Gestação em idade avançada e aconselhamento genético: um estudo em torno das concepções de risco / Advanced maternal age pregnancy and genetic counseling: a study on the concept of risk

Resumo As inovações científicas em torno do estudo de cromossomos humanos surgidas após a segunda metade do século XX consolidaram a inserção da genética na assistência em saúde, no que tange ao diagnóstico pré-natal. A associação entre idade materna e síndromes genéticas, proposta por pesquisadores da biomedicina, produziu determinações sobre risco, referidas a gestantes a partir de determinada idade. O artigo apresenta as concepções de risco em torno do que a biomedicina considera ser idade materna avançada de modo a configurar o que é classificado como gestação de risco. A análise documental em manuais médicos brasileiros e estrangeiros das especialidades obstetrícia e genética evidenciou diferentes concepções de risco em relação ao fator etário reprodutivo. A idade materna é um aspecto presente na obstetrícia enquanto fator de risco de doenças. Para a especialidade genética, a idade materna não é um fator central de risco reprodutivo. A pesquisa constatou que a classificação de uma idade materna ideal para gestar é relativa e suscetível a alterações, segundo o contexto sócio-histórico de cada sociedade.

Abstract Scientific innovations around the study of human chromosomes, which emerged after the mid 20th century, consolidated the incorporation of genetics in prenatal diagnosis. The link between maternal age and genetic syndromes, proposed by biomedical researchers, produced resolutions about risks to pregnant women of a certain age. The article presents biomedicine concepts for advanced maternal age classified as a risk pregnancy. The review of Brazilian and foreign medical manuals in obstetrics and genetics showed different conceptions of risk concerning the reproductive age factor. Maternal age is an aspect in obstetrics related to the risk of diseases. For genetic expertise, advanced maternal age is not a central factor of risk for reproduction. The research found that the classification of an ideal maternal age for pregnancy is relative and susceptible to changes according to the socio-historical context of each society.

Mutação de novo no gene DEAF1 e sua relação com o autismo: estudo de caso / De novo mutation in the DEAF1 gene and its relation to autism: a case study / Mutación de nuevo en el gen DEAF1 y su relación con el autismo: estudio de caso

Objetivo: Analisar as implicações, impactos e o desenvolvimento de um indivíduo diagnosticado com TEA e portador da mutação de novo no gene DEAF1, a partir das várias perspectivas de intervenções realizadas. Método: Trata-se de um estudo descritivo com histórico dos tratamentos, resultados laboratoriais e genéticos mais recentes do paciente. Resultados: Sintomas notados aos 2 anos e diagnóstico específico aos 5. Aos 8 anos teve a primeira crise convulsiva tônico-clônica e o Eletroencefalograma alterado. Após obteve o diagnóstico molecular confirmado. Possuía epilepsia refratária de difícil controle, que houve piora com uma tentativa do uso de derivados canabinoides em conjunto com estimulação elétrica transcraniana. No momento, com os tratamentos, atendimentos multidisciplinares, dieta de exclusão de alérgenos e medicações de controle individual, diminuíram a intensidade das crises epiléticas e houve melhor controle do seu estado geral. Conclusão: Este estudo descreve como a mutação de novo no gene DEAF1 está relacionada com o TEA e com o comprometimento do desenvolvimento neurocognitivo. As terapias e métodos devem respeitar cada paciente na sua individualidade.

Objective: To analyze the implications, impacts and development of an individual diagnosed with ASD and carrying a de novo mutation in the DEAF1 gene, from the various perspectives of interventions performed. Method: This is a descriptive study, with the patient's history of treatments, and most recent laboratory and genetic results.Results: Symptoms were noticed at 2 years old and specific diagnosis at 5. At 8 years old he had his first tonic-clonic seizure and the electroencephalogram was altered. After, it was obtained the confirmed molecular diagnosis. He had refractory epilepsy that was difficult to control and aggravated with an attempt to use cannabinoid derivatives in conjunction with transcranial electrical stimulation. At the moment, treatments, multidisciplinary care, allergen exclusion diet and individual control medications, reduced the intensity of epileptic seizures and there was better control of his general condition. Conclusion: This study describes how the de novo mutation in the DEAF1 gene is related to ASD and neurocognitive development impairment. Therapies and methods must respect each patient in their individuality.

