ABSTRACT
Justification: The diagnosis of Down syndrome (DS) is easily made clinically but the management is multi-disciplinary and life-long. There is no standard protocol available for its management in India. Process: A committee was formed under the Indian Academy of Pediatrics (IAP) chapter of Neuro developmental pediatrics consisting of 20 experts working in the related field. The various aspects of the condition were discussed and allotted to the concerned experts related for preparing the guidelines. The material received was collated to form a set of guidelines, which were reviewed by the committee, and a consensus statement made. The guidelines were then approved by the chapter, and by the IAP. Objectives: To define the condition and to look into the various aspects of antenatal and postnatal diagnosis. To explain briefly about the involvement of the various systems that are involved and formulate recommendations for management. To recommend early and sustained interventional therapies to enable children with DS lead an independent life. Recommendations: The stress on bio-psycho-social strategy for the management of children with DS is reiterated, and the need for a medical, social and rights model is recommended after each section. The age-wise recommendations are also highlighted in addition to the recommendations under each system.
ABSTRACT
Although non-invasive prenatal testing (NIPT) is widely used to detect fetal abnormalities, the results of NIPT vary by population, and data for the screening efficiency of NIPT positive predictive value (PPV) from different populations is limited. Herein, we retrospectively analyzed the NIPT results in a large multicenter study involving 52,855 pregnant women. Depending on gestational age, amniotic fluid or umbilical cord blood was extracted for karyotype and/or chromosome microarray analysis (CMA) in NIPT-positive patients, and the PPV and follow-up data were evaluated to determine its clinical value. Among the 52,855 cases, 754 were NIPT-positive, with a positivity rate of 1.4%. Karyotype analysis and/or CMA confirmed 323 chromosomal abnormalities, with a PPV of 45.1%. PPV for trisomy 21 (T21), trisomy 18 (T18), trisomy 13 (T13), sex chromosomal aneuploidies (SCAs), and copy number variations (CNVs) were 78.9, 35.3, 22.2, 36.9, and 32.9%, respectively. The PPVs for T21, T18, and T13 increased with age, whereas the PPVs for SCAs and CNVs had little correlation with age. The PPV was significantly higher in patients with advanced age and abnormal ultrasound. The NIPT results are affected by population characteristics. NIPT had a high PPV for T21 and a low PPV for T13 and T18, and screening for SCAs and CNVs showed clinical significance in southern China.
ABSTRACT
Objective:To investigate the clinical value of isolated fetal echogenic bowel (FEB) as an indicator for invasive prenatal diagnosis.Methods:This retrospective study enrolled 183 pregnant women who were diagnosed with isolated FEB and underwent invasive prenatal diagnosis in Fujian Maternity and Child Health Hospital from August 2013 to January 2021. Clinical data including the results of conventional karyotyping and chromosomal microarray analysis (CMA), cytomegalovirus (CMV) DNA loads in amniotic fluid and pregnancy outcomes were reviewed analyzed. Chi-square test was used for statistical analysis Results:Karyotyping was performed on all of the 183 fetuses and three (1.64%) aneuploidies (one case of trisomy 21, one trisomy 18 and one 47,XYY syndrome) were detected. One trisomy 21 and four pathogenic (P)/likely pathogenic (LP) copy number variation (CNV) were detected among 108 fetuses who received CMA. The detection rate of P/LP chromosomal abnormalities by CMA was higher than that by karyotyping, but there was no significant difference between them [4.63% (5/108) vs 0.93% (1/108), χ 2=1.54, P>0.05]. In addition, three cases of variants of uncertain significance (VOUS) were detected by CMA. CMV DNA loads of fetal cells in the amniotic fluid samples of the 166 cases were determined, and only one (0.6%) was positive (CMV DNA up to 7.01×10 6 copies/ml), and no abnormalities were found in karyotype analysis and CMA detection. A total of 176 cases were followed up, and among them only one case of intrauterine infection and seven cases (three aneuploidies and four P/LP CNV) of chromosomal abnormalities were terminated after genetic counseling. Three fetuses with VOUS and other 165 fetuses without chromosomal abnormalities had a good prognosis after birth. Conclusions:Isolated FEB may be the abnormal ultrasound finding in fetuses with chromosomal abnormalities or CMV infection. Prenatal genetic testing and the exclusion of intrauterine infection are important for management during pregnancy and prognosis assessment of FEB.
