Conventional G-banding Karyotyping Research Articles

Genetic analysis of a fetus with Pitt-Hopkins syndrome due to a 18q21.2q21.31 microdeletion

To carry out invasive prenatal diagnosis for a fetus with ultrasound-indicated agenesis of corpus callosum and explore its genetic etiology. A pregnant woman presented at the Affiliated Hospital of Putian College on December 16, 2022 was selected as the study subject. Amniotic fluid and peripheral blood samples from the fetus and the couple were collected. Conventional G-banded chromosomal karyotyping was carried out, and whole-genome copy number variation analysis was performed using single nucleotide polymorphism microarray (SNP-array). The karyotypes of the fetus and the couple were normal by the G-banding analysis. SNP-array analysis of the amniotic fluid sample revealed a 4.5 Mb microdeletion in the 18q21.2q21.31 region of the fetus. SNP-array analysis of peripheral blood samples from the couple did not find any abnormality. Through G-banded chromosomal karyotyping and SNP-array analysis, a fetus with 18q21.2q21.31 microdeletion was identified, which has conformed to the diagnosis of Pitt-Hopkins syndrome. Above finding has provided a basis for genetic counseling for the couple.

Analysis of a twin pregnancy with false negative result for 22q11.2 deletion syndrome by expanded non-invasive prenatal testing

To explore the cause for a twin pregnancy with false negative result for 22q11.2 deletion syndrome by expanded non-invasive prenatal testing (NIPT-plus). A pregnant woman with twin pregnancy through in-vitro fertilization and negative result of NIPT-plus was selected as the study subject. Amniocentesis was conducted after ultrasonic finding of fetal abnormalities. In addition to conventional G-banded karyotyping, copy number variation sequencing (CNV-Seq) was used to detect chromosomal microdeletion and microduplication. Clinical data of the woman were analyzed to explore the reasons underlying the false negative result. NIPT-plus has yielded a negative result with 11.77 Mb unique reads and 3.05% fetal fraction. Both fetuses had a normal karyotype (46,XY and 46,XX). CNV-seq indicated that one of the fetuses was normal, whilst the other was diagnosed with a 2.58 Mb deletion in the 22q11.2 region. The false negative result may be attributed to the combined influence of low fetal fraction, high BMI, twin pregnancy through IVF and a relatively small deletion fragment. Ultrasonography exam following a low-risk result of NIPT-plus should not be neglected.

Prenatal diagnosis of a case with Schuurs-Hoeijmakers syndrome

To explore the genetic basis for a fetus with multiple malformations. Clinical data of the fetus was collected, Amniotic fluid sample of the fetus was subjected to conventional G-banded karyotyping, low-depth whole genome copy number variants detection and whole exome sequencing (WES). Candidate variant was verified by Sanger sequencing of the fetus and its parents. Prenatal ultrasound scan at 21+5 gestational weeks had revealed increased nuchal thickness (9.0 mm), enhanced echos of bilateral renal parenchyma, seroperitoneum, left pleural effusion and right displacement of the heart. The mother had a previous history of terminated pregnancy for multiple fetal anomalies. No abnormality was found by conventional karyotyping and CNV analysis, though WES revealed that the fetus has harbored a de novo heterozygous c.607C>T (p.Arg203Trp) variant of the ACS1 gene (NM_018026.3), and the result was validated by Sanger sequencing. Through WES and prenatal ultrasonography, the fetus was diagnosed with Schuurs-Hoeijmakers syndrome due to the heterozygous c.607C>T (p.Arg203Trp) variant of the PACS1 gene (NM_018026.3). For fetuses with multiple malformations, WES can help to reveal the genetic etiology when CNV result is negative.

Clinical features and genetic analysis of two fetuses with ring chromosome 21 mosaicism

