Acute megakaryoblastic leukemia with trisomy 3 and CBFA2T3::GLIS2: A case report.

Non-Down-syndrome-related acute megakaryoblastic leukemia (non-DS-AMKL) is a rare form of leukemia that can present with a variety of initial symptoms, including fever, rash, bruising, bleeding, or other more clinically challenging symptoms. Herein, we describe a 19-month-old female patient who presented with left lower extremity pain and language regression who was diagnosed with AMKL, not otherwise specified (NOS), on the basis of peripheral blood and bone marrow analysis, as well as cytogenetic and molecular diagnostic phenotyping. Of note, in addition to this patient's karyotype showing trisomy 3, a fusion between CBFA2T3 (core-binding factor, alpha subunit 2, translocated to, 3) on chromosome 16 and GLIS2 (GLIS family zinc finger protein 2), also on chromosome 16, was observed. Patients with AMKL who have trisomy 3 with CBFA2T3::GLIS2 fusions are rare, and it is not known if the co-occurrence of these abnormalities is coincidental or biologically related. This highlights the continued need for further expansion of genetic testing in individuals with rare disease to establish the groundwork for identifying additional commonalities that could potentially be used to identify therapeutic targets or improve prognostication.

Pediatric acute myeloid leukemia with t(7;21)(p22;q22).

The t(7;21)(p22;q22) resulting in RUNX1-USP42 fusion, is a rare but recurrent cytogenetic abnormality associated with acute myeloid leukemia (AML) and myelodysplastic syndromes. The prognostic significance of this translocation has not been well established due to the limited number of patients. Herein, we report three pediatric AML patients with t(7;21)(p22;q22). All three patients presented with pancytopenia or leukopenia at diagnosis, accompanied by abnormal immunophenotypic expression of CD7 and CD56 on leukemic blasts. One patient had t(7;21)(p22;q22) as the sole abnormality, whereas the other two patients had additional numerical and structural aberrations including loss of 5q material. Fluorescence in situ hybridization analysis on interphase cells or sequential examination of metaphases showed the RUNX1 rearrangement and confirmed translocation 7;21. Genomic SNP microarray analysis, performed on DNA extracted from the bone marrow from the patient with isolated t(7;21)(p22;q22), showed a 32.2 Mb copy neutral loss of heterozygosity (cnLOH) within the short arm of chromosome 11. After 2-4 cycles of chemotherapy, all three patients underwent allogeneic hematopoietic stem cell transplantation (HSCT). One patient died due to complications related to viral reactivation and graft-versus-host disease. The other two patients achieved complete remission after HSCT. Our data displayed the accompanying cytogenetic abnormalities including del(5q) and cnLOH of 11p, the frequent pathological features shared with other reported cases, and clinical outcome in pediatric AML patients with t(7;21)(p22;q22). The heterogeneity in AML harboring similar cytogenetic alterations may be attributed to additional uncovered genetic lesions.

A Novel Homozygous Deletion within the FRY Gene Associated with Nonsyndromic Developmental Delay.

The role of autosomal recessive (AR) variants in clinically heterogeneous conditions such as intellectual disability and developmental delay (ID/DD) has been difficult to uncover. Implication of causative pathogenic AR variants often requires investigation within large and consanguineous families, and/or identifying rare biallelic variants in affected individuals. Furthermore, detection of homozygous gene-level copy number variants during first-line genomic microarray testing in the pediatric population is a rare finding. We describe a 6.7-year-old male patient with ID/DD and a novel homozygous deletion involving the FRY gene identified by genomic SNP microarray. This deletion was observed within a large region of homozygosity on the long arm of chromosome 13 and in a background of increased low-level (2.6%) autosomal homozygosity, consistent with a reported common ancestry in the family. FRY encodes a protein that regulates cell cytoskeletal dynamics, functions in chromosomal alignment in mitosis in vitro, and has been shown to function in the nervous system in vivo. Homozygous mutation of FRY has been previously reported in 2 consanguineous families from studies of autosomal recessive ID in Middle Eastern and Northern African populations. This report provides additional supportive evidence that deleterious biallelic mutation of FRY is associated with ID/DD and illustrates the utility of genomic SNP microarray detection of low-level homozygosity.

Multiple Congenital Anomalies and Global Developmental Delay in a Patient with Interstitial 6q25.2q26 Deletion: A Diagnostic Odyssey.

Interstitial deletions involving 6q25 are rare chromosomal abnormalities associated with distinctive phenotypic features. We describe a 9-year-old boy who was followed from his infancy due to his multiple congenital anomalies and complex medical history. Over the years, a number of diagnoses were considered including Cornelia de Lange syndrome, Rubinstein-Taybi syndrome, as well as "a novel genetic disorder." Various genetic tests, including a BAC-based array-CGH analysis, were reported as normal. Recently, a SNP-based microarray analysis was performed and showed an 11.1-Mb deletion from 6q25.2 to 6q26, including ARID1B and ZDHHC14. Recent literature suggests that the 6q25 deletion syndrome is a recognizable entity characterized by growth delay, developmental disabilities, microcephaly, hearing loss, and variable other malformations including cleft palate. These features overlap with those of Coffin-Siris syndrome, which is caused by deletions and loss-of-function mutations of ARID1B. Retrospectively, this patient has features resembling both Coffin-Siris and 6q25 microdeletion syndromes.

Optical genome mapping reveals balanced and unbalanced genetic changes associated with tumor-forming potential in an early-stage prostate cancer epithelial subline (M2205).