ABSTRACT
Objective:To explore the diagnostic value of chromosome karyotype analysis, chromosomal microarray analysis (CMA) and whole exome sequencing (WES) in microcephaly.Methods:A total of 9 cases of microcephaly fetuses diagnosed by prenatal ultrasound or children with microcephaly diagnosed after birth were selected from the Sixth Affiliated Hospital of Guangzhou Medical University from January 2014 to August 2022.Karyotype analysis and/or CMA were used to detect. The cases with negative karyotype analysis and CMA results were further sequenced by trio-based WES (Trio-WES). Then the coding genes contained in the pathogenic copy number variation (CNV) fragments were analyzed by gene ontology (GO) enrichment. The genes related to the development of the central nervous system contained in the pathogenic CNV and the pathogenic genes found by Trio-WES were combined for gene interaction network analysis.Results:In this study, 9 cases of microcephaly were recruited, with the time of diagnosis ranged from 23 weeks of gestation to 7 years after birth, and the head circumference of fetus or children ranged from 18.3 to 42.5 cm (-7SD to -2SD). Karyotype analysis was detected in all 9 cases and no abnormality result was found. Eight cases were detected by CMA, and one abnormal was found. Five cases were detected by Trio-WES, and two cases were detected with likely pathogenic genes. The GO enrichment analysis of the coding gene in the 4p16.3 microdeletion (pathogenic CNV) region showed that: in biological process, it was mainly concentrated in phototransduction, visible light; in terms of molecular function, it was mainly concentrated in fibroblast growth factor binding; in terms of cell components, it was mainly concentrated in rough endoplasmic reticulum. Gene interaction network analysis suggested that CDC42 gene could interact with CTBP1, HTT and ASPM gene.Conclusions:CMA could be used as a first-line detection technique for microcephaly. When the results of chromosome karyotype analysis and/or CMA are negative, Trio-WES could improve the detection rate of pathogenicity of microcephaly.
ABSTRACT
Objective:To explore the application value of chromosome karyotype analysis, chromosomal microarray analysis (CMA) and whole exome sequencing (WES) in prenatal diagnosis of isolated corpus callosum abnormality (CCA) fetus.Methods:Fetuses diagnosed with isolated CCA by ultrasound and MRI and receiving invasive prenatal diagnosis in Guangzhou Women and Children′s Medical Center and Qingyuan People′s Hospital from January 2010 to April 2021 were selected. Karyotype analysis and/or CMA [or copy number variation sequencing (CNV-seq)] were performed on all fetal samples, and WES was performed on fetal samples and their parents whose karyotype analysis and/or CMA (or CNV-seq) results were not abnormal.Results:Among 65 fetuses with isolated CCA, 38 cases underwent karyotype analysis, and 3 cases were detected with abnormal karyotypes, with a detection rate of 8% (3/38). A total of 49 fetuses with isolated CCA underwent CMA (or CNV-seq) detection, and 6 cases of pathogenic CNV were detected, the detection rate was 12% (6/49). Among them, the karyotype analysis results were abnormal, and the detection rate of further CMA detection was 1/1. The karyotype results were normal, and the detection rate of further CMA (or CNV-seq) detection was 14% (3/21). The detection rate of CMA as the first-line detection technique was 7% (2/27). A total of 25 fetuses with isolated CCA with negative results of karyotyping and/or CMA were tested by WES, and 9 cases (36%, 9/25) were detected with pathogenic genes. The gradient genetic diagnosis of chromosomal karyotyping, CMA and WES resulted in a definite genetic diagnosis of 26% (17/65) of isolated CCA fetuses.Conclusions:Prenatal genetic diagnosis of isolated CCA fetuses is of great clinical significance. The detection rate of CMA is higher than that of traditional karyotyping. CMA detection could be used as a first-line detection technique for fetuses with isolated CCA. WES could increase the pathogenicity detection rate of fetuses with isolated CCA when karyotype analysis and/or CMA test results are negative.
