[Prenatal diagnosis of a fetus with 15q11q13 complex duplication syndrome and a literature review].

OBJECTIVE: To explore the clinical features and genetic etiology of a fetus with 15q11q13 complex duplication syndrome. METHODS: A fetus diagnosed with 15q11q13 duplication syndrome at Ningbo Women and Children's Hospital on April 19, 2023 was selected as the study subject. Clinical data was collected, and the fetus was subjected to invasive prenatal diagnosis including G-banded karyotyping and chromosomal microarray analysis (CMA). Following the discovery of chromosomal duplication, trio-whole exome sequencing was carried out to exclude single base variants and confirm the parental original of the duplication. Optical genome mapping was also performed to delineate the structural arrangement of the duplication. Relevant literature was searched in the PubMed, Wanfang Medical Network and CNKI databases using "15q11q13", "duplication", "hexasomy" and "Six fold repetition" as the key words from January 1, 2000 to August 1, 2023 for a review of previously reported 15q11q13 hexasomy cases. This study was approved by the Ningbo Women & Children's Hospital (Ethics No. EC2020-048). RESULTS: The fetus was found to have a mosaicism karyotype of 48,X?,+mar,+idic(15)(q13)[33]/47,X?,+idic(15)(q13)[17]. CMA and trio-WES have all shown a six-fold duplication in the PWS/AS critical region (PWACR) at 15q11.2q13.2 and quadruple duplication of 15q13.2q13.3 region, which have derived from its mother and formed supernumerary marker chromosomes (SMCs). Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the 15q11.2q13.2 sixfold duplication was classified as pathogenic, whilst the 15q13.2q13.3 quadruple duplication was classified as variant of uncertain significance. Literature search has identified 11 cases of 15q11q13 duplication involving hexasomy of the PWACR, with all cases showing mental retardation, language delay and hypotonia, and most of them also had motor retardation, epilepsy and mild facial dysmorphism. CONCLUSION: Hexasomy for the PWACR combined with tetrasomy of 15q13.2q13.3 probably underlay the left hand polydactyly, polyhydramnios and intrauterine growth retardation in this fetus.

[A case report of Crohn's disease in a child with trisomy 8]. / ä¼´8å·æŸ“è‰²ä½“ä¸‰ä½“çš„å„¿ç«¥å ‹ç½—æ©ç— 1例报告.

The patient is a 12-year-old male who has experienced recurrent perianal abscesses for over 10 years, along with recurrent oral ulcers and deformities in the joints of hands and feet. Gastrointestinal endoscopy and capsule endoscopy revealed multiple ulcers in the digestive tract. Combined with his histopathological examinations, the patient was diagnosed with Crohn's disease. Whole exome sequencing and peripheral blood karyotype analysis indicated a karyotype of 47,XY,+8. The patient was treated with a "step-up" strategy. His clinical symptoms were under control, with significant improvement observed during endoscopic examination. This case suggests that early-onset inflammatory bowel disease may have genetic susceptibility, and when accompanied by other multi-system involvement, the possibility of chromosomal abnormalities, such as trisomy 8, should be considered and given due attention.

Single-cell multi-omics map of human fetal blood in Down syndrome.

Down syndrome predisposes individuals to haematological abnormalities, such as increased number of erythrocytes and leukaemia in a process that is initiated before birth and is not entirely understood1-3. Here, to understand dysregulated haematopoiesis in Down syndrome, we integrated single-cell transcriptomics of over 1.1 million cells with chromatin accessibility and spatial transcriptomics datasets using human fetal liver and bone marrow samples from 3 fetuses with disomy and 15 fetuses with trisomy. We found that differences in gene expression in Down syndrome were dependent on both cell type and environment. Furthermore, we found multiple lines of evidence that haematopoietic stem cells (HSCs) in Down syndrome are 'primed' to differentiate. We subsequently established a Down syndrome-specific map linking non-coding elements to genes in disomic and trisomic HSCs using 10X multiome data. By integrating this map with genetic variants associated with blood cell counts, we discovered that trisomy restructured regulatory interactions to dysregulate enhancer activity and gene expression critical to erythroid lineage differentiation. Furthermore, as mutations in Down syndrome display a signature of oxidative stress4,5, we validated both increased mitochondrial mass and oxidative stress in Down syndrome, and observed that these mutations preferentially fell into regulatory regions of expressed genes in HSCs. Together, our single-cell, multi-omic resource provides a high-resolution molecular map of fetal haematopoiesis in Down syndrome and indicates significant regulatory restructuring giving rise to co-occurring haematological conditions.

