an association of genes present in the 12p region with fetal overgrowth, considering that chromosomal duplications could lead to an increase in the production of aberrant transcripts and disturbing gene dosage effects. This case highlights the importance of cytogenetic analysis in different tissues to provide relevant information to the specific genotype/phenotype correlation.

Activation-induced deaminase and its splice variants associate with trisomy 12 in chronic lymphocytic leukemia.

Activation-induced cytidine deaminase (AID) is a mutator enzyme essential for somatic hypermutation (SHM) and class switch recombination (CSR) during effective adaptive immune responses. Its aberrant expression and activity have been detected in lymphomas, leukemias, and solid tumors. In chronic lymphocytic leukemia (CLL) increased expression of alternatively spliced AID variants has been documented. We used real-time RT-PCR to quantify the expression of AID and its alternatively spliced transcripts (AIDΔE4a, AIDΔE4, AIDivs3, and AIDΔE3E4) in 149 CLL patients and correlated this expression to prognostic markers including recurrent chromosomal aberrations, the presence of complex karyotype, mutation status of the immunoglobulin heavy chain variable gene, and recurrent mutations. We report a previously unappreciated association between higher AID transcript levels and trisomy of chromosome 12. Functional analysis of AID splice variants revealed loss of their activity with respect to SHM, CSR, and induction of double-strand DNA breaks. In silico modeling provided insight into the molecular interactions and structural dynamics of wild-type AID and a shortened AID variant closely resembling AIDΔE4, confirming its loss-of-function phenotype.

Mutational and cytogenetic analyses of 188 CLL patients with trisomy 12: A retrospective study from the French Innovative Leukemia Organization (FILO) working group.

Trisomy 12 (tri12) is the second most frequent chromosomal aberration (15%-20%) in chronic lymphocytic leukemia (CLL). Tri12 confers an intermediate prognosis but is a heterogeneous entity. We examined whether additional mutational or chromosomal alterations might impact tri12 patient outcomes. This retrospective study, carried out by the French Innovative Leukemia Organization, included 188 tri12 patients with comprehensive information on immunoglobulin heavy chain (IGHV) gene status, karyotypic/FISH abnormalities, and NOTCH1, TP53, SF3B1, and MYD88 mutations. The main cytogenetic abnormalities associated with tri12 were del(13q) (25%), additional trisomies (14%) (including tri19 (10%) and tri18 (4%)), 14q32 translocations (10%), del(17p) (6.5%), del(14q) (4%), and del(11q) (4%). Unmutated (UM) IGHV, NOTCH1, and TP53, mutations were identified in respectively 66%, 25%, and 8.5% of cases. Multivariate analyses showed that additional trisomies (HR = 0.43, 95% CI = 0.23-0.78, P = .01) were associated with a significantly longer time to first treatment in Binet stage A patients and with a lower risk of relapse (HR = 0.37, 95% CI = 0.15-0.9, P = .03) in the overall tri12 population. Binet stage B/C, TP53 disruption, and UM IGHV status were associated with a shorter time to next treatment, while Binet stage B/C (HR = 4, 95% CI = 1.6-4.9, P = .002) and TP53 disruption (HR = 5, 95% CI = 1.94-12.66, P = .001) conferred shorter overall survival in multivariate comparisons. These data indicate that additional cytogenetic and mutational abnormalities, and particularly additional trisomies, IGHV status, and TP53 disruption, influence tri12 patient outcomes and could improve risk stratification in this population.

Low CD23 expression correlates with high CD38 expression and the presence of trisomy 12 in CLL.

Chronic lymphocytic leukemia (CLL) is characterized by a neoplastic B-cell population coexpressing CD5 and CD23; however, the expression of CD23 is variable. In human, two isotypes of CD23 have been identified and related to different functions. The aim of our study was to investigate the relative expression of the two CD23 isotypes in CLL and find possible correlation with other prognostic factors. The expression of CD23 isotypes was analyzed in 54 cases of CLL by polymerase chain reaction (PCR) and quantitative real-time PCR. The immunophenotype of CLL cells was characterized by flow cytometry. We demonstrated a higher CD23a than CD23b expression of CLL cells. Our results also revealed two subsets of CLL cases with a distinct CD23 isotype expression pattern. Thirty-two percent of the cases (group CLL1) showed both low mRNA level of CD23 isotypes and high protein levels of CD20 and CD38 in contrast to group CLL2 with high CD23 mRNA levels. By correlating these results to the presence of prognostic factors determined by fluorescence in situ hybridization, we found that the majority of the cases of group CLL1 (14/17) carried trisomy 12. In summary, our results confirm a high CD23a/CD23b ratio of the CLL cells and demonstrate that in a subset of CLL cases, low CD23 expression together with high CD20 and CD38 expressions may serve as a surrogate for trisomy 12. Copyright © 2015 John Wiley & Sons, Ltd.