BACKGROUND: Identifying cytogenetic changes in tumors can aid in diagnosis/prognosis and disease management. Complete cytogenetic characterization has historically required a multimethod/time-consuming approach. Optical genome mapping (OGM) offers a potential solution to this challenge by detecting both balanced and unbalanced abnormalities in a single assay. METHODS: Genetic changes acquired with tumor-forming potential in a prostate xenograft subline [M2205] (derived from a Black male) that were detected using cytogenetic versus OGM analyses were compared to assess the utility of OGM for analyzing solid tumors. RESULTS: Cytogenetic/OGM concordance was noted for (a) copy number gains (16, 1p, 3q, 5q, 7p, 8q, 9q, 11p, 11q, 15q, 20q), (b) copy number losses (Y, 3p, 4p, 6p, 7p, 9p, 11q), and (c) structural changes, including multibreak rearrangements. Discordance was noted for two structural findings, both of which had breakpoints localized to repetitive sequences. The OGM studies identified new findings and confirmed/further characterized 8q24 structural abnormalities. It also detected genes gained/disrupted in the 8q24 region (e.g., MYC, DEPTOR, and EXT1); but recognizing a jumping translocation required cytogenetic analyses. CONCLUSION: These results support using OGM as a tool to analyze solid tumors in clinical/research settings. Moreover, this OGM analysis expanded the characterization of cytogenetic changes present in the M2205 subline, including alterations associated with tumors from Black males diagnosed with prostate cancer.

Severe Graft-Versus-Host Disease Following Solid-Organ Transplant Confirmed by Chimerism Studies and Cytogenetic Analyses.

Graft-versus-host disease is an uncommon complication of solid-organ transplant and is associated with a high rate of mortality. Here, we describe a female patient with primary biliary cholangitis who developed graft-versus-host disease following an orthotopic liver and renal allotransplant from a deceased male donor. Systemic donor lymphoid chimerism is one of several important findings to confirm a diagnosis of graft-versus-host disease after solid-organ transplant, along with clinical and histologic findings. In this case, cytogenetic analyses and chimerism studies performed on blood, blood components, and bone marrow specimens obtained at several timepoints supported the diagnosis of graft-versus-host disease and demonstrated sustained near-complete donor engraftment of the lymphoid compartment. This case report illustrates the utility of chimerism testing to rapidly diagnose this serious condition in patients who have received a solid-organ transplant.

Chronic myelomonocytic leukemia with ETV6-ABL1 rearrangement and SMC1A mutation.

Chronic myelomonocytic leukemia (CMML) is a rare malignant neoplasm of the blood-forming cells in bone marrow characterized by persistent monocytosis. Although most patients with CMML show clonal genetic aberrations, there is no known cytogenetic or molecular genetic finding that is specific to CMML. We report a patient who had a clinical and morphological presentation consistent with CMML. The genetic work-up showed an ETV6-ABL1 fusion consequent to a 9;12 translocation, and a missense mutation in SMC1A (c.1757G>A, p.Arg586Gln). The SMC1A mutations are recurrent, albeit rare, in myeloid malignancies, without an established clinical significance in CMML. ETV6-ABL1 fusion is a rare but recurrent genetic aberration found in various hematologic malignancies involving both the lymphoid and myeloid lineage, but to the best of our knowledge, CMML is an exceptionally rare presentation of ETV6-ABL1 rearranged neoplasm. ETV6-ABL1 fusion is often formed through complex rearrangements, and usually cryptic by routine G-banded chromosome analysis. The diseases associated with this rearrangement generally have an aggressive course, hence detecting or excluding this rearrangement during diagnostic work-up is critical for treatment planning.

Identification of parental chromosomes involved in translocations BCR-ABL, t(9;22) and PML-RARA, t(15;17).

Cells of blood and bone marrow often exhibit a genome- or ploidywise organization of the two haploid sets, representing apparently maternal and paternal chromosomes in interphase nuclei and in metaphase spreads. This provides the opportunity to perform "genomic karyotyping." Such application of karyotyping may indicate whether two chromosomes involved in a translocation are both maternal, both paternal, or intermingled, i.e., one maternal and the other paternal (we refer to this as mixed). The parental origin for these translocations likely has profound differences and implications in disease expression and response to treatments, making such information very important to personalized medicine. In this mini-review, we present our observations from specimens with translocations BCR-ABL, t(9;22) and PML-RARA, t(15;17). About 20% metaphases of these specimens indicated ploidywise organization and were amenable to genomic karyotyping analysis. Fluorescence in situ hybridization (FISH) probes for BCR-ABL translocation suggest a close approximation of the HSA 9 and 22, as control values for false-positive signals run from approximately 5-10%. Given a ploidywise distribution of the maternal and paternal sets of chromosomes, it would be expected that the chromosomes involved in the translocation t(9;22) would more often belong to one of the two genomes, either maternal or paternal. Contrastingly, HSA 15 and 17 are not considered as spatially close to each other and therefore an intragenomic involvement would be rarer for translocation t(15;17). In 14 out of the 21 (66.6%) specimens with informative metaphases, the chromosomes involved in the translocation BCR-ABL were restricted to one of the two genomes--either maternal or paternal. In cases of translocation PML-RARA only 4 out of 21 (19.1%) specimens indicated an intragenomic involvement. These simple yet informative analyses of cancer-related translocations show profound underlying genomic origins and lend support to genomic karyotyping.