Genetic counseling of mosaicism for a duplication due to partial trisomy in a cell line with 46 chromosomes associated with a normal cell line at amniocentesis.

Genetic counseling of mosaicism for a duplication due to partial trisomy in a cell line with 46 chromosomes associated with a normal cell line at amniocentesis remains difficult because mosaic duplication due to partial trisomy has been reported to be associated with either normal or abnormal phenotype in prenatal diagnosis. This article makes a comprehensive review of the reported cases of mosaicism for a duplication due to partial trisomy in a cell line with 46 chromosomes associated with a normal cell line at amniocentesis and various counseling issues such as culture artefact, cytogenetic discrepancy between cultured and uncultured amniocytes and among various tissues, perinatal progressive decrease of the abnormal cell line and a possible favorable fetal outcome. The information provided is useful for obstetricians and genetic counselors during genetic counseling of the parents who wish to keep the babies under such a circumstance.

Low-level mosaic trisomy 14 at amniocentesis in a pregnancy associated with cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes, positive non-invasive prenatal testing for trisomy 14, perinatal progressive decrease of the trisomy 14 cell line and a favorable fetal outcome.

OBJECTIVE: We present low-level mosaic trisomy 14 at amniocentesis. CASE REPORT: A 37-year-old, gravida 2, para 1, woman underwent amniocentesis at 18 weeks of gestation because of advanced maternal age. This pregnancy was conceived by in vitro fertilization and embryo transfer (IVF-ET). Amniocentesis revealed a karyotype of 47,XX,+14 [4]/46,XX [27], consistent with 12.9% mosaicism for trisomy 14. Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed the result of arr (1-22, X) × 2 with no genomic imbalance. Prenatal ultrasound findings were unremarkable. She was referred for genetic counseling at 21 weeks of gestation and was offered expanded non-invasive prenatal testing (NIPT) which was positive for trisomy 14. At 24 weeks of gestation, she underwent repeat amniocentesis which revealed a karyotype of 47,XX,+14 [2]/46,XX [26], consistent with 7% mosaicism for trisomy 14. The parental karyotypes were normal. Simultaneous aCGH analysis on the DNA extracted from uncultured amniocytes revealed no genomic imbalance. Polymorphic marker analysis excluded uniparental disomy (UPD) 14. Interphase fluorescence in situ hybridization (FISH) analysis on 104 uncultured amniocytes detected no trisomy 14 cell. At 35 weeks of gestation, a 2315-g phenotypically normal baby was delivered. The umbilical cord and placenta had the karyotype of 46, XX (40/40 cells). aCGH analysis on the DNA extracted from peripheral blood and buccal mucosal cells at the age of three months revealed no genomic imbalance. The neonate was normal in phenotype and development during postnatal follow-ups. CONCLUSIONS: Low-level mosaic trisomy 14 at amniocentesis can be associated with cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes, perinatal progressive decrease of the trisomy 14 cell line and a favorable fetal outcome.

Mosaic distal 13q duplication due to mosaic unbalanced translocation of 46,XY,der(14)t(13;14)(q32.2;p13)/46,XY at amniocentesis in a pregnancy associated with a favorable fetal outcome, perinatal progressive decrease of the aneuploid cell line and cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes.

OBJECTIVE: We present mosaic distal 13q duplication due to mosaic unbalanced translocation 46,XY,der(14)t(13;14)(q32.2;p13)/46,XY at amniocentesis in a pregnancy associated with a favorable fetal outcome. CASE REPORT: A 37-year-old, gravida 2, para 0, woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 46,XY, add(14) (p13)[17]/46,XY[13] (56.6% mosaicism). Array comparative genomic hybridization (aCGH) analysis on the DNA extracted from cultured amniocytes revealed arr 13q32.2q34 × 2∼3, consistent with 45% mosaicism for distal 13q duplication. Repeat amniocentesis at 24 weeks of gestation revealed a karyotype of 46,XY,der(14)t(13;14)(q32.2;p13)[14]/46,XY[16] (46.6% mosaicism). The parental karyotypes were normal. aCGH analysis on the DNA extracted from uncultured amniocytes revealed arr 13q32.2q34 × 2.38, consistent with 30-40% mosaicism for distal 13q duplication. Interphase fluorescence in situ hybridization (FISH) analysis on uncultured amniocytes detected 22.8% (23/101 cells) mosaicism for distal 13q duplication. Prenatal ultrasound findings were unremarkable. At 39 weeks of gestation, a 3616-g phenotypically normal baby was delivered. The karyotypes of cord blood, umbilical cord and placenta were 46,XY,der(14)t(13;14)(q32.2;p13)[20]/46,XY[20] (50% mosaicism), 46,XY,der(14)t(13;14)(q32.2;p13)[14]/46,XY[26] (35% mosaicism) and 46,XY (40/40 cells) (0% mosaicism), respectively. When follow-ups at the age of 4½ months and the age of one year, the peripheral blood had the karyotype of 46,XY,der(14)t(13;14)(q32.2;p13)[18]/46,XY[22] (45% mosaicism). Interphase FISH analysis on buccal mucosal cells at the age of 4½ months revealed 2.7% (3/110 cells) mosaicism for distal 13q duplication, compared with 1% (1/100 cells) in the normal control. The neonate was normal in phenotype and development. CONCLUSIONS: Mosaic unbalanced translocation at amniocentesis can be associated with a favorable fetal outcome, perinatal progressive decrease of the aneuploid cell line and cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes.