Clinical features of trisomy 12 mosaicism-Report and review.

Trisomy 12 mosaicism is a rare condition. Herein, we report a patient with mosaic trisomy 12 who was conceived by in vitro fertilization. She presented with mild dysmorphic features at birth, including down-slanting palpebral fissures, a depressed and creased nasal bridge, and mild rhizomelic shortening of the limbs. She had age-appropriate development at 6 months of age, but displayed slightly more dysmorphic features than at birth. Chromosome analysis on peripheral blood revealed a normal female karyotype in 50 metaphases. A concurrent genomic microarray analysis showed trisomy 12 in about 25% of the specimen, which was also confirmed by fluorescence in situ hybridization analysis with the CEP12 probe. Our findings further delineate the clinical features in trisomy 12 mosaicism in liveborns and demonstrate the utility of genomic microarray analysis in identification of mosaic aneuploidies.

Anatomy of trisomy 12.

Trisomy 12 is a rare aneuploidy and fetuses with this defect tend to spontaneously abort. However, mosaicism allows this anomaly to manifest itself in live births. Due to the fact that mosaicism represents a common genetic abnormality, trisomy 12 is encountered more frequently than expected at a rate of 1 in 500 live births. Thus, it is imperative that medical practitioners are aware of this aneuploidy. Moreover, this genetic disorder may result from a complete or partial duplication of chromosome 12. A partial duplication may refer to a specific segment on the chromosome, or one of the arms. On the other hand, a complete duplication refers to duplication of both arms of chromosome 12. The combination of mosaicism and the variable duplication sites has led to variable phenotypes ranging from normal phenotype to Potter sequence to gross physical defects of the various organ systems. This article provides a review of the common anatomical variation of the different types of trisomy 12. This review revealed that further documentation is needed for trisomy 12q and complete trisomy 12 to clearly delineate the constellation of anomalies that characterize each genetic defect. Clin. Anat. 29:633-637, 2016. © 2016 Wiley Periodicals, Inc.

Spatial quantitation of FISH signals in diploid versus aneuploid nuclei.

Fluorescence in situ hybridization (FISH) is the most widely used molecular technique to visualize chromosomal abnormalities. Here, we describe a novel 3D modeling approach to allow precise shape estimation and localization of FISH signals in the nucleus of human embryonic stem cells (hES) undergoing progressive but defined aneuploidy. The hES cell line WA09 acquires an extra copy of chromosome 12 in culture with increasing passages. Both diploid and aneuploid nuclei were analyzed to quantitate the differences in the localization of centromeric FISH signals for chromosome 12 as it transitions from euploidy to aneuploidy. We employed superquadric modeling primitives coupled with principal component analysis to determine the 3D position of FISH signals within the nucleus. A novel aspect of our modeling approach is that it allows comparison of FISH signals across multiple cells by normalizing the position of the centromeric signals relative to a reference landmark in oriented nuclei. Using this model we present evidence of changes in the relative positioning of centromeres in trisomy-12 cells when compared with diploid cells from the same population. Our analysis also suggests a significant change in the spatial distribution of at least one of the FISH signals in the aneuploid chromosome complements implicating that an overall change in centromere position may occur in trisomy-12 due to the addition of an extra chromosome. These studies underscore the unique utility of our modeling algorithms in quantifying FISH signals in three dimensions.

Trisomy 12 compromises the mesendodermal differentiation propensity of human pluripotent stem cells.

