Journal of the Association of Genetic Technologists最新文献

Objectives: The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system is an RNA-guided DNA targeting platform widely known for its application in genome editing. Originally derived from the bacterial and archaebacterial defense mechanism against phage infection, it has since been studied and utilized for its potential as a genetic engineering tool and as a therapeutic agent. The Cas9 protein in its standard form induces double-stranded breaks (DSBs) in the target dsDNA sequence; however, modifications of the Cas9 protein have allowed for single-stranded breaks (SSBs) and even epigenetic modifications of gene expression. In comparison with previous methods including RNA interference, Zinc Finger Nucleases, and TAL Effector Nucleases, CRISPR is cheaper, more easily customized, and has a higher fidelity to its target site with fewer off-target effects. Consequently, CRISPR has become a central gene editing technique in a broad variety of research settings, with great potential for applications in human health. In this review, we offer an overview of CRISPR's mechanism of action and recent advancements in the application of CRISPR, as well as discuss literature pertinent to CRISPR applications to human health including many exciting prospective treatments for serious pathologies.

Objectives: Acute myeloid leukemia may present with significant dysmyelopoiesis within the peripheral blood smear and bone marrow aspirate. In the setting of Vitamin B12 deficiency, proliferation of a clonal population of malignant cells can become impaired, masking an underlying myelodysplastic or leukemic process. Typically, the cautionary tale warns against diagnosing acute myeloid leukemia before ruling out Vitamin B12 deficiency. Here we describe a patient who initially presented with pancytopenia and Vitamin B12 deficiency who, upon supplementation, developed overt acute myeloid leukemia. This case will highlight the importance of cytogenetic and molecular studies as essential diagnostic tools in patients with unique presentations.

Objectives: A 19-year-old male with a history of irritable bowel syndrome presented with progressive fatigue, periorbital petechiae, and abdominal pain for 2-3 weeks. The peripheral blood smear showed leukocytosis and circulating blasts. Elevated PT, PTT, and FDP with normal fibrinogen were found in the DIC panel workup. Abdominal CT suggested splenomegaly. A bone marrow biopsy revealed sheets of monotonous agranular monoblasts nearly completely replaced the hematopoietic elements. Chromosome analysis depicted an abnormal male karyotype with a t(9;11)(p22;q23) in all metaphase cells examined. Four cells showed, in addition, two 8q isochromosomes. FISH analysis was utilized with the MYC (8q24.21) probe from Abbott and the KMT2A (11q23), those of which showed gain on MYC and evidence of KMT2A. These findings correlate with the concurrent conventional cytogenetic findings and were described as nuc ish(MYCx4~9)[182/200],(KMT2Ax2)(5'KMT2A sep 3'KMT2Ax1)[181/200]. Complex karyotypes are associated with poor prognosis. Although only a few pediatric cases exist in the literature, the presence of additional abnormalities put this finding as a poor prognostic marker in AML. Correlation with other clinical data was indicated.

Objectives: Optical Genome Mapping (OGM) has emerged as a very powerful technology to diagnose in a single step a large variety of chromosomal abnormalities with high accuracy, at an unprecedented resolution, and in a time- and cost-effective way. A few recent studies provided a proof-of-principle that OGM can replace traditional cytogenomic assays (karyotyping, FISH, and SNP-arrays) in constitutional studies and the evaluation of hematologic disorders. OGM not only identified abnormalities previously diagnosed by standard methods, it highlighted the structural complexity of some rearrangements and uncovered novel findings with potential diagnostic, prognostic and therapeutic significance. While OGM still seems to have some technical and diagnostic limitations that require fine-tuning and improvement, it has so far shown so many promising advantages that future routine use heralds a revolutionary era in next-generation cytogenomic analysis.Keywords: Optical Genome Mapping, cytogenetic diagnosis, chromosome abnormalities detection, cancer cytogenetics, constitutional chromosome aberrations, cytogenomic variation, structural variants (SVs), copy number variants (CNVs)

Objectives: Atypical chronic myeloid leukemia, BCR-ABL1-negative (aCML), is a rare myelodysplastic/myeloproliferative neoplasm with heterogeneous clinical and genetic features, a high rate of transformation to acute myeloid leukemia (AML), and poor survival rate. The diagnosis of aCML is a diagnosis of exclusion and requires the fulfillment of strict diagnostic criteria. Until recently, there were no distinctive cytogenetic or molecular abnormalities for aCML adding to the diagnostic challenge. We present a case of aCML and highlight the pertinent clinical, morphological, and genetic features required for the diagnosis.