Global analysis of gene expression in response to double trisomy loquat (Eriobotrya japonica).

Aneuploidy generally has severe phenotypic consequences. However, the molecular basis for this has been focused on single chromosomal dosage changes. It is not clear how the karyotype of complex aneuploidies affects gene expression. Here, we identified six different double-trisomy loquat strains from Q24 progenies of triploid loquat. The differences and similarities of the transcriptional responses of different double trisomy loquat strains were studied systematically via RNA-seq. The global modulation of gene expression indicated that both cis and trans-effects coordinately regulated gene expression in aneuploid loquat to some extent, and this coordinated regulation was determined by different gene functional groups. Aneuploidy can induce specific transcriptional responses on loquat chromosomes. The differentially expressed genes exhibited regional gene expression dysregulation domains along chromosomes. Furthermore, Aneuploidy could also promote the expression of genes with moderate and high in loquats. Our results provide new insights into the genome-wide transcriptional effects of karyotypes with complex aneuploidies.

Chromosome 9p trisomy increases stem cells clonogenic potential and fosters T-cell exhaustion in JAK2-mutant myeloproliferative neoplasms.

JAK2V617F is the most recurrent genetic mutation in Philadelphia-negative chronic Myeloproliferative Neoplasms (MPNs). Since the JAK2 locus is located on Chromosome 9, we hypothesized that Chromosome 9 copy number abnormalities may be a disease modifier in JAK2V617F-mutant MPN patients. In this study, we identified a subset of MPN patients with partial or complete Chromosome 9 trisomy (+9p patients), who differ from JAK2V617F-homozygous MPN patients as they carry three JAK2 alleles as well as three copies of all neighboring gene loci, including CD274, encoding immunosuppressive Programmed death-ligand 1 (PD-L1) protein. Investigation of the clonal hierarchy revealed that the JAK2V617F occurs first, followed by +9p. Functionally, CD34+ cells from +9p MPN patients demonstrated increased clonogenicity, generating a greater number of primitive colonies, due to high OCT4 and NANOG expression, with knock-down of these genes leading to a genotype-specific decrease in colony numbers. Moreover, our analysis revealed increased PD-L1 surface expression in malignant monocytes from +9p patients, while analysis of the T cell compartment unveiled elevated levels of exhausted cytotoxic T cells. Overall, here we identify a distinct novel subgroup of MPN patients, who feature a synergistic interplay between +9p and JAK2V617F that shapes immune escape characteristics and increased stemness in CD34+ cells.

Intracortical myelin across laminae in adult individuals with 47,XXX: a 7 Tesla MRI study.

47,XXX (Triple X syndrome) is a sex chromosome aneuploidy characterized by the presence of a supernumerary X chromosome in affected females and is associated with a variable cognitive, behavioral, and psychiatric phenotype. The effect of a supernumerary X chromosome in affected females on intracortical microstructure is currently unknown. Therefore, we conducted 7 Tesla structural MRI and compared T1 (ms), as a proxy for intracortical myelin (ICM), across laminae of 21 adult women with 47,XXX and 22 age-matched typically developing females using laminar analyses. Relationships between phenotypic traits and T1 values in 47,XXX were also investigated. Adults with 47,XXX showed higher bilateral T1 across supragranular laminae in the banks of the superior temporal sulcus, and in the right inferior temporal gyrus, suggesting decreases of ICM primarily within the temporal cortex in 47,XXX. Higher social functioning in 47,XXX was related to larger inferior temporal gyrus ICM content. Our findings indicate an effect of a supernumerary X chromosome in adult-aged women on ICM across supragranular laminae within the temporal cortex. These findings provide insight into the role of X chromosome dosage on ICM across laminae. Future research is warranted to further explore the functional significance of altered ICM across laminae in 47,XXX.