Trisomy 12 is one of the most frequent chromosomal abnormalities in cultured human pluripotent stem cells (hPSCs). Although potential oncogenic properties and augmented cell cycle caused by trisomy 12 have been reported, the consequences of trisomy 12 in terms of cell differentiation, which is the basis for regenerative medicine, drug development, and developmental biology studies, have not yet been investigated. Here, we report that trisomy 12 compromises the mesendodermal differentiation of hPSCs. We identified sublines of hPSCs carrying trisomy 12 after their prolonged culture. Transcriptome analysis revealed that these hPSC sublines carried abnormal gene expression patterns in specific signaling pathways in addition to cancer-related cell cycle pathways. These hPSC sublines showed a lower propensity for mesendodermal differentiation in embryoid bodies cultured in a serum-free medium. BMP4-induced exit from the self-renewal state was impaired in the trisomy 12 hPSC sublines, with less upregulation of key transcription factor gene expression. As a consequence, the differentiation efficiency of hematopoietic and hepatic lineages was also impaired in the trisomy 12 hPSC sublines. We reveal that trisomy 12 disrupts the genome-wide expression patterns that are required for proper mesendodermal differentiation.

Gene Mutations Associated With Chronic Lymphocytic Leukemia (CLL) Among Saudi CLL Patients and Treatment Outcomes: A Single-Center Experience.

Background Chronic lymphocytic leukemia (CLL) starts in white blood cells in the peripheral blood (stages 0 and 1). In CLL, leukemia cells often build up slowly. Many gene mutations are associated with CLL, such as trisomy 12, 13q14 deletion, and 17q deletion. Due to the lack of patients' disease characteristics, gene mutations, and treatment outcomes data among Saudi patients, this study aimed to identify the relation between the gene mutations of CLL and the treatment in King Abdulaziz Medical City (KAMC), Riyadh. Methods This cross-sectional study used data from the BESTCare hospital information system. The study included all patients diagnosed with CLL and confirmed by flow cytometry in KAMC, Riyadh, between January 2010 and October 2020. The data included demographic information, mutation type or chromosome, present comorbidity, and type of treatment. Results The study included 100 CLL patients. According to different types of clusters of differentiation (CD), CD5 was positive in 84 (84%) patients, and 88 (88%) patients were positive for CD19. Cytogenetic remarkers were tested, revealing that 21 (21%) patients with trisomy 12 and 20 (20%) were positive for 13q14 deletion. Observation of patients' disease status based on the cytogenetic remarkers showed that out of 15 patients with trisomy, 12 (80%) had not progressed and were stable and alive. Out of 20 patients with 13q14 deletion, 16 (80%) were alive and 13 (65%) patients were stable. Conclusion CLL patients in KAMC, Riyadh, displayed trisomy 12, which is characterized by the worst prognosis of disease status, as the most frequently detected cytogenetic aberration followed by 13q deletion. However, most patients were stable and alive.

A case report of Pallister-Killian syndrome with an unusual mosaic supernumerary marker chromosome 12 with interstitial 12p13.1-p12.1 duplication.

Pallister-Killian syndrome (PKS) is a rare inherited disease with multiple congenital anomalies, profound intellectual disability, and the presence in the karyotype of sSMC - i(12)(p10). The frequency of PKS may be underestimated due to problems with cytogenetic diagnosis caused by tissue-specific mosaicism and usually a low percentage of peripheral blood cells containing sSMC. Such tissue-specific mosaicism also complicates a detailed analysis of the sSMC, which, along with the assessment of mosaicism in different tissues, is an important part of cytogenetic diagnosis in PKS. Unfortunately, a full-fledged diagnosis in PKS is either practically impossible or complicated. On the one hand, this is due to problems with the biopsy of various tissues (skin biopsy with fibroblast culture is most often used in practice); on the other - a low percentage of dividing peripheral blood cells containing sSMC, which often significantly complicates the analysis of its composition and organization. In the present study, a detailed analysis of sSMC was carried out in a patient with a characteristic clinical picture of PKS. A relatively high percentage of peripheral blood cells with sSMC (50%) made it possible to perform a detailed molecular cytogenetic analysis of de novo sSMC using chromosomal in situ suppression hybridization (CISS-hybridization), multicolor FISH (mFISH), multicolor chromosome banding (MCB), array CGH (aCGH), and quantitative real-time PCR (qPCR), and short tandem repeat (STR) - analysis. As a result, it was found that the sSMC is not a typical PKS derivative of chromosome 12. In contrast to the classical i(12)(p10) for PKS, the patient's cells contained an acrocentric chromosome consisting of 12p material. Clusters of telomeric repeats were found at the both ends of the sSMC. Furthemore, the results of aCGH and qPCR indicate the presence of interstitial 8.9 Mb duplication at 12p13.1-p12.1 within the sSMC, which leads to different representations of DNA from different segments of 12p within cells containing sSMC. The obtained data raise the question of the instability of the sSMC and, as a consequence, the possible presence of additional rearrangements, which, in traditional cytogenetic analysis of patients with PKS, are usually described as i(12)(p10).