Objetivo: Analizar las implicaciones, impactos y desarrollo de un individuo diagnosticado de TEA y portador de una mutación de novo en el gen DEAF1, desde las distintas perspectivas de las intervenciones realizadas. Método: Este es un estudio descriptivo, con el historico de tratamientos del paciente y los resultados genéticos y de laboratorio más recientes. Resultados: Los síntomas se notaron a los 2 años y el diagnóstico específico a los 5. A los 8 años tuvo su primera crisis tónico-clónica y se alteró el electroencefalograma. Posteriormente se obtuvo el diagnóstico molecular confirmado. Tenía epilepsia refractaria que era difícil de controlar y se agravaba con un intento de utilizar derivados cannabinoides junto con estimulación eléctrica transcraneal. En el momento, los tratamientos, la atención multidisciplinar, la dieta de exclusión de alérgenos y los medicamentos de control individual, redujeron la intensidad de las crisis epilépticas y hubo un mejor control de su estado general. Conclusión: Este estudio describe cómo la mutación de novo en el gen DEAF1 se relaciona con el TEA y el deterioro del desarrollo neurocognitivo. Las terapias y los métodos deben respetar a cada paciente en su individualidad.

Análisis citogenético en linfocitos de trabajadores expuestos a radiación ionizante en una unidad de cardiología intervencional de Chile: estudio piloto y revisión de la literatura / Citogenetic effects upon lymphocyes in subjects exposed to ionizing radiadion in an interventional laboratory cardiology: pilot study and literature review

ANTECEDENTES: Un número creciente de artículos está llamando la atención en forma consistente sobre la eventual asociación que existe entre los denominados trabajadores ocupacionalmente expuestos a bajos niveles de radiación ionizante (POEs) y una mayor frecuencia de aberraciones cromosómicas, a nivel Sudamericano estos estudios son escasos. OBJETIVO: Evaluar la frecuencia de aberraciones cromosómicas en linfocitos de sangre periférica de POEs de un hospital y de sujetos sanos. Adicionalmente, se realizó una revisión exhaustiva de los artículos que a la fecha abordaron este tema. MATERIAL Y MÉTODO: Se condujo un análisis citogenético destinado a cuantificar las aberraciones cromosómicas en sangre periférica de linfocitos de 6 POEs de la unidad de Cardiología Intervencional y, como controles, 6 muestras de sujetos de la población general fueron analizadas. RESULTADOS: Se observó un importante contraste en el número de aberraciones cromosómicas presentadas en los POEs versus la población general no expuesta a radiaciones ionizantes, siendo esta de una relación de 6:1, respectivamente. CONCLUSIÓN: Los resultados preliminares indican una mayor frecuencia de aberraciones cromosómicas en los POEs versus la población general, sin embargo, se deberá esperar los resultados de la segunda fase de investigación, donde al ampliar la muestra en análisis se podrán obtener conclusiones estadísticamente significativas.

BACKGROUND: There is growing evidence of an increased number of chromosomes aberrations in subjects exposed to low levels of ionizing radiation (POEs). There are few studies on this subject in Latin America AIM: To evaluate the frequency of chromosome aberrations in lymphocytes obtained from peripheral blood in subjects working in laboratories where low levels of ionizing radiation are present and to compare these findings to those of unexposed subjects. METHODS: A cytogenic analysis to quantify chromosome aberrations was performed in 6 POs subjects from a cardiology invasive laboratory and 6 controls from a general unexposed population. RESULTS: Compared to controls, an approximately 6-fold increase in the number of chromosome aberrations was observed.in subjects exposed to ionizing radiation CONCLUSION: These preliminary results indicate that there is an increased number of chromosome aberrations in subjects exposed to low levels of ionizing radiation, as occurs in people working in a cardiology interventional laboratory. Studies in large numbers of subjects and preferably followed prospectively are needed to evaluate more precisely this effect.