To investigate the perinatal clinical phenotype and genetic characteristics of two fetuses with ring chromosome 21 mosaicisms. Two fetuses who were diagnosed at the Xiamen Maternal and Child Health Care Hospital in November 2021 were selected as the study subjects. Clinical data of the two fetuses were collected. Conventional G-banded karyotyping and chromosomal microarray analysis (CMA) were carried out for the fetuses and their parents. Prenatal ultrasonography of fetus 1 has revealed absence of nasal bone, ventricular septal defect, persistent left superior vena cava, and mild tricuspid regurgitation. Chromosomal karyotyping was 46,X?,dic r(21;21)(p12q22;q22p12)[41]/45,X?,-21[9]. CMA has revealed a 30.00 Mb quadruplication at 21q11.2q22.3 and a 3.00 Mb deletion at 21q22.3. For fetus 2, ultrasonography has revealed pointed echo of the nasal bone. The fetus was found to have a karyotype of 46,X?,r(21)(p12q22)[83]/45,X?,-21[14]/46,X?,dic r(21;21)(p12q22;q22p12)[3]. CMA has revealed a 5.10 Mb quadruplication at 21q22.12q22.3 and a 2.30 Mb deletion at 21q22.3. The perinatal phenotype of the two fetuses with ring chromosome 21 mosaicisms is related to the duplication of chromosomal segments near the breakpoints of the chromosomal deletions. The combined chromosomal karyotyping and CMA has enabled prenatal diagnosis and genetic counseling for these families.

Optical genome mapping for cytogenomic analysis of hematological neoplasms.

e19016 Background: Optical genome mapping (OGM) provides a genome-wide analysis for structural variants and copy number changes in one-assay. Compared with conventional G-banded karyotyping (GBK), OGM provides significantly higher resolution and does not require metaphase cells. In this study, we assessed the added value of OGM for cytogenomic analysis of hematological neoplasms. Methods: OGM was performed on blood or bone marrow using Saphyr from Bionano Genomics on 63 patients diagnosed with various types of hematological malignancy (see Table). Variant calling was made by the Rare Variant Analysis pipeline on Bionano Access after applying recommended filters. Each patient had karyotype and/or fluorescence in situ hybridization (FISH) results available for comparison and confirmation. Only Tier 1 (pathogenic) and Tier 2 (likely pathologic) abnormalities were included for comparison purposes in this study. Results: The results were completely concordant between GBK/FISH and OGM in 30 (47.6%) patients, including 10 patients who showed no cytogenetic abnormality (normal). Fully discordant results were found in 8 (12.7%) patients: 2 had an abnormal karyotype but normal OGM, the discrepancy was mainly due to the clonal size (<20%) below the limitation of detection of OGM; 6 had a normal karyotype but cytogenetic abnormalities were detected by OGM, the discrepancy was mainly due to failure of tumor cells growth (n=5) or subtle cytogenetic abnormality undetectable by GBK (n=1). Partially concordant results between karyotype/FISH and OGM were observed in 25 (40%) patients, some abnormalities were detected by both, some were detected by GBK alone (n=4) or by OGM alone (n=25), the latter group included 10 cases with chromothripsis which only be detected by OGM. Overall, OGM provided clinically significant information in 14 (22%) patients regarding diagnosis, risk stratification, and/or identifying therapeutic targets. The added value was more common in lymphoid neoplasms (9 of 27 patients, 33%). Conclusions: OGM provides additional clinically relevant cytogenetic information in the workup of hematological neoplasms. This added value is more apparent in lymphoid neoplasms. These improvements are largely contributable to the higher resolution provided by OGM and analysis independent of metaphase cells. A major limitation of OGM usage is the need for a clonal size of at least 20%. [Table: see text]

Genetic analysis of a fetus with de novo 46,X,der(X)t(X;Y)(q26;q11)

To carry out prenatal genetic testing for a fetus with de novo 46,X,der(X)t(X;Y)(q26;q11). 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). 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. 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.

Assessment of Combined Karyotype Analysis and Chromosome Microarray Analysis in Prenatal Diagnosis: A Cohort Study of 3710 Pregnancies.

The current study aimed to compare the characteristics of chromosome abnormalities detected by conventional G-banding karyotyping, chromosome microarray analysis (CMA), or fluorescence in situ hybridization (FISH)/CNVplex analysis and further explore the application value of combined karyotype analysis and CMA in prenatal diagnosis with a larger sample size. From March 2019 to March 2021, 3710 amniocentesis samples were retrospectively collected from women who accepted prenatal diagnosis at 16 to 22 + 6 weeks of pregnancy. The pregnant women underwent karyotype analysis and CMA. In the case of fetal chromosomal mosaicism, FISH or CNVplex analysis was utilized for validation. In total, 3710 G-banding karyotype results and CMA results from invasive prenatal diagnosis were collected. Of these, 201 (5.41%) fetuses with an abnormal karyotype were observed. The CMA analysis showed that the abnormality rate was 9.14% (340/3710). The detection rate of CMA combined with karyotype analysis was 0.35% higher than that of CMA alone and 4.08% higher than that of karyotyping alone. Additionally, 12 cases had abnormal karyotype analysis, despite normal CMA results. To further detect the chromosome mosaicism, we used FISH analysis to correct the karyotype results of case 1. Correspondingly, a total of 157 cases showed abnormal CMA results but normal karyotype analysis. We also found chromosomal mosaicism in 4 cases using CMA. Moreover, CNVplex and CMA demonstrated that representative case 15 was mosaicism for trisomy 2. Conventional G-banding karyotyping and CMA have their own advantages and limitations. A combination of karyotype analysis and CMA can increase the detection rate of chromosome abnormalities and make up for the limitation of signal detection.