Concurrent development of small lymphocytic lymphoma and lung cancer: A report of two cases and a review of the literature.

Small lymphocytic lymphoma (SLL) is a rare disease subtype which has the same morphological and immunophenotypic features as chronic lymphocytic leukemia (CLL) but does not demonstrate lymphocytosis and grows mainly in the lymph nodes and spleen. As with CLL, SLL patients tend to present with immune abnormalities, and are associated with an increased risk for developing second primary malignancies. We report here two cases of SLL who developed lung cancer concurrently. The biological and clinical features of these two patients were very similar to each other; they both developed SLL with trisomy 12 and lacked lymphocytosis or cytopenia. SLL cells involved nodal areas adjacent to lung adenocarcinoma which expressed PD-L1. One patient received immunochemotherapy including nivolumab and ipilimumab against lung cancer, and notably, transient deterioration of SLL occurred after the second cycle of immunochemotherapy along with the development of immune related adverse events. Immunohistochemical analysis of the SLL samples of the patient revealed that the tumor cells were positive for CTLA-4, suggesting that ipilimumab might have potentially induced the activation of SLL cells by blocking the inhibitory signal mediated by CTLA-4. These clinical findings indicate the potential biological relationship between SLL and lung cancer. According to these observations, we would like to draw attention to the possibility of deterioration of SLL when immune checkpoint inhibitors are used for the treatment of malignancies developed in SLL patients.

Pigmentary mosaicism as a recurrent clinical manifestation in three new patients with mosaic trisomy 12 diagnosed postnatally: cases report and literature review.

BACKGROUND: To date, only twenty-one cases diagnosed postnatally with mosaic trisomy 12 have been reported. The most frequent phenotypic manifestations are developmental delay, dysmorphic facial features, congenital heart defects, digital alterations, and pigmentary disorders. In the present report, detailed clinical and genetic profiles of three unrelated new patients with mosaic trisomy 12 are described and compared with previously reported cases. CASE PRESENTATION: In the present report, we include the clinical, cytogenetic, and molecular description of three Mexican patients diagnosed postnatally with mosaic trisomy 12. At phenotypic level, the three patients present with developmental delay, dysmorphic facial features, congenital heart defects and skin pigmentary anomalies. Particularly, patient 1 showed unique eye alterations as bilateral distichiasis, triple rows of upper lashes, and digital abnormalities. In patient 2 redundant skin, severe hearing loss, and hypotonia were observed, and patient 3 presented with hypertelorism and telecanthus. Hyperpigmentation with disseminated pigmentary anomalies is a common trait in all of them. The cytogenetic study was carried out under the strict criteria of analysis, screening 50-100 metaphases from three different tissues, showing trisomy 12 mosaicism in at least one of the three different tissues analyzed. With SNParray, the presence of low-level mosaic copy number variants not previously detected by cytogenetics, and uniparental disomy of chromosome 12, was excluded. STR markers allowed to confirm the absence of uniparental disomy as well as to know the parental origin of supernumerary chromosome 12. CONCLUSIONS: The detailed clinical, cytogenetic, and molecular description of these three new patients, contributes with relevant information to delineate more accurately a group of patients that show a heterogeneous phenotype, although sharing the same chromosomal alteration. The possibility of detecting mosaic trisomy 12 is directly associated with the sensitivity of the methodology applied to reveal the low-level chromosomal mosaicism, as well as with the possibility to perform the analysis in a suitable tissue.

An unusual case of chronic lymphocytic leukemia with trisomy 12 and t(14;18) and a favorable response to ibrutinib.

Chronic lymphocytic leukemia (CLL) is the most common type of adult leukemia. Chromosomal abnormalities are reported to play important roles in CLL pathogenesis and evolution, including deletions of 11q, 13q, 17p, and trisomy12, that are frequently observed and have a known prognostic value. Furthermore, the mutational status of the IGHV gene was reported as an independent prognostic marker in CLL impacting the choice of therapy. We herein, report an unusual presentation of a Lebanese CLL patient with two cytogenetic abnormalities: trisomy 12 and t(14;18)(q32;q21), along with an unmutated IGHV, displaying a favorable response to ibrutinib with a maintained complete remission.