Síndrome de Down por mosaico, reporte de caso Ecuador / Mosaic Down syndrome, case report Ecuador

El síndrome de Down, es una de las principales causas de discapacitada intelectual relacionada a alteraciones en los cromosomas humanos, el síndrome de Down por mosaísmo es uno de los tres tipos de alteración cromosómica que se presentan en estos pacientes, encontrándose en 1% al 4% de los casos reportados de este síndrome, en los cuales las características físicas son casi imperceptibles a una simple valoración. Presentamos el caso clínico de paciente masculino de 9 meses de edad que acudió a valoración médica por retraso leve madurativo e infecciones respiratorias a repetición.

Down syndrome is one of the main causes of intellectual disability related to alterations in human chromosomes. Mosaic Down syndrome is one of the three types of chromosomal alteration that occurs in these patients, being 1% at 4% of the reported cases of this syndrome, in any of the physical characteristics are almost imperceptible to a simple assessment. We present the clinical case of a 9-month-old male patient who attended a medical evaluation for mild maturational delay and repeated respiratory infections.

Characteristics of a patient with myeloid neoplasm and co-existence of t(7;11)(p15;p15) and t(5;12)(q33;p13) translocations / 中华医学遗传学杂志

OBJECTIVE@#To delineate the clinical and molecular characteristics of a patient with myeloid neoplasm and co-existence of t(7;11)(p15;p15) and t(5;12)(q33;p13) translocations.@*METHODS@#Clinical data of the patient was collected. Conventional karyotyping, reverse transcriptase (RT)-PCR and next generation sequencing (NGS) were carried out to delineate its genetic features.@*RESULTS@#The patient has featured recurrent rash, fatigue, loss of appetite and splenomegaly. Laboratory test suggested hyperleukocytosis of FAB-M2-subtype. Neither eosinophilia nor basophilia was presented. NUP98/HOXA9 and ETV6/PDGFRB fusion genes were detected by RT-PCR. NGS and DNA-PCR showed the co-existence of WT1 p.C423Y, KRAS p.G12D and DNMT3A p.R882C mutations. The patient achieved morphological remission after imatinib plus coventional chemotherapy (standard IAC regimen). However, the disease has relapsed shortly after. Treatment was switched to HHT-Ara-C-Acla regimen, no hematological response was observed. The ETV6/PDGFRB fusion gene was undetectable in bone marrow sample, though strong expression of NUP98/HOXA9 was detectable throughout the whole course.@*CONCLUSION@#Acute myeloid leukemia in association with the co-existence of NUP98/HOXA9 and ETV6/PDGFRB fusion genes have unique clinical and genetic features. Imatinib seems to have no impact on the overall survival in such cases.

Co-occurrence of t(8;21)(q22;q22) and t(9;22)(q34;q11) in a case with chronic myelogenous leukemia / 中华医学遗传学杂志

OBJECTIVE@#To delineate laboratory and clinical characteristics of a case with chronic myelogenous leukemia (CML) and co-occurrence of t(9;22)(q34;q11) and t(8;21)(q22;q22).@*METHODS@#The patient was subjected to cytogenetic, molecular, morphological and immunophenotypic analyses.@*RESULTS@#Cytogenetic analysis revealed presence of t(8;21)(q22;q22) in addition to t(9;22)(q34;q11) in the patient. Chimeric BCR/ABL and AML1/ETO genes were detected by fluorescence in situ hybridization (FISH). Transcripts of BCR/ABL210 and AML1/ETO fusion genes were detected by relative quantity PCR. Morphological study suggested that the patient was at the chronic phase of CML. No significant immunophenotypic abnormality was detected by flow cytometry.@*CONCLUSION@#Co-occurrence of t(8;21)(q22;q22) and t(9;22)(q34;q11) is rare in CML. Only 5 similar cases have been described previously. This case suggested that chromosomal alterations may precede morphological, flow cytometric and clinical changes and accelerate progression of the disease.

