OBJECTIVE: To explore the molecular cytogenetic characteristics of three fetuses with psu idic(Y)(q11.22) using a combination of multiple methods. METHODS: A total of 11 000 pregnant women who underwent prenatal diagnosis at the Prenatal Diagnosis Center of Taizhou City from January 2019 to October 2024 were selected as the study subjects. Chromosome karyotype analysis (G-banding) and copy number variation analysis based on next-generation sequencing (NGS) were performed on the amniotic fluid/cord blood samples of the 11 000 fetuses. For cases suspected of Y chromosome abnormalities, C-banding and/or fluorescence in situ hybridization (FISH) and AZF microdeletion testing were additionally conducted. This study has been reviewed and approved by the Medical Ethics Committee of Taizhou Hospital, Zhejiang Province (Ethics No. KL20240860). RESULTS: Among the 11,000 prenatal samples undergoing concurrent karyotype and copy number variation analysis, two fetuses with 45,X/46,X,psu idic(Y)(q11.22) mosaicism and one fetus with 46,X,psu idic(Y)(q11.22) were detected. FISH detection indicated that approximately 66.7% of the cells in fetus 2 exhibited a dicentric Y chromosome, and the metaphase karyotype supported the presence of a pseudodicentric chromosome. AZF testing revealed complete deletion of the AZFb+AZFc regions in fetus 2 and fetus 3. CONCLUSION Conventional G-banding karyotype analysis for psu idic(Y)(q11.22) is prone to misdiagnosis or missed diagnosis. The combined application of chromosome karyotype analysis (G+C banding), copy number variation analysis, and FISH detection in clinical practice can accurately diagnose fetuses with psu idic(Y).
Humans ; Female ; Pregnancy ; Prenatal Diagnosis/methods* ; DNA Copy Number Variations/genetics* ; Adult ; Chromosomes, Human, Y/genetics* ; Karyotyping ; In Situ Hybridization, Fluorescence ; Cytogenetic Analysis/methods* ; Fetus ; High-Throughput Nucleotide Sequencing ; Male

OBJECTIVE: To assess the value of chromosomal microarray analysis (CMA) for the detection of low-level mosaicisms in amniotic fluid samples, and to retrospectively analyze the rare cases of mosaicisms. METHODS: Chromosomal karyotype of the fetus was determined by G-banding analysis of cultured amniotic fluid cells. CMA was used to detect copy number variation of fetal chromosomes, and fluorescence in situ hybridization (FISH) was used to determine the proportion of fetal chromosomal mosaicisms in uncultured amniotic fluid cells. RESULTS: Among 825 prenatal samples, 4 cases of true fetal mosaicisms were detected, which yielded an incidence of 0.48%. Two cases were sex chromosomal mosaicisms, and two were autosomal mosaicisms, which involved chromosomes 8 and 9, respectively. All cases were verified by G-banding analysis of cultured amniotic fluid cells, CMA, and/or FISH. CONCLUSION CMA has a great value for detecting low-level mosaicisms in amniotic fluid samples, though the positive results need to be verified by other techniques and should be interpreted with caution. The review of rare cases can provide a basis for prenatal genetic counseling.
Humans ; Female ; Amniotic Fluid/metabolism* ; Pregnancy ; Mosaicism/embryology* ; Prenatal Diagnosis/methods* ; Adult ; In Situ Hybridization, Fluorescence ; Microarray Analysis/methods* ; Karyotyping ; Retrospective Studies ; Male