ABSTRACT
Objective:To analyze the type and characteristics of fetal cardiac abnormalities and their relationships with genetic abnormalities and clinical prognosis.Methods:The clinical data of 162 pregnant women with fetal cardiac abnormalities who came to the prenatal diagnosis center of Peking University First Hospital and performed genetic tests from February 2013 to February 2021 were reviewed. Genetic testing methods included chromosome karyotype analysis, array-based comparative genomic hybridization (aCGH) and pathogenic gene detection. Fetuses with isolated cardiac abnormalities and no fatal genetic abnormalities were assessed using the fetal cardiac birth defects clinical outcome score and followed up.Results:(1) Ultrasonography results: among the 162 fetuses, 86 cases (53.1%, 86/162) had isolated cardiac abnormalities, and 76 cases (46.9%, 76/162) had extra-cardiac abnormalities; single cardiac abnormalities were in 84 (51.9%,84/162) cases, and multiple cardiac abnormalities occurred in 78 cases (48.1%,78/162). (2) Genetic examination results: there were 39 cases (24.1%, 39/162) of pathogenic genetic abnormalities, including 35 cases (21.6%, 35/162) of pathogenic chromosome karyotype abnormality, 3 cases (1.9%, 3/162) of pathogenic copy number variant (CNV), and 1 case (0.6%, 1/162) of pathogenic gene variation. The detection rates of pathogenic genetic abnormalities were 16.3% (14/86) in fetuses with isolated cardiac abnormalities and 32.9% (25/76) in fetuses with cardiac abnormalities and extra-cardiac abnormalities, and the difference was statistically significant ( χ2=6.094, P=0.014). The detection rate of genetic abnormalities was 28.6% (24/84) in the single cardiac abnormalities, among which ventricular septal defect was 36.7% (11/30), atrioventricular septal defect was 8/13, tetralogy of Fallot was 3/17, persistent trancus arteriosus was 1/1, cardiac tumor was 1/1; no genetic abnormality was detected in the other single cardiac abnormality types (22 cases in total). The main types of pathogenic genetic abnormalities were trisomy 21 (41.7%, 10/24) and trisomy 18 (41.7%, 10/24). (3) Pregnancy outcome and fetal prognosis: among 72 fetuses with isolated heart abnormalities without pathogenic genetic abnormalities, there were 4 cases of grade Ⅰ, all of which continued pregnancy; 39 cases of grade Ⅱ, with 21 cases induced labor, 18 cases continued pregnancy; 26 cases of grade Ⅲ, with 23 cases induced labor, 3 cases continued pregnancy; 3 cases of grade Ⅳ, all of which induced labor. Totally, there were 47 cases induced labor and 25 cases continued pregnancy, 24 cases (96.0%, 24/25) of which were alive. Conclusions:When fetal cardiac abnormalities are detected by prenatal ultrasound, comprehensive cardiac and extra-cardiac ultrasound assessment and further genetic testing are recommended. Fetuses excluded pathogenic genetic abnormalities and extra-cardiac abnormalities should perform clinical prognostic score evaluation through multidisciplinary collaboration, to improve maternal and fetal outcomes.