Chromosomal copy number analysis of products of conception by conventional karyotyping and next-generation sequencing.

PurposeChromosomal abnormalities are a major cause of spontaneous abortion, and conventional G‐banded karyotyping (G‐banding) is mainly utilized for chromosomal analysis. Recently, next‐generation sequencing (NGS) has been introduced for chromosomal analysis. Here, we aimed to investigate the applicability and utility of NGS‐based chromosomal analysis of products of conception (POC) on chorionic villus samples from spontaneous abortion.MethodsThe results of chromosomal analysis of 7 chorionic villus samples from spontaneous abortion were compared between conventional G‐banding and NGS‐based chromosomal copy number analysis. Age dependency and frequency of each chromosomal aneuploidy were evaluated for 279 cases analyzed by NGS.ResultsExcluding two cases (culture failure and maternal cell contamination), the results were consistent between G‐banding and NGS. For cases analyzed by NGS, the rate of chromosomal abnormality increased in a maternal age‐dependent manner. The frequency of each chromosomal aneuploidy detected by NGS was almost the same as that previously reported. Finally, NGS analysis was possible for difficult cases by G‐banding analysis, such as culture failure, maternal cell contamination, long‐term storage cases, and low cell number.ConclusionsChromosome analysis using NGS not only obtains comparable results to conventional G‐banding, but also can analyze POC more accurately and efficiently.

Genetic analysis of a child with atypical Williams-Beuren syndrome presenting as supravalvular aortic stenosis

To explore the genetic basis for a child with supravalvular aortic stenosis. The child and his parents were subjected to conventional G-banding karyotyping, array comparative genomic hybridization (aCGH) and multiplex ligation-dependent probe amplification (MLPA) analysis. No karyotypic abnormality was detected in the child and his parents. aCGH has identified a de novo 278 kb deletion encompassing the ELN gene in 7q11.23, which overlapped with the critical region of Williams-Beuren syndrome (WBS). MLPA has confirmed above findings. The proband was diagnosed with atypical WBS. Deletion of the ELN gene may predispose to supravalvular aortic stenosis in the proband.

Clinical and genetic study of a child with delayed language development carrying ring 22 and a 22q13 microdeletion

To explore the genetic basis for a child featuring delayed language development. The patient was subjected to conventional G-banding chromosomal karyotyping and single nucleotide polymorphism microarray (SNP array) analysis. The karyotype of the child was 46, XY, r(22)(p11.2q13). SNP array analysis has identified a hemizygous 1.67 Mb deletion at 22q13 (arr [Hg19]22q13.33 (49 531 302-51 197 766)×1). The child has carried a ring 22 in addition with a 22q13 microdeletion. The results may provide clues for her condition and genetic counseling for the family.

Genome-wide cell-free DNA based non-invasive prenatal testing identifies trisomy 14 mosaicism in association with uniparental disomy

Cell free DNA (cfDNA) based non-invasive prenatal testing (NIPT) has revolutionised prenatal care. CfDNA NIPT assays are often NGS based, but also include microarray and single nucleotide polymorphism (SNP) based methods. The NGS based methods can be targeted capturing chromosomes 21, 18, 13, X and Y only, or genome wide. NGS based genome wide NIPT was utilised to analyse chromosomal aneuploidy for a 40-year-old woman who presented to Victorian Clinical Genetics Services for prenatal screening due to advanced maternal age. NIPT results identified a female fetus with an increased risk for trisomy 14. Amniocentesis was recommended following normal fetal ultrasound. SNP molecular karyotype analysis confirmed a genotyping profile consistent with mosaic trisomy 14. Genotype evidence for a cell line with uniparental disomy (UPD) 14 was also observed, and a maternal origin was subsequently determined (UPD14mat; Temple syndrome). A conventional G-banding karyotype on cultured amniotic fluid cells also demonstrated true fetal mosaicism for trisomy 14. The combination of UPD(14)mat and mosaic trisomy 14 is rare with approximately 8 live-born cases reported. This case study demonstrates the additional clinical utility of using an NGS based genome wide NIPT assay and represents the first report of UDP(14) ascertained using NIPT.