Diagnosis of a fetus with partial 17p trisomy using chromosomal microarray analysis / 中华医学遗传学杂志

OBJECTIVE@#To use single nucleotide polymorphism microarray (SNP array) to screen whole genome copy number variations (CNVs) in a fetus with multiple malformation.@*METHODS@#Amniotic fluid sample was subjected to routine G banding chromosomal analysis and CNVs detection, and its parents were tested in order to determine the origin of fetal chromosomal aberration.@*RESULTS@#SNP array has detected a large fragment repetition spanning approximately 16 Mb in the 17q24.2-q25.3 region in the fetus. The karyotype of amniotic fluid was 46,XY,der(21),t(17;21)(q23;p12). The karyotype of the mother was normal, while its father has a karyotype of 46,XY,t(17;21)(q23;p12).@*CONCLUSION@#The large repetition at 17q24.2-q25.3 probably underlies the multiple fetal malformation. Abnormal fetuses carrying apparently balanced chromosomal translocations may harbor CNVs outside the breakpoint regions involved in the rearrangements. SNP array has provided a useful supplement for the conventional G banding karyotyping analysis.

Prenatal diagnosis of a fetus with trisomies of 11q23.3q25 and 22q11.1q11.21 / 中华医学遗传学杂志

OBJECTIVE@#To explore the phenotype and pathogenesis of a fetus with a rare chromosomal abnormality.@*METHODS@#The fetus was analyzed by clinical prenatal ultrasonography, G-banding karyotyping and next generation sequencing (NGS).@*RESULTS@#Prenatal ultrasonography of the fetus showed Dandy-Walker syndrome, growth restriction, and right-heart system dysplasia. The fetus had a chromosomal karyotype of 47,XY,t(11;22)(q23.3;q11.2),+der(22)t(11;22). Duplication of 11q23.3q25 and 22q11.1q21 were also detected by NGS. The chromosomal translocation carried by the fetus was derived from his father.@*CONCLUSION@#Duplications of chromosome 11q23.3q25 and 22q11.1q11.21 segments probably underlie the Dandy-Walker syndrome, growth restriction, and hypoplasia of the right heart system in the fetus.

Optimization of chromosome flaking technique for mesenchymal stem cells / 中华医学遗传学杂志

OBJECTIVE@#To optimize the condition for chromosome flaking of mesenchymal stem cells to ensure the cytogenetic quality control of expanding production and clinical application.@*METHODS@#Chromosomal flaking methods were optimized from current chromosome preparation techniques from the aspects of MSCs cell culture concentration, colchicine treatment time and low permeability time.@*RESULTS@#By repeated pre-experiments, the optimal MSCS chromosome flaking condition of MSCs was determined as cell culture concentration of (1-2)× 10 cells per T25 cell culture bottle, and the colchicines processing time was determined as 2 hours and 10 minutes, and the low permeability was 1 hour.@*CONCLUSION@#The optimized chromosome flaking condition can fulfill the requirement of cytogenetic quality control for MSCs.

Ventajas y limitaciones de la citogenética en la medicina actual / Advantages and limitations of cytogenetics in current medicine

La citogenética es el estudio de los cromosomas tanto en número como en estructura. En 1882 Flemming publica las primeras primeras ilustraciones de los cromosomas humanos a partir de observaciones al microscopio y recién en el año 1953, Tjio y Levan determinaron el número real de cromosomas humanos por célula diploide (2n=46). El propósito de este trabajo es presentar el valor, uso actual e importancia de los estudios citogenéticos en aquellos casos en que el profesional de salud se enfrente a un paciente con una probable enfermedad de causa genética o síndrome dismórfico, además de exponer algunas experiencias de un laboratorio de Citogenética en el Paraguay, donde se realiza el estudio cromosómico. Aún con el advenimiento de la Biología Molecular y de la Citogenética Molecular, la citogenética convencional sigue siendo una herramienta de gran importancia, ya que permite realizar el diagnóstico de una enfermedad genética en pacientes con sospecha clínica de ser portadores de anomalías cromosómicas, y por tanto asesorar a las familias respecto de dicha enfermedad, proveer un pronóstico, riesgo de recurrencia y en casos que se requiera, un tratamiento(AU)