ABSTRACT
Objective:To explore the application value of low depth and high-throughput gene sequencing in detecting chromosome copy number variations (CNVs) in different risk indicators of prenatal diagnosis.Methods:We retrospectively analyzed the genetic testing results of 1 597 pregnant women who underwent amniocentesis in Maternal and Child Health Care of Zaozhuang from January 2017 to December 2020 to obtain amniotic fluid cells and undergo high-throughput gene sequencing for chromosome copy number variation (CNV-seq). The CNV-seq results was compared with G-banding karyotype analysis.Results:The success rate of CNV-seq detection in 1 597 cases of amniotic fluid cells was 100%, and 301 cases of chromosomal CNVs were found, with an abnormal rate of 18.85%. Among them, 208 cases of chromosomal CNVs with definite pathogenicity accounted for 69.10%; There were 93 cases of CNVs with unknown pathogenicity, accounting for 30.90%. Among 208 cases of CNVs with definite pathogenicity, 166 cases had abnormal chromosome aneuploidy, accounting for 79.81%; 42 cases of chromosomal deletion / duplication structural abnormality, accounting for 20.19%. The detection of chromosomal copy number abnormalities in different prenatal diagnosis indicators was different. The incidence of chromosomal CNVs in the NIPT screening risk group was the highest (53.09%, 163/307), followed by the ultrasonic structural abnormality group (22.38%, 32/143), the chromosomal abnormality carrying group (12.50%, 5/40), the other abnormality group (11.34%, 22/194), the serological prenatal screening high-risk group (9.04%, 74/819), and the elderly group (5.32%, 5/94). Compared with G-banding karyotype analysis, CNV-seq has a detection rate of 100% for 166 cases of chromosomal aneuploidy and 13 cases of unbalanced chromosomal structural abnormalities confirmed by G-banding karyotype analysis. In addition, and more pathogenicity specific chromosomal microdeletions / microduplication abnormalities can be found by CNV-seq.Conclusions:CNV-seq has high success rate and short time-consuming in the detection of chromosome CNVs, which can effectively avoid the failure of karyotype analysis and the problem of time-consuming; Moreover, CNV-seq can also find additional CNVs with clear pathogenicity, improve the positive detection rate, and effectively prevent the birth of defective children. Therefore, pregnant women with different prenatal diagnosis indications should be tested with CNV-seq at the same time of amniotic fluid karyotype analysis. CNV-seq can be used as a first-line auxiliary diagnostic technology in prenatal diagnosis for clinical application.
ABSTRACT
Objective:To explore the value of karyotyping and chromosomal microarray analysis (CMA) in the prenatal diagnosis of balanced translocation/inversion carriers.Methods:This was a retrospective study involving 117 balanced translocation/inversion carrier couples. Among them, 90 women had a history of spontaneous abortion(≥2 times), stillbirth, fetal multiple malformations, or giving birth to children with chromosome abnormality disease and the peripheral blood karyotyping and fluorescence in situ hybridization testing confirmed that one partner was balanced translocation/inversion carrier. The present pregnancies of these cases were spontaneous and lasted until 18-25 weeks. The other 27 cases were confirmed by chromosome examination at the present pregnancy after the indication of fetal structural abnormalities by fetal karyotyping due to advanced maternal age and abnormal ultrasound and prenatal screening results. The results of karyotyping and CMA by amniocentesis during 18 to 25 gestational weeks were all summarized and described. Results:The successful rate of both methods was 100.0% (117/117). Unbalanced and balanced translocation/inversion were detected in seven (6.0%) and 39 (33.3%) fetuses by karyotyping, respectively. CMA revealed 14 fetuses with pathogenic copy number variation (CNV) and one with variants of uncertain significance(VUS), with an anomaly detection rate of 12.8% (15/117). Among the 15 cases with CNV, 13 were related to the parental translocation/inversion, one with de novo mutation (22q11.2 microdeletion syndrome), and one Duchenne muscular dystrophy mutation carrier. Based on the results of karyotype and CMA, there were 12 fetuses with unbalanced chromosomal fragments (10.3%), 37 fetuses with balanced translocation/inversion (31.6%), and 68 fetuses with normal chromosomes (58.1%). Conclusions:The combination of karyotyping and CMA can provide more accurate prenatal genetic diagnosis when one of a couple carries balanced chromosomal translocations/inversion.
ABSTRACT
Objective:To explore the genetic etiology of fetuses with high suspicion of congenital skeletal malformation detected by prenatal ultrasound.Methods:This retrospective study collected 21 pregnant women with highly suspected fetal skeletal malformation indicated by ultrasound (the couples had no skeletal malformation) at Institute of Medical Genetics, Henan Provincial People's Hospital from January 2019 to August 2020. Amniotic fluid/umbilical cord blood of the fetus and peripheral blood of the couples were obtained for karyotype analysis, chromosomal microarray analysis, and whole-exome sequencing. Sanger sequencing was performed for the "pathogenic" "suspected pathogenic" "variants of uncertain significance" variants detected by whole exome sequencing. Genetic etiology of the 21 fetuses was described.Results:A total of five chromosomal abnormalities were detected, including four cases of trisomy 21 and one trisomy 18. Chromosome microarray analysis detected one case of abnormal copy number variation, 16 p11.2 microdeletion syndrome. Ten cases of monogenic diseases were found by whole exome sequencing and eight genes were involved ( SGMS2, FGFR3, DYNC2H1, WDR35, TBX5, COL2A1, FGFR2, and ALPL). Totally, 14 variations were detected, among which seven were novel variations (c.8129T>A, c.7126G>A, c.10307_10320del, and c.2641G>T in DYNC2H1 gene; c.3085G>A and c.491G>A in WDR35 gene; c.1070G>T in COL2A1 gene). Conclusions:For fetus, whose parents have no skeletal malformation, highly suspected of congenital malformation of skeletal system by prenatal ultrasound, genetic factor is the primary reason, including chromosomal abnormalities, copy number variations, and monogenic mutations.