Genetic analysis of an adult with mosaicism of uniparental disomy 11p

To analyze the clinical phenotype and genomic abnormality of an adult featuring congenital heart defect and multiple developmental disorders. The patient was subjected to conventional G-banding chromosomal karyotyping and single nucleotide polymorphism microarray (SNP-array) analysis. The patient showed a normal karyotype, while SNP-array revealed a 42.7 Mb mosaic uniparental disomy (UPD) in the 11p15.5p12 region ([hg19] chr11: 491 333-43 189 376). The mosaicism of UPD of 11p15.5p12 region probably underlies the congenital heart defect and developmental disorders in the patient.

Prenatal diagnosis of monochorionic-diamniotic twins discordant for 45,X/46,XX mosaicism

To explore the prenatal screening and diagnosis for a pair of monochorionic-diamniotic (MCDA) twins discordant for 45,X/46,XX mosaicism. Amniotic fluid samples were taken from both twins for whom non-invasive prenatal testing has signaled a high risk for sex chromosomal abnormality. Uncultured amniotic fluid was analyzed by fluorescence in situ hybridization (FISH) and single nucleotide polymorphism array (SNP-array). Conventional G-banded karyotyping analysis was performed on the cultured amniotic fluid. Metaphase chromosome analysis showed that one of the twins had a mos 45,X[11]/46,XX[26] karyotype, while the other had a normal karyotype. FISH and SNP-array applied on uncultured amniotic fluid revealed about 30% mosaicism in one of the twins. The twins were confirmed to be monozygotic by SNP-array analysis. To avoid confusion arising from discordant karyotypes in MCDA twins with abnormal non-invasive prenatal testing (NIPT) results, dual amniocentesis should be carried out to obtain amniotic fluid samples for chromosomal as well as molecular analysis. To determine the ratio of 45,X and 46,XX cells in Turner syndrome can provide valuable information for prenatal genetic counseling.

Chromosomal Microarray Testing For Children With Unexplained Neurodevelopmental Disorders

(Abstracted from JAMA 2017;317(24):2545–2546) Chromosomal microarray analysis (CMA) has emerged as a robust means to detect chromosomal abnormalities including unbalanced chromosomal rearrangements, as well as smaller chromosomal abnormalities than those detectable by karyotype. Chromosomal microarray analysis has replaced conventional G-banded karyotyping due to its greater sensitivity and resolution; G-banding effectively identifies imbalances of DNA greater than 5 to 10 megabases (millions of base pairs), whereas CMA can detect genome-wide imbalances of more than 400 kilobases (thousands of base pairs).

P16.01: The value of prenatal chromosomal microarray analysis in fetuses with structural ultrasound abnormalities and a normal karyotype in China

The aim of this study was to evaluate the contribution of chromosomal microarray analysis (CMA) in the prenatal diagnosis of fetuses with structural anomalies but normal chromosomal karyotype. Fetuses with structural anomalies underwent chromosome conventional G-banding karyotyping. Fetuses with normal karyotype were performed on CMA including the array-based comparative genomic hybridisation (aCGH) and array-single-nucleotide polymorphism (SNP). Out of the 402 pregnancies with structural ultrasound abnormalities, karyotyping revealed a chromosomal abnormality in 33 (8.2%). Among fetuses with structural ultrasound abnormalities and normal karyotype(n=369) that underwent CMA, the detection rate of copy number variants (CNV) was 22.2% (82/369), including pathogenic CNV in 11.4% (42/369) and variants of uncertain clinical significance (VOUS) in 10.8% (40/369). In the groups of cardiac, central nervous, musculoskeletal, facial and urogenital malformations, the rate of the pathogenic CNV were 16.6% (38/229), 21.9% (14/64), 15.5% (15/97), 13.5% (7/52) and 18.8% (6/32) respectively. Ultrasound anomaly restricted to one anatomical system (n=238) had a 10.5% (n=25) chance of carrying a pathogenic CNV, while this chance increased to 13.0% (n=17) for multiple ultrasound anomalies (n=131). Supporting information can be found in the online version of this abstract Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Idiopathic congenital talipes equinovarus; not always an isolated anomaly. A review of long-term outcomes