OBJECTIVE: To explore the reasons for false negative results by Optical genome mapping (OGM) analysis of three cases and propose strategies for handling them. METHODS: Three patients presented at the Affiliated Hospital of Nantong University between July 2022 and July 2024 were selected as study subjects. The patients included a 37-year-old female with two miscarriages, a 1.5-year-old boy with delayed motor development, and a 35-year-old male whose son had intellectual disability. The patients had undergone comprehensive evaluation with chromosomal karyotyping analysis, single nucleotide polymorphism microarray (SNP array) assay, fluorescence in situ hybridization (FISH), and methylation-specific multiple ligation-dependent probe amplification (MS-MLPA). A retrospective analysis was also carried out on the results of OGM testing. This study was approved by the Medical Ethics Committee of the Hospital (Ethics No.: 2020-K004). RESULTS: The chromosomal karyotype of patient 1 was 46,XX,4qs, and no abnormality was found by SNP array, FISH, and OGM testing. Patient 2 had a normal chromosomal karyotype, and SNP array analysis did not reveal any copy number abnormalities of chromosomal fragments but the presence of a homozygous region of approximately 79.58 Mb at 15q11.2-q26.3 (chr15: 22817871_102397317). MS-MLPA detection indicated that the copy number of the 15q11.2-q13 region was 2, and the degree of methylation was relatively high (average ratio = 1.0). OGM detection confirmed the presence of approximately 67.97 Mb of homozygosity in the chr15:33814680_101787650 [hg38] region of 15q14-q26.3. Patient 3 had a chromosomal karyotype of 46,XY,t(9;14)(q13;q11.2). No abnormality was found by OGM testing for patients 1 and 3. CONCLUSION As a novel cytogenetic technique, OGM can achieve high-resolution and high-precision analysis for numerical and structural genomic abnormalities. Nevertheless, it also has certain limitations, as its false negative results are related to factors such as the type of genomic variation, the chromosomal regions involved in the variation, the type of disease, and the version of human reference genome. Currently, it cannot be used as an independent method for the diagnosis of genetic diseases.
Humans ; Male ; Female ; Adult ; Polymorphism, Single Nucleotide/genetics* ; Karyotyping ; Chromosome Mapping/methods* ; Infant ; False Negative Reactions ; In Situ Hybridization, Fluorescence

OBJECTIVE: To explore the coincidence rate of G-banding karyotype analysis and fluorescence in situ hybridization (FISH) for the diagnosis of children with sex chromosome mosaicisms. METHODS: A retrospective analysis was carried out for 157 children with suspected sex chromosome abnormalities who had presented at Shenzhen Children's Hospital from April 2021 to May 2022. Interphase sex chromosome FISH and G-banding karyotyping results were collected. The coincidence rate of the two methods in children with sex chromosome mosaicisms was compared. RESULTS: The detection rates of G-banding karyotype analysis and FISH were 26.1% (41/157) and 22.9% (36/157) , respectively (P > 0.05). The results of G-banding karyotype analysis showed that 141 cases (89.8%) were in the sex chromosome homogeneity group, of which only 5 cases (3.5%) were inconsistent with the results of FISH. There were 16 cases (10.2%) in the sex chromosome mosaicism group, of which 11 cases (68.8%) were inconsistent with the results of FISH. There was a statistical difference between the two groups in the coincidence rate of the results of the two methods (P < 0.05). CONCLUSION No significant difference was found between G-banding karyotype analysis and FISH in the detection rate of chromosome abnormalities. The coincidence rate in the mosaicism group was lower than that in the homogeneity group, and the difference was statistically significant. The two methods should be combined for clinical diagnosis.
Humans ; Mosaicism ; In Situ Hybridization, Fluorescence/methods* ; Retrospective Studies ; Karyotyping ; Chromosome Aberrations ; Sex Chromosome Aberrations ; Karyotype ; Chromosome Banding ; Sex Chromosomes