ABSTRACT
Objective:To investigate the prenatal genetic features and the factors influencing the prognosis of twin reversed arterial perfusion sequence (TRAPS) in monochorionic twin pregnancies.Methods:A total of 99 cases diagnosed with TRAPS by prenatal ultrasound in the First Affiliated Hospital of Sun Yat-sen University from July 1, 2007, to December 31, 2021, were included retrospectively. The prenatal genetic features of acardiac and pump twins were analyzed. Eighty-nine cases were followed up and divided into two groups: the expectation group ( n=45) and the intrauterine intervention group (all underwent radiofrequency ablation, n=44) and the pregnancy outcomes were compared between the two groups. After excluding eight cases without complete ultrasound data, the expectation group was further divided into two subgroups: the pump fetus survival ( n=28) and the pump fetus death groups ( n=9), and the survival subgroup was divided into the spontaneous arrest group ( n=16) and coexistence group ( n=12) according to whether or not the blood flow stopped spontaneously.The relationship between ultrasonic indexes and pregnancy outcome was compared between the groups. Chi-square test (or Fisher's exact test), univariate logistic regression analysis and receiver operating characteristic (ROC) curve were used to analyze the relationship between the estimated acardiac to pump twin weight ratio (A/P Wt) and the pregnancy outcome of the pump twin in the expectation group. Results:(1) The median gestational age at diagnosis of the 99 TRAPS cases was 16.4 weeks (13.3- 21.3 weeks) and 32% (32/99) were diagnosed in the first trimester. Most of the cases were monochorionic diamniotic pregnancies (72/99, 73%). The survival rate of the pump twins was 71% (63/89). (2) Chromosome karyotyping and/or chromosomal microarray analysis was performed in 19 acardiac twins and 82 pump twins. The detection rate of genetic abnormalities in the acardiac twins was higher than that in the pump twins [4/19 vs 5% (4/82), Fisher's exact test, P=0.039]. Chromosomal microarray analysis was performed in 54 pump twins with normal karyotypes and the results showed three (6%) with genetic abnormalities. (3) In the expectation group, the area under ROC curve for the prenatal A/P Wt were 0.913 in predicting pump twin death and 0.807 in predicting spontaneous cessation of blood flow in the cardiac twin, and the cut-off values were 0.24 (sensitivity: 88.9%, specificity: 96.4%) and 0.11 (sensitivity: 75.0%, specificity: 81.3%), respectively. The survival rate of pump twins with abnormal cardiac function after intrauterine intervention was higher than that of the expectant group [72% (18/25) vs 3/11, Fisher's exact test, P=0.025]. Conclusions:TRAPS can be diagnosed in the first trimester and commonly occur in monochorionic diamniotic pregnancies. The detection rate of genetic abnormalities in the acardiac twins is higher than that in the pump twins. Prenatal A/P Wt>0.24 indicates the death of the pump twin and prenatal A/P Wt≤0.11 suggests a high possibility of spontaneous cessation of blood flow in the acardiac twin. Radiofrequency ablation is an effective method for improving the prognosis of the pump twin with cardiac dysfunction.