Objectives: Monoclonal B-cell lymphocytosis (MBL) is a light-chain restricted proliferation of mature B cells fewer than 5000 cells/μL without additional clinical or hematologic abnormalities. Sibling studies of individuals genetically susceptible to chronic lymphocytic leukemia (CLL) first identified monoclonal B cells in otherwise healthy persons, and studies show a 3% to 14% prevalence for MBL in persons over 40 years of age. Non-CLL-type MBL accounts for less than 20% of all MBL cases, and its progression is incompletely characterized. Here we present the case of an 85-year-old man with CD5-, CD19+, CD20 bright, and lambda-restricted lymphoid cells whose immunophenotypic findings are suggestive for a precursor lesion to marginal zone lymphoma (MZL). Karyotyping showed monosomy 21 without additional cytogenetic changes in three of the 35 cells examined. Monosomy 21 as a sole abnormality in CLL has been detected in just 11 cases between 1984 and 2003. As a sole abnormality in splenic and nodal marginal zone lymphoma, only three instances of monosomy 21 have been recorded on the Mitelman Database of Chromosome Aberrations and Gene Fusions in Cancer. The significance of monosomy 21 as a marker for oncogenesis remains unclear.

Objectives: Objective: Host genetics can influence susceptibility to Chlamydia trachomatis infection. This study examined two genetic variants in human protein disulfide isomerase A2 (PDIA2), a member of a family of protein chaperones that participate in the chlamydial life cycle. Methods: A total of 278 male and female subjects, positive or negative for C. trachomatis infection, were genotyped for PDIA2 polymorphisms (rs400037 and rs419949) using real-time PCR and pyrosequencing. Results: There was a significant odds ratio of 8.21 (95% CI: 1.77-38.16) for rs400037 and 9.89 (95% CI: 1.19-82.10) for rs419949, for the AA genotypes. Conclusion: This indicates that individuals with the PDIA2 AA genotypes have significantly increased susceptibility to C. trachomatis infection as compared to the other PDIA2 genotypes (GG, GA). This correlation may be explained by an interactive role of host protein disulfide isomerases in the attachment and entry of C. trachomatis into cells.

Objectives: Noonan syndrome (NS) is a relatively common autosomal dominant disorder with characteristic features and molecular alterations. The most common recurrent alteration is in the PTPN11 gene, a proto-oncogene that encodes a cytoplasmic receptor tyrosine phosphatase and helps regulate kinase activity and control cell survival and replication. Mutations in this gene can increase the risk for the development of multiple different malignancies, particularly hematopoietic. Here we present a case of NS with a PTPN11 mutation demonstrating the classic presentation of Noonan syndrome as well as the expected clinical follow-up.

Objectives: We report a 74-year-old male whose bone marrow morphology, flow cytometry, MRI and serum electrophoresis showed evidence of plasma cell myeloma. Chromosome analysis of the bone marrow showed an abnormal karyotype, described as 51~53,XY,+3,+5,t(8;14)(q24 .1;q32),+9,+11,+15,+19,+21[cp6]/46,XY[14]. The t(8;14)(q24.1;q32) is mainly seen in Burkitt lymphoma but it can also be seen in plasma cell myeloma usually with the context of a complex karyotype. Based on the Mitelman database the involvement of C-MYC is usually seen in late tumor progression in plasma cell myeloma as a secondary rearrangement, usually during clonal evolution and divergence and is associated with a significantly decreased survival. Our case pinpoints the involvement of MYC abnormalities in plasma cell myeloma as well as the importance of cytogenetics as a tool to manage and monitor plasma cell myeloma cases.

Objectives: We report on a rare case of B-cell prolymphocytic leukemia (B-PLL) in a patient with a history of chronic lymphocytic leukemia (CLL) that showed a novel translocation t(10;22)(q21;q11.22) and an interstitial deletion of 11q14.1-q23.3 in 2017. The chromosome microarray analysis (CMA) confirmed the 11q22 deletion and revealed a small interstitial deletion of IGL gene. In 2018, the patient presented with worsening lymphocytosis, anemia and thrombocytopenia. The peripheral blood smear revealed an increased prolymphocyte population, which comprised 60.4% of lymphoid cells, establishing a diagnosis of B-cell prolymphocytic leukemia. The CMA and G-banded chromosome analysis showed one additional aberration in the form of 1q gain translocated onto the other homologue 22. These findings suggested clonal evolution of CLL to B-PLL. The most common translocation involving immunoglobulin lambda chain (IGL) in CLL is the t(18;22), followed by t(8;22) and (11;22). An evolution to B-PLL occurs in most cases without gaining additional aberrations. Here, we report for the first time a novel translocation involving IGL with chromosome 10q21 and one 1q gain occurring in a patient with CLL that transformed to B-PLL. Based on the disease progression and this newly developed cytogenetic aberration, our case supports the progressive nature of CLL in the presence of IGL deletion and suggests the pathological role of 1q gain in CLL transformation.