Surgery for hepatoblastoma in children with trisomy 18: a monocentric study.

PURPOSE: Recently, children with trisomy 18 have been receiving more active treatment for malignancies. We report herein seven cases complete resection was achieved, and discuss multidisciplinary treatment for hepatoblastoma in patients with trisomy 18. METHOD: The medical records of children with trisomy 18 who were treated at the study center between 2010 and 2023 were reviewed. RESULT: Six of 69 patients had hepatoblastoma development, and three of these underwent multidisciplinary treatment. In addition, 6 patients had been referred by another hospital for treatment, and four of these underwent multidisciplinary treatment. Among the seven patients who underwent multidisciplinary treatment, three, two, and two were categorized in Pre-treatment Extent of Disease (PRETEXT) classification group I, II, and III, respectively. Neoadjuvant chemotherapy resulting in tumor reduction was performed in three cases. In all the cases, complete resection was achieved with pathologically safe margins. Perioperative complications included circulatory failure in one case and bile leakage in two cases. Adjuvant chemotherapy was administered in four cases. The postoperative observation period ranged from 3 months to 11 years, and all the patients are recurrence-free. CONCLUSION: Children with trisomy 18 complicated with hepatoblastoma whose cardiopulmonary conditions are stable may be good candidates for chemotherapy and surgery.

Low-level mosaic trisomy 7 at amniocentesis in a pregnancy associated with cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes, perinatal progressive decrease of the trisomy 7 cell line and a favorable fetal outcome.

OBJECTIVE: We present low-level mosaic trisomy at amniocentesis in a pregnancy associated with cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes, perinatal progressive decrease of the trisomy 7 cell line and a favorable fetal outcome. CASE REPORT: A 40-year-old, primigravid woman underwent amniocentesis at 16 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 46,XY in cultured amniocytes. Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed the result of arr (7) × 2-3, (X,Y) × 1, consistent with 24% mosaicism for trisomy 7. Polymorphic DNA marker analysis on the DNA extracted from the uncultured amniocytes and parental bloods excluded uniparental disomy (UPD) 7. Prenatal ultrasound findings were normal. She was referred for genetic counseling at 19 weeks of gestation. No repeat amniocentesis was suggested, and continuing the pregnancy was advised. At 22 weeks of gestation, the result of soluble fms-like tyrosine kinase-1 (sFlt-1)/placental growth factor (PlGF) = 6.1 (normal < 38). She did not have preeclampsia. At 39 weeks of gestation, a 3346-g male baby was delivered without any phenotypic abnormality. aCGH analysis on the DNA extracted from cord blood and placenta revealed the result of arr (1-22) × 2, (X,Y) × 1 with no genomic imbalance in all tissues. When follow-up at age three months, the baby was normal in development and phenotype. The peripheral blood had a karyotype of 46,XY, and interphase fluorescence in situ hybridization (FISH) analysis using the bacterial artificial chromosome (BAC) probes of chromosome 7 showed disomy 7 cells in all 102/102 cells. CONCLUSION: Low-level mosaic trisomy 7 at amniocentesis can be associated with cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes, perinatal progressive decrease of the trisomy 7 cell line and a favorable fetal outcome.

Sleep EEG signatures in mouse models of 15q11.2-13.1 duplication (Dup15q) syndrome.