ABSTRACT
Objective:To explore the application value of copy number variation sequencing(CNV-seq) combined with chromosome karyotyping technology based on next-generation sequencing technology in prenatal diagnosis.Methods:The subjects of the study were 329 pregnant women who underwent prenatal diagnosis at Dalian Municipal Women and Children′s Medical Center from January 2019 to June 2020. The amniotic fluid samples of these pregnant women were submitted for chromosome karyotype analysis, and CNV-seq testing was performed at the same time to compare the test results of the two methods.Results:A total of 53 cases of abnormal chromosomes were detected using CNV-seq combined with chromosome karyotyping technology, with an abnormal detection rate of 16.11%(53/329). Among them, 26 cases had consistent detection results, including 22 cases of aneuploidy, 2 cases of structural abnormalities and 2 cases of mosaic; CNV-seq detected 23 cases of chromosome copy number variations that were missed by karyotyping, including 17 cases of microdeletion and 6 cases of microduplication; chromosome karyotype analysis detected 4 cases of chromosome structural abnormalities that were missed by CNV-seq, including 3 cases balanced translocation and 1 case of inversion.Conclusions:CNV-seq has obvious advantages in detecting copy number variations of small fragments, which can make up for the lack of resolution of karyotyping analysis; CNV-seq combined with chromosome karyotyping analysis can improve the detection rate of abnormal chromosomes, which is important for prenatal diagnosis meaning.
ABSTRACT
Human chromosomes karyotyping is an important means to diagnose genetic diseases. Chromosome image type recognition is a key step in the karyotyping process. Accurate and efficient identification is of great significance for automatic chromosome karyotyping. In this paper, we propose a model named segmentally recalibrated dense convolutional network (SR-DenseNet). In each stage of the model, the dense connected network layers is used to extract the features of different abstract levels of chromosomes automatically, and then the concatenation of all the layers which extract different local features is recalibrated with squeeze-and-excitation (SE) block. SE blocks explicitly construct learnable structures for importance of the features. Then a model fusion method is proposed and an expert group of chromosome recognition models is constructed. On the public available Copenhagen chromosome recognition dataset (G-bands) the proposed model achieves error rate of only 1.60%, and with model fusion the error further drops to 0.99%. On the Padova chromosome dataset (Q-bands) the model gets the corresponding error rate of 6.67%, and with model fusion the error further drops to 5.98%. The experimental results show that the method proposed in this paper is effective and has the potential to realize the automation of chromosome type recognition.
Subject(s)
Humans , Chromosomes , Neural Networks, ComputerABSTRACT
Background: Anorectal malformations (ARM) are congenital malformations of digestive system resulting from the disturbed development of hindgut during embryogenesis. ARMs involve both sexes; can occur either isolated or in association with other congenital abnormalities and may be associated with chromosomal abnormalities. Association of trisomy 21 with anorectal malformation is well documented. Present study was conducted to assess prevalence of association of trisomy 21 in patients with anorectal malformation.Methods: Total 48 children with diagnosis of anorectal malformation, who were admitted in Department of Paediatric Surgery, King George’s Medical University, Lucknow, Uttar Pradesh, were selected for the study. Blood samples were collected and their cytogenetic analysis was carried out in the Cytogenetics laboratory, Department of Anatomy, KGMU-U.P, Lucknow, India.Results: Among the 48 study subjects, karyogram could be successfully obtained for 45 cases (93.75%). Numerical anomalies were observed in 8.9% cases. Trisomy 21 was found in 6.7%. The prevalence of trisomy 21 was found to more in males (4.5%) as compared to females (2.2%). Prevalence was highest in birth order 3(20%), followed by birth order 2(7.14%) and lowest in birth order 1(3.85%). Trisomy in association with ARM; was observed in children born to females aged >30 years. It was found unrelated to the history of consanguinity.Conclusions: Prevalence of association of trisomy 21 with ARM was found to be 6.7%. This coexistence emphasizes the need for a thorough investigation of patients with ARM.
ABSTRACT
@#Emanuel syndrome, also referred to as supernumerary der(22) or t(11;22) syndrome, is a rare genomic syndrome. Patients are normally presented with multiple congenital anomalies and severe developmental disabilities. Affected newborns usually carry a derivative chromosome 22 inherited from either parent, which stems from a balanced translocation between chromosomes 11 and 22. Unfortunately, identification of Emanuel syndrome carriers is difficult as balanced translocations do not typically present symptoms. We identified two patients diagnosed as Emanuel syndrome with identical chromosomal aberration: 47,XX,+der(22)t(11;22)(q24;q12.1)mat karyotype but presenting variable phenotypic features. Emanuel syndrome patients present variable phenotypes and karyotypes have also been inconsistent albeit the existence of a derivative chromosome 22. Our data suggests that there may exist accompanying genetic aberrations which influence the outcome of Emanuel syndrome phenotypes but it should be cautioned that more patient observations, diagnostic data and research is required before conclusions can be drawn on definitive karyotypic-phenotypic correlations.