OBJECTIVE: To explore the genetic basis for a rare case of acute B-lymphocytic leukemia (B-ALL) with double Philadelphia chromosomes (Ph) and double derivative chromosome 9s [der(9)]. METHODS: A patient with double Ph and double der(9) B-ALL who presented at Shanghai Zhaxin Intergrated Traditional Chinese and Western Medicine Hospital in June 2020 was selected as the subject. Bone marrow morphology, flow cytometry, G-banding karyotyping, fluorescence in situ hybridization (FISH), genetic testing and chromosomal microarray analysis (CMA) were used to analyze bone marrow samples from the patient at various stages. RESULTS: At initial diagnosis, the patient's bone marrow morphology and flow immunotyping have both supported the diagnosis of B-ALL. G-banded karyotyping of the patient indicated double Ph, in addition with hyperdiploid chromosomes involving translocations between chromosomes 9 and 22. BCR-ABL1 fusion gene was positive. Genetic testing at the time of recurrence revealed presence of a heterozyous c.944C>T variant in the kinase region of the ABL1 gene. FISH showed a signal for ABL1-BCR fusion on both chromosome 9s. CMA showed that the mosaicism homozygosity ratio of chromosome 9 was about 40%, and the mosaicism duplication ratio of chromosome 22 was about 43%. CONCLUSION Since both der(9) homologs were seen in 40% of cells, the possible mechanism for the double der(9) in this patient may be similar to that of double Ph, which might have resulted from non-disjunction during mitosis in the Ph chromosome-positive cell clone.
Humans ; Philadelphia Chromosome ; In Situ Hybridization, Fluorescence/methods* ; China ; Chromosome Aberrations ; Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics* ; Translocation, Genetic ; Fusion Proteins, bcr-abl/genetics* ; Chromosomes, Human, Pair 9/genetics*

OBJECTIVE: To assess the value of chromosomal microarray analysis (CMA) and fluorescence in situ hybridization (FISH) for the prenatal diagnosis of chromosomal mosaicisms. METHODS: A total of 775 pregnant women who had visited the Prenatal Diagnosis Center of Yancheng Maternal and Child Health Care Hospital from January 2018 to December 2020 were selected as study subjects. Chromosome karyotyping analysis and CMA were carried out for all women, and FISH was used to validate the suspected mosaicism cases. RESULTS: Among the 775 amniotic fluid samples, karyotyping has identified 13 mosaicism cases, which yielded a detection rate of 1.55%. Respectively, there were 4, 3, 4 and 2 cases for sex chromosome number mosaicisms, abnormal sex chromosome structure mosaicisms, abnormal autosomal number mosaicisms and abnormal autosomal structure mosaicisms. CMA has only detected only 6 of the 13 cases. Among 3 cases verified by FISH, 2 cases were consistent with the karyotyping and CMA results, and clearly showed low proportion mosaicism, and 1 case was consistent with the result of karyotyping but with a normal result by CMA. Eight pregnant women had chosen to terminate the pregnancy (5 with sex chromosome mosaicisms and 3 with autosomal mosaicisms). CONCLUSION For fetuses suspected for chromosomal mosaicisms, CMA, FISH and G-banding karyotyping should be combined to determine the type and proportion of mosaicisms more precisely in order to provide more information for genetic counseling.
Female ; Pregnancy ; Humans ; Mosaicism ; In Situ Hybridization, Fluorescence ; Chromosome Disorders/genetics* ; Prenatal Diagnosis/methods* ; Chromosome Aberrations ; Sex Chromosome Aberrations ; Microarray Analysis/methods* ; Chromosomes

OBJECTIVE: To carry out prenatal genetic testing for a fetus with de novo 46,X,der(X)t(X;Y)(q26;q11). METHODS: A pregnant woman who had visited the Birth Health Clinic of Lianyungang Maternal and Child Health Care Hospital on May 22, 2021 was selected as the study subject. Clinical data of the woman was collected. Peripheral blood samples of the woman and her husband and umbilical cord blood of the fetus were collected and subjected to conventional G-banded chromosomal karyotyping analysis. Fetal DNA was also extracted from amniotic fluid sample and subjected to chromosomal microarray analysis (CMA). RESULTS: For the pregnant women, ultrasonography at 25th gestational week had revealed permanent left superior vena cava and mild mitral and tricuspid regurgitation. G-banded karyotyping analysis showed that the pter-q11 segment of the fetal Y chromosome was connected to the Xq26 of the X chromosome, suggesting a Xq-Yq reciprocal translocation. No obvious chromosomal abnormality was found in the pregnant woman and her husband. The CMA results showed that there was approximately 21 Mb loss of heterozygosity at the end of the long arm of the fetal X chromosome [arr [hg19] Xq26.3q28(133912218_154941869)×1], and 42 Mb duplication at the end of the long arm of the Y chromosome [arr [hg19] Yq11.221qter(17405918_59032809)×1]. Combined with the search results of DGV, OMIM, DECIPHER, ClinGen and PubMed databases, and based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the deletion of arr[hg19] Xq26.3q28(133912218_154941869)×1 region was rated as pathogenic, and the duplication of arr[hg19] Yq11.221qter(17405918_59032809)×1 region was rated as variant of uncertain significance. CONCLUSION The Xq-Yq reciprocal translocation probably underlay the ultrasonographic anomalies in this fetus, and may lead to premature ovarian insufficiency and developmental delay after birth. Combined G-banded karyotyping analysis and CMA can determine the type and origin of fetal chromosomal structural abnormalities as well as distinguish balanced and unbalanced translocations, which has important reference value for the ongoing pregnancy.
Humans ; Child ; Pregnancy ; Female ; Vena Cava, Superior ; In Situ Hybridization, Fluorescence ; Chromosome Aberrations ; Karyotyping ; Translocation, Genetic ; Fetus ; Prenatal Diagnosis/methods*