Objective: To describe the long-term outcomes of children at school age who were thought to have isolated idiopathic congenital talipes equino varus (ICTEV) at birth.Method: A retrospective review of all children attending a regional talipes clinic who had achieved school age.Results: One hundred sixty-three children were followed up. ICTEV was more common in Maori and other Polynesian children and in males. Additional abnormalities were apparent in 30.1% overall, but higher in New Zealand Europeans (43%) than Maori (21%) or other Polynesians (22%). Of the abnormalities, 41% were associated with the central nervous system or with neurodevelopmental delay. Conventional G-band karyotyping, where performed, was not informative.Conclusions: The rate of additional abnormalities was higher than previous reports. This has implications for prenatal counseling and postnatal follow-up as a prenatal diagnosis of ICTEV may subsequently be found to have longer term implications in addition to orthopedic treatments of the clubfeet.

First trimester pregnancy loss: Clinical implications of genetic testing.

Around 10-15% of pregnancies result in a spontaneous first trimester miscarriage, which is most frequently caused by chromosomal abnormalities, mainly aneuploidies. Genetic analysis of pregnancy loss includes conventional G-banding karyotyping and various molecular methods. Apart from variable methodological limitations, the effectiveness of genetic analysis depends on the type and quality of the tested sample. To improve the reliability of genetic testing, we present methods of appropriate collection and pre-laboratory preparation of chorionic villi from first trimester miscarriage. We also discuss issues of maternal cell contamination, placental mosaicism and reciprocal and Robertsonian translocations in the context of interpretation of the results and genetic counseling.

Optimizing amniotic membrane tissue banking protocols for ophthalmic use.

Amniotic membrane (AM) due to its anti-inflammatory, anti-scarring and anti-angiogenic properties is used as corneal and wound grafts. When developing AM tissue banks, cell viability, membrane morphology and genomic stability should be preserved following cryopreservation. To analyze the changes rendered to the AM during the process of cryopreservation by comparing different combinations of standard cryopreservation media; fetal bovine serum (FBS), dimethyl sulfoxide (DMSO), Dulbecco's modified eagle's medium (DMEM) and glycerol at -80°C and at -196°C for a period of 6weeks and at 4°C in 70% alcohol for 6weeks. Following informed consent, placentae of healthy term pregnancies delivered by elective Cesarean section were collected and AM separated into 5×5cm size sections and under sterile conditions stored in 9:1 DMSO:FBS and 1:1 DMEM:Glycerol at -196 and -80°C for 6 weeks. Similar sections were also stored at 4°C in 70% alcohol for 6 weeks. After storage periods following were assessed; AM epithelial cell viability by trypan blue vital stain, epithelial cell proliferation capacity by cell doubling time, membrane morphology by haematoxylin and eosin (H&E) stain and genomic stability by conventional G-banded karyotyping. Human amniotic epithelial cells were cultured in DMEM and 10% FBS in humidified atmosphere of 5% carbon dioxide at 37°C and were characterized using RT-PCR for Octamer-binding protein 4 (Oct-4) and glucose-6-phosphate dehydrogenase (G6PD) genes. All the above parameters were also assessed in fresh AM. AM obtained from 4 term placentae. Mean cell count and mean cell doubling times in days respectively; for fresh AM 3.8×10(6); 1.59, after 6weeks in DMSO:FBS at -196°C 3.0×10(6); 2.38 and at -80°C 2.1×10(6); 1.60, in DMEM:Glycerol at -196°C 3.6×10(6); 2.33 at -80°C 23×10(6); 1.66 and at 4°C 3.3×10(6); 2.14. Histology analysis of the fresh AM showed an intact epithelial monolayer, thick basement membrane (BM) and avascular stromal matrix. Amniotic membranes stored at -196°C showed morphology similar to fresh AM in both preservation media and AM stored at -80°C showed disruption of the stromal matrix. At 4°C the epithelial monolayer showed flattening. Fresh AM karyotype was 46XX. Analyzable spreads for karyotype were not obtained from stored AMs. Human amniotic epithelial cells were positive for both Oct-4 and G6PD genes. AM is best preserved at -196°C either in 1:9 DMSO:FBS or 1:1 DMEM:Glycerol. In both conditions cell viability and membrane integrity were shown to be preserved up to 6weeks. Since analyzable chromosome spreads from cell cultures were not obtained, genomic stability could not be assessed.