ABSTRACT
Cytogenetics is the study of chromosomes; their structure and properties, chromosome behavior during cell division, their influence on traits and factors which cause changes in chromosomes. Veterinary cytogenetics is the application of cytogenetics to clinical problems that occur in animal production. It has been applied to understand problems such as infertility and its types, embryonic and fetal death, abnormality in sexual and somatic development and hybrid sterility and also prenatal sex determination and other forms of chromosomal abnormalities. These are achieved through conventional and banded karyotyping techniques and molecular cytogenetic techniques. Although conventional techniques are still useful and very widely applied, the nature of cytogenetics has gradually changed as a result of advances achieved in the molecular cytogenetic techniques for example fluorescent in situ hybridization and array-based techniques. These changes are evident in both molecular diagnostics and basic research. The combination of conventional and molecular cytogenetics has given rise to high resolution techniques which have enabled the study of fundamental questions regarding biological processes. It enables the study of inherited syndromes, the mechanisms of tumorigenesis at molecular level, genome organization and the determination of chromosome homologies between species. It allows the ease with which animals are selected in breeding programs and other important aspects of animal production. In this paper we discussed a number of techniques employed in cytogenetics and their methodologies, and recommend where future focus should be for the benefits of animal production.
ABSTRACT
Although it is known that the parental carriers of chromosomal translocation are considered to be at high risk for spontaneous abortion and embryonic death, normal gestation and delivery remain possible. This study aims to investigate the genetic factors of a Chinese infant with multiple malformations and severe postnatal development retardation. In this study, the routine cytogenetic analysis, chromosomal microarray analysis (CMA) and fluorescence in situ hybridization (FISH) analysis were performed. Conventional karyotype analyses revealed normal karyotypes of all family members. CMA of the DNA of the proband revealed a 8.3Mb duplication of 5q35.1-qter and a 6.9Mb deletion of 11q24.3-qter. FISH analyses verified a paternal tiny translocation between the long arm of chromosomes 5 and 11. Our investigation serves to provide important information on genetic counselling for the patient and future pregnancies in this family. Moreover, the combined use ofCMAand FISH is effective for clarifying pathogenically submicroscopic copy number variants.
ABSTRACT
A obtenção de cariótipos de peixes desempenha um papel importante em estudos de citotaxonomia e evolução cromossômica das espécies. No entanto, poucos sistemas semi ou completamente automatizados para a obtenção de cariótipo de peixes estão disponíveis. Este trabalho propõe e avalia uma ferramenta baseada em imagens que auxilie a montagem de cariótipos de peixes. As espécies analisadas foram Hopliasmalabaricus (Bloch, 1794); Hypostomusancistroides (Ihering, 1911) e Parauchenipterusgaleatus (Linnaeus, 1766); popularmente conhecidas como traíra, cascudo e bagre-sapo, respectivamente.Um total de 100 metáfases foi analisado por dois métodos: 1 - geração semiautomática de cariótipo e 2 - geração automática de cariótipo. A avaliação do sistema foi feita por meio da correlação de Pearson, gráficos de diferenças e tabelas de contagens,utilizando-se como referência a média das contagens feitas por quatro usuários. No método 1, quatro usuários realizaram contagens e apresentaram correlação interobservador de r≥ 0.997. O número total de cromossomos identificados pelo método 1 foi 4348 e, para o método 2, foi 4135,o que resultou em uma identificação automática de aproximadamente 95,1% dos cromossomos, resultando em correlação entre os dois métodos de r= 0.93. Conclui-se que a ferramenta pode ser inserida no procedimento de cariotipagem de peixes para acelerar o processo com níveis aceitáveis de exatidão.(AU)