BACKGROUND: Sleep disturbances are a prevalent and complex comorbidity in neurodevelopmental disorders (NDDs). Dup15q syndrome (duplications of 15q11.2-13.1) is a genetic disorder highly penetrant for NDDs such as autism and intellectual disability and it is frequently accompanied by significant disruptions in sleep patterns. The 15q critical region harbors genes crucial for brain development, notably UBE3A and a cluster of gamma-aminobutyric acid type A receptor (GABAAR) genes. We previously described an electrophysiological biomarker of the syndrome, marked by heightened beta oscillations (12-30 Hz) in individuals with Dup15q syndrome, akin to electroencephalogram (EEG) alterations induced by allosteric modulation of GABAARs. Those with Dup15q syndrome exhibited increased beta oscillations during the awake resting state and during sleep, and they showed profoundly abnormal NREM sleep. This study aims to assess the translational validity of these EEG signatures and to delve into their neurobiological underpinnings by quantifying sleep physiology in chromosome-engineered mice with maternal (matDp/ + mice) or paternal (patDp/ + mice) inheritance of the full 15q11.2-13.1-equivalent duplication, and mice with duplication of just the UBE3A gene (Ube3a overexpression mice; Ube3a OE mice) and comparing the sleep metrics with their respective wildtype (WT) littermate controls. METHODS: We collected 48-h EEG/EMG recordings from 35 (23 male, 12 female) 12-24-week-old matDp/ + , patDp/ + , Ube3a OE mice, and their WT littermate controls. We quantified baseline sleep, sleep fragmentation, spectral power dynamics during sleep states, and recovery following sleep deprivation. Within each group, distinctions between Dup15q mutant mice and WT littermate controls were evaluated using analysis of variance (ANOVA) and student's t-test. The impact of genotype and time was discerned through repeated measures ANOVA, and significance was established at p < 0.05. RESULTS: Our study revealed that across brain states, matDp/ + mice mirrored the elevated beta oscillation phenotype observed in clinical EEGs from individuals with Dup15q syndrome. Time to sleep onset after light onset was significantly reduced in matDp/ + and Ube3a OE mice. However, NREM sleep between Dup15q mutant and WT littermate mice remained unaltered, suggesting a divergence from the clinical presentation in humans. Additionally, while increased beta oscillations persisted in matDp/ + mice after 6-h of sleep deprivation, recovery NREM sleep remained unaltered in all groups, thus suggesting that these mice exhibit resilience in the fundamental processes governing sleep-wake regulation. CONCLUSIONS: Quantification of mechanistic and translatable EEG biomarkers is essential for advancing our understanding of NDDs and their underlying pathophysiology. Our study of sleep physiology in the Dup15q mice underscores that the beta EEG biomarker has strong translational validity, thus opening the door for pre-clinical studies of putative drug targets, using the biomarker as a translational measure of drug-target engagement. The unaltered NREM sleep may be due to inherent differences in neurobiology between mice and humans. These nuanced distinctions highlight the complexity of sleep disruptions in Dup15q syndrome and emphasize the need for a comprehensive understanding that encompasses both shared and distinct features between murine models and clinical populations.

Extracranial metastatic oligodendroglioma with molecular progression, case presentation.

BACKGROUND: Extraneural metastasis of central nervous system tumors is generally rare and most often reported in glioblastomas and medulloblastomas, whereas oligodendrogliomas seem to have the lowest risk of extracranial metastasis. Given its infrequent occurrence, both the diagnosis and therapy of metastatic oligodendroglioma is often challenging. CASE PRESENTATION: This case study presents an oligodendroglioma, the isocitrate dehydrogenase 1 (IDH1) mutant, 1p/19q-codeleted tumor with bone marrow metastasis. The significance of this case lies in the comprehensive molecular analysis conducted for both the primary tumor and the metastasis. Chromosome 7 trisomy and chromosome 10 monosomy (+ 7/-10) were detected in the metastasis indicating molecular progression, which, to the best of our knowledge, has not been previously documented in metastatic oligodendroglioma. CONCLUSIONS: This case study serves additional information for better understanding of the metastatic capabilities of CNS tumors.

Cell-type-specific effects of autism-associated 15q duplication syndrome in the human brain.

Recurrent copy-number variation represents one of the most well-established genetic drivers in neurodevelopmental disorders, including autism spectrum disorder. Duplication of 15q11-q13 (dup15q) is a well-described neurodevelopmental syndrome that increases the risk of autism more than 40-fold. However, the effects of this duplication on gene expression and chromatin accessibility in specific cell types in the human brain remain unknown. To identify the cell-type-specific transcriptional and epigenetic effects of dup15q in the human frontal cortex, we conducted single-nucleus RNA sequencing and multi-omic sequencing on dup15q-affected individuals (n = 6) as well as individuals with non-dup15q autism (n = 7) and neurotypical control individuals (n = 7). Cell-type-specific differential expression analysis identified significantly regulated genes, critical biological pathways, and differentially accessible genomic regions. Although there was overall increased gene expression across the duplicated genomic region, cellular identity represented an important factor mediating gene-expression changes. As compared to other cell types, neuronal subtypes showed greater upregulation of gene expression across a critical region within the duplication. Genes that fell within the duplicated region and had high baseline expression in control individuals showed only modest changes in dup15q, regardless of cell type. Of note, dup15q and autism had largely distinct signatures of chromatin accessibility but shared the majority of transcriptional regulatory motifs, suggesting convergent biological pathways. However, the transcriptional binding-factor motifs implicated in each condition implicated distinct biological mechanisms: neuronal JUN and FOS networks in autism vs. an inflammatory transcriptional network in dup15q microglia. This work provides a cell-type-specific analysis of how dup15q changes gene expression and chromatin accessibility in the human brain, and it finds evidence of marked cell-type-specific effects of this genetic driver. These findings have implications for guiding therapeutic development in dup15q syndrome, as well as understanding the functional effects of copy-number variants more broadly in neurodevelopmental disorders.