1p36 deletion syndrome confirmed by fluorescence in situ hybridization and array-comparative genomic hybridization analysis.

Pediatric epilepsy can be caused by various conditions, including specific syndromes. 1p36 deletion syndrome is reported in 1 in 5,000–10,000 newborns, and its characteristic clinical features include developmental delay, mental retardation, hypotonia, congenital heart defects, seizure, and facial dysmorphism. However, detection of the terminal deletion in chromosome 1p by conventional G-banded karyotyping is difficult. Here we present a case of epilepsy with profound developmental delay and characteristic phenotypes. A 7-year- and 6-month-old boy experienced afebrile generalized seizure at the age of 5 years and 3 months. He had recurrent febrile seizures since 12 months of age and showed severe global developmental delay, remarkable hypotonia, short stature, and dysmorphic features such as microcephaly; small, low-set ears; dark, straight eyebrows; deep-set eyes; flat nasal bridge; midface hypoplasia; and a small, pointed chin. Previous diagnostic work-up, including conventional chromosomal analysis, revealed no definite causes. However, array-comparative genomic hybridization analysis revealed 1p36 deletion syndrome with a 9.15-Mb copy loss of the 1p36.33-1p36.22 region, and fluorescence in situ hybridization analysis (FISH) confirmed this diagnosis. This case highlights the need to consider detailed chromosomal study for patients with delayed development and epilepsy. Furthermore, 1p36 deletion syndrome should be considered for patients presenting seizure and moderate-to-severe developmental delay, particularly if the patient exhibits dysmorphic features, short stature, and hypotonia.

Establishment of Primary Adult MDS Nested Case-Control Study Cohort and Study of Risk Factors Associated with MDS Evolution to Leukemia

To establish a nested case-control study cohort in myelodysplastic syndrome (MDS) patients and investigate the clinical characteristics, WHO subtype and risk factors associated with MDS evolution to leukemia of this cohort. All patients, ≥18 years of age, provided by 24 Shanghai hospitals with initial clinical findings consistent with a hematopoietic abnormality between June 2003 and April 2007, were the candidates for inclusion in this study. The blood and bone marrow samples of every patient should be provided at baseline. Diagnosis was made by incorporating morphologic, immunophenotypic, cytogenetic and molecular features according to WHO classification criteria. Cytogenetic analysis was performed using conventional G-banding karyotyping and fluorescence in situ hybridization (FISH) techniques. Cumulative risk of evolution was estimated by Kaplan-Meier method. Prognostic factors were evaluated by univariate Log-rank method and multivariate Cox proportional hazard models. A total of 435 patients were diagnosed as MDS. The median age of MDS onset was 58(18-90) years, with 248 male patients and 187 female patients (male: female 1.33: 1). The percentage of cases with refractory cytopenia with multilineage dysplasia (RCMD) was the highest (65.5%), while that of refraetory anemia (RA) (2.3%), refractory anenia with ring sideroblast (RARS) (1.1%) and 5q-syndrome (0.5%) was lower. Trisomy 8 (+8) was the most common chromosome abnormalities (71 cases, 12.7%). The mean follow-up time was 20.3 (4.2-57.1) months. Cases were patients with evolution by the end of follow-up, while controls were patients without evolution by that time. Case group included 41 patients and control group included 342 patients. Univariate analysis showed that the age, sex, WHO subtype, WBC count, absolute neutrophil count (ANC), IPSS cytogenetic subgroup, IPSS group and bone marrow blast percentage were significant risk factors for leukemia-free survival (LFS). Multivariate analysis of COX model showed that the age, sex, WHO subtype, IPSS cytogenetic subgroup and bone marrow blast were independent risk factors for LFS. A nested case-control study cohort of MDS patients is established. The clinical characteristics and WHO subtype of MDS patients in Chinese Shanghai are different from that in Western countries. The independent risk factors for MDS evolution are age, sex, WHO subtype, IPSS cytogenetic subgroup and bone marrow blast percentage.