Fish karyotyping plays an important role in studies of cytotaxonomy and chromosomic evolution of species. However, few semi or completely automated fish karyotyping systems are available. This work proposes and evaluates an image-based tool to assist fish karyotyping. The analyzed species were Hopliasmalabaricus (Bloch, 1794), Hypostomusancistroides (Ihering, 1911), and Parauchenipterusgaleatus (Linnaeus, 1766). In Portuguese, these species are commonly referred to as traíra, cascudo, and bagresapo, respectively. A total of 100 metaphases were analyzed through two methods: (1) semi-automatic karyotype generation and (2) automatic karyotype generation. The results were analyzed using Pearson correlation, difference graphs and counting tables. The reference used for the evaluation of the system was the average of the counts made by four experts. In method 1, four users performed counts with interobserver correlation of r≥ 0.997. The total number of chromosomes identified by method 1 was 4348 and method 2 was 4135, excluding false positives, resulting in an automatic identification of approximately 95,1% of the chromosomes, resulting in a correlation between the methods of r= 0.93. The results indicate that the tool can be introduced for fish karyotyping procedures contributing for accelerating the process with acceptable accuracy.(AU)
Subject(s)
Fishes/geneticsABSTRACT
Introduction: Aims: To identify the Anorectal malformations patients in North Indian region and then study the karyotype of these patients to evaluate cytogenetic aberrations and then correlate it with the maternal age. Subjects and Methods: Forty eight patients of anorectal malformation were selected from Department of Paediatric Surgery, KGMU, UP, Lucknow. Blood samples were collected and their cytogenetic study was done in the Department of Anatomy, KGMU-U.P, Lucknow. Karyotypes obtained were further analysed. Results: Out of 48 children enrolled in the study, karyogram could be obtained for 45 cases (93.75%). Maternal age at the time of birth of the child was <30 years in 91.1% cases. There were only 8.9% women who were >30 years of age at the time of birth of the child. However, proportion of those with anomalies was significantly higher in >30 years age group (75%) as compared to that in <30 years age group (2.4%). Conclusion: Although low maternal age was found most commonly, but number of cases with chromosomal anomalies was reported more in >30 years of age, which could be due to increased risk of congenital anomalies and malformations with advanced age.
ABSTRACT
Objective@#To investigate the value of karyotype analysis, bacterial artificial chromosomes-on-beads (BoBs), chromosome microarray analysis (CMA) and fluorescence in situ hybridization (FISH) in the diagnosis of sex chromosome numerical and structural abnormalities.@*Methods@#Conventional G-banding staining technique was used to analyze the karyotypes of amniotic fluid cells and parental peripheral blood cells in two pregnancies with prenatal diagnosis indications. Sex chromosome numerical and structural abnormalities were analyzed based on the results of G-banding, BoBs, CMA and FISH.@*Results@#The results of G-banding karyotype analysis showed that there were mosaics in amniotic fluid cells collected from both cases. Karyotype of Case A was 45,X[25]/46,X,idic(Y)(q11.2?)[6], and Case B was 45,X[39]/46,X,psu idic(X)(q21.32?)[44]. Parental peripheral blood karyotypes of both families were normal. Prenatal BoBs indicated copy number abnormalities in sex chromosomes (Y chromosome in Case A and X chromosome in Case B). CMA results suggested a 20.1 Mb duplication in Yp11.32q11.222, and a 7.7 Mb deletion in Yq11.222q11.23 in fetus A with possible karyotype of 46,X,idic(Y)(q11.222); for fetus B, a 92.0 Mb duplication in Xp22.33q21.32, and a 63.0 Mb deletion in Xq21.32q28 were detected, and the karyotype might be 46,X,psu idic(X)(q21.32). The mid-term FISH test of amniotic fluid cells showed that 90% of the amniotic cells from Case A were 45,X, and 10% were 46,X,idic(Y)(q11.2); about 38% were 45,X, and 62% were 46,X,psu dic(X)(q21.3) from Case B.@*Conclusions@#Numerical and structural abnormalities of sex chromosomes could be accurately diagnosed by combination of several methods including G-banding karyotype analysis, prenatal BoBs, CMA and FISH, which would help to effectively reduce birth defects.