OBJECTIVE: To investigate the value of using MDM2 amplification probe and DDIT3 dual-color, break-apart rearrangement probe fluorescence in situ hybridization (FISH) technique in the diagnosis of liposarcoma. METHODS: In the study, 62 cases of liposarcoma diagnosed in Peking University First Hospital from January 2015 to December 2019 were analysed for clinicopathological information. Of these 62 cases of liposarcoma, all were analysed for MDM2 amplification and 48 cases were analysed for DDIT3 rearrangement using a FISH technique. Our study aimed to evaluate the status of MDM2 and DDIT3 by FISH in liposarcoma and correlate it with diagnosis of different subtypes of liposarcoma. The subtypes of liposarcoma were classified according to the FISH results, combined with the relevant clinicopathological features. RESULTS: The patients aged 31-89 years (mean: 59 years) with a 1.75:1 male to female ratio. Histologically, there were 20 cases of atypical lipomatous tumour/well-differentiated liposarcoma (ALT/WDLPS), 26 cases of dedifferentiated liposarcoma (DDLPS), 13 myxoid liposarcoma (MLPS) and 3 pleomorphic liposarcoma (PLPS). Tumors with DDLPS (23/26) and WDLPS (8/20) were localized retroperitoneally, while both tumours of MLPS and PLPS were localized extra-retroperitoneally, and the difference of sites among the four subtypes of liposarcoma was statistically significant (P < 0.05). Histologically, varied mucoid matrix could be observed in the four subtypes of liposarcoma, and the difference was statistically significant (P < 0.05). MDM2 gene amplification was demonstrated in all cases of ALT/WDLPS and DDLPS (100%, 20/20 and 26/26 respectively); DDIT3 gene rearrangement was noted only in MLPS (100%, 13/13); most cases of DDLPS (96.2%, 25/26) and ALT/WDLPS (83.3%, 5/6, 6 cases selected for detection) demonstrated the picture of amplification of the DDIT3 telomeric tag. According to the instructions of DDIT3 break-apart rearrangement probe, the 5' telomere probe and 3' centromere probe spanned but did not cover the DDIT3 gene itself, on the contrary, the 5' telomere probe covered the CDK4 gene, while the DDIT3 and CDK4 gene were located adjacent to each other on chromosome, therefore, when the amplification signal appeared on the telomeric tag of the DDIT3 rearrangement probe, it indeed indicated the CDK4 gene amplification rather than the DDIT3 gene rearrangement. Then the 10 cases with DDIT3 telomeric tag amplification were selected for CDK4 and DDIT3 gene amplification probe FISH tests, and all the cases showed CDK4 gene amplification (100%, 10/10) and two of the 10 cases demonstrated co-amplification of CDK4 and DDIT3 (20%, 2/10); DDIT3 polysomy detected by DDIT3 gene rearrangement probe was found in 1 case of DDLPS and 2 cases of PLPS (66.7%, 2/3) with morphology of high-grade malignant tumour and poor prognosis. CONCLUSION Our results indicate that a diagnosis of different subtype liposarcoma could be confirmed based on the application of MDM2 and DDIT3 FISH, combined with clinicopathological findings. It is also noteworthy that atypical signals should be correctly interpreted to guide correct treatment of liposarcomas.
Male ; Female ; Humans ; In Situ Hybridization, Fluorescence/methods* ; Cyclin-Dependent Kinase 4/metabolism* ; Liposarcoma/pathology* ; Lipoma/pathology* ; Gene Amplification ; Transcription Factor CHOP/genetics* ; Proto-Oncogene Proteins c-mdm2/metabolism*