[Clinicopathological and molecular genetic features of confined placental mosaicism].

Objective: To investigate the clinicopathological and genetic features of confined placental mosaicism (CPM) and its effect on fetal intrauterine growth. Methods: Fourteen CPM cases of Haidian Maternal and Children Health Hospital were collected from May 2018 to March 2022. Clinicopathological examination on placental specimens and molecular genetic analysis were performed. Results: The age of the parturient women ranged from 27 to 34 years, with an average age of (30.0±3.54) years. The gestational weeks ranged from 35+1 to 41+2 weeks. There were 4 premature births and 10 term births, among which 6 were female and 8 were male fetuses. Nine cases (9/14) had adverse pregnancy outcomes, including 7 cases of fetal growth restriction. The weight of CPM placenta decreased, with 6 cases below the 10th percentile of weight standards and 5 cases between the 10th and 25th percentile. All 14 CPM placental specimens showed morphological changes of perfusion dysfunction to varying degrees, with mainly placental-maternal vascular malperfusion followed by placental-fetal vascular malperfusion. The mosaic chromosomes in different CPM cases varied, with 16-trisomy/monosomy mosaicism being the most common followed by 7-trisomy and 21-trisomy/monosomy mosaicism. The mosaic proportion was unequal in different parts of the same CPM placenta, with the mosaic proportion of umbilical cord, fetal membranes, fetal surface, maternal surface, and edge ranging from 1% to 70%. Conclusions: The mosaic chromosomes in different CPM cases vary, and the mosaic proportion is unequal in different parts of the same CPM placenta. The pathological morphology is mainly manifested as perfusion dysfunction, which can lead to adverse pregnancy outcomes such as fetal growth restriction and preterm birth.

Multicolour and lineage-specific interphase chromosome Flow-FISH: method development and clinical validation.

Flow cytometry can be applied in the detection of fluorescence in situ hybridisation (FISH) signals to efficiently analyse chromosomal aberrations. However, such interphase chromosome (IC) Flow-FISH protocols are currently limited to detecting a single colour. Furthermore, combining IC Flow-FISH with conventional multicolour flow cytometry is difficult because the DNA-denaturation step in FISH assay also disrupts cellular integrity and protein structures, precluding subsequent antigen-antibody binding and hindering concurrent labeling of surface antigens and FISH signals. We developed a working protocol for concurrent multicolour flow cytometry detection of nuclear IC FISH signals and cell surface markers. The protocol was validated by assaying sex chromosome content of blood cells, which was indicative of chimerism status in patients who had received sex-mismatched allogeneic haematopoietic stem cell transplants (allo-HSCT). The method was also adapted to detect trisomy 12 in chronic lymphocytic leukaemia (CLL) subjects. We first demonstrated the feasibility of this protocol in detecting multiple colours and concurrent nuclear and surface signals with high agreement. In clinical validation experiments, chimerism status was identified in clinical samples (n=56) using the optimised IC Flow-FISH method; the results tightly corresponded to those of conventional slide-based FISH (R2=0.9649 for XX cells and 0.9786 for XY cells). In samples from patients who received sex-mismatched allo-HSCT, individual chimeric statuses in different lineages could be clearly distinguished with high flexibility in gating strategies. Furthermore, in CLL samples with trisomy 12, this method could demonstrate that enriched trisomy 12 FISH signal was present in B cells rather than in T cells. Finally, by performing combined labelling of chromosome 12, X chromosome, and surface markers, we could detect rare residual recipient CLL cells with trisomy 12 after allo-HSCT. This adaptable protocol for multicolour and lineage-specific IC Flow-FISH advances the technique to allow for its potential application in various clinical contexts where conventional FISH assays are currently being utilised.