OBJECTIVE: To validate a fetus with high risk for trisomy 13 suggested by non-invasive prenatal testing (NIPT). METHODS: The fetus was selected as the study subject after the NIPT detection at Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences on February 18, 2019. Clinical data of the pregnant woman was collected. Fluorescence in situ hybridization (FISH), chromosomal karyotyping analysis and chromosomal microarray analysis (CMA) were carried out on amniotic fluid and umbilical cord blood and the couple's peripheral blood samples. Copy number variation sequencing (CNV-seq) was also performed on the placental and amniotic fluid samples following induced labor. RESULTS: The pregnant woman, a 38-year-old G4P1 gravida, was found to have abnormal fetal development by prenatal ultrasonography. NIPT test suggested that the fetus has a high risk for trisomy 13. Chromosomal karyotyping analysis of fetal amniotic fluid and umbilical cord blood were 46,XN,add(13)(p10). The result of CMA was arr[hg19]1q41q44(223937972_249224684)×3, with the size of the repeat fragment being approximately 25.29 Mb, the fetal karyotype was thereby revised as 46,XN,der(13)t(1;13)(q41;p10). Chromosomal karyotyping analysis and CMA of the parents' peripheral blood samples showed no obvious abnormality. The CNV-seq analysis of induced placenta revealed mosaicisms of normal karyotype and trisomy 13. The CNV-seq test of induced amniotic fluid confirmed a duplication of chr1:22446001_249220000 region spanning approximately 24.75 Mb, which was in keeping with the CMA results of amniotic fluid and umbilical cord blood samples. CONCLUSION NIPT may yield false positive result due to placenta mosaicism. Invasive prenatal diagnosis should be recommended to women with a high risk by NIPT test. And analysis of placenta can explain the inconsistency between the results of NIPT and invasive prenatal diagnosis.
Humans ; Female ; Pregnancy ; Trisomy 13 Syndrome/genetics* ; DNA Copy Number Variations ; Placenta ; Chromosomes, Human, Pair 1 ; In Situ Hybridization, Fluorescence ; Prenatal Diagnosis/methods* ; Fetus ; Amniotic Fluid ; Chromosome Aberrations ; Trisomy/genetics*

OBJECTIVE: To carry out cyto- and molecular genetic analysis for a fetus with a ring chromosome identified through non-invasive prenatal testing (NIPT). METHODS: A pregnant woman presented at the Shengjing Hospital Affiliated to China Medical University on May 11, 2021 was selected as the study subject. Maternal peripheral blood sample was screened by NIPT, and G-banded chromosomal karyotyping was carried out on amniotic fluid and peripheral blood samples from the couple. The fetus and the pregnant woman were also subjected to genomic copy number variation sequencing (CNV-seq), chromosomal microarray analysis (CMA), and fluorescence in situ hybridization (FISH) assay. RESULTS: NIPT result suggested that the fetus had monomeric mosaicism or fragment deletion on chromosome 13. G banded chromosomal analysis showed that both the fetus and its mother had a karyotype of 47,XX,der(13)(pter→p11::q22→q10),+r(13)(::p10::q22→qter::), whilst her husband had a normal karyotype. FISH has verified the above results. No abnormality was detected with CNV-seq and CMA in both the fetus and the pregnant woman. CONCLUSION The ring chromosome 13 in the fetus has derived from its mother without any deletion, duplication and mosaicism. Both the fetus and the pregnant woman were phenotypically normal.
Humans ; Pregnancy ; Female ; Ring Chromosomes ; Chromosomes, Human, Pair 13/genetics* ; In Situ Hybridization, Fluorescence ; DNA Copy Number Variations ; Prenatal Diagnosis/methods* ; Amniotic Fluid