Cytogenetics is the study of chromosomes both in number and structure. The first publications about human cytogenetics were provided towards the end of the 19th century with the publication of Flemming in 1882 of the first figures of human chromosomes from observations under the microscope and only in 1953, Tjio and Levan determined the actual number of human chromosomes per diploid cell (2n = 46). The purpose of this paper is to present the value, current use and importance of cytogenetic studies in those cases in which the health professional faces a patient with a probable disease of genetic causes or dysmorphic syndrome, in addition to exposing some experiences from a Cytogenetics laboratory in Paraguay, where chromosomal study is carried out. Even with the arrival of Molecular Biology and Molecular Cytogenetics, conventional cytogenetics is a tool with a great importance, which allows the genetic disease diagnosis in patients with clinical suspicion of being carriers of chromosomal abnormalities, allowing to advice families about the disease, as well as to provide a prognosis, risk of recurrence and, in cases that requires it, a treatment(AU)

Analysis of chromosomes of embryos derived from translocation carriers during preimplantation genetic diagnosis cycles / 中华医学遗传学杂志

OBJECTIVE@#To explore the effect of chromosomal translocations on the composition of embryonic chromosomes and its mechanism.@*METHODS@#For 52 couples with one partner carrying a chromosomal translocation, results of next generation sequencing of all embryos derived from 61 cycles were divided into different groups based on the type of translocations, gender of the carrier, and maternal age. Effect of parental chromosomal translocations on the composition of embryonic chromosomes of each group was analyzed.@*RESULTS@#A significant difference was found between carriers of reciprocal and Robertsonian translocations in terms of proportion of abnormal embryos and structurally normal chromosomes (63.3% vs. 27.5%, and 1.1% vs. 0.3%, respectively). Compared with male carriers, there was an increase in the rate of abnormalities for female carriers (67.2% vs. 58.3% for reciprocal translocations, and 45.5% vs. 13.8% for Robertsonian translocations). The risk for chromosomal abnormality also increased with the maternal age. No significant difference was found in the proportion of abnormal embryos between carriers divided by involvement of acrocentric chromosomes or terminal chromosomal breakpoints.@*CONCLUSION@#The types of parental translocation, gender of carrier, maternal age, and interchromosomal effect have certain effect on the composition of embryonic chromosomes.

Genomic Profiling of Chronic Myelogenous Leukemia: Basic and Clinical Approach

Chronic myeloid leukemia (CML) is a hematological stem cell cancer driven by BCR-ABL1 fusion protein. We review the previous and recent evidence on the significance of CML in diagnostic and clinic management. The technical monitoring of BCR-ABL1 with quantitative real time-PCR has been used in assessing patient outcome. The cytogenetic mark of CML is Philadelphia chromosome, that is formed by reciprocal chromosomal translocations between human chromosome 9 and 22, t(9:22) (q³⁴:q¹¹). It makes a BCR-ABL1 fusion protein with an anomaly tyrosine kinase activity that promotes the characteristic proliferation of progenitor cells in CML and acute lymphoblastic lymphoma. The targeting of BCR-ABL1 fusion kinase is the first novel paradigm of molecularly targeted curing.

Application and modification of methods for chromosome culture, preparation and analysis / 中华医学遗传学杂志

Chromosome analysis has been widely used in clinics including prenatal diagnosis. To obtain high-quality metaphase chromosomes, researchers have attempted to modify the methods for chromosome culture, preparation and analysis. Some large research centers also tried to establish standards for quality control. In this paper, modification of methods for the preparation of chromosomes in the last decade is reviewed.

Chromosomal microarray analysis of 2000 pediatric cases / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To assess the feasibility of chromosomal microarray analysis(CMA) for studying the correlation between birth defects and chromosomal aberrations.</p><p><b>METHODS</b>A total of 2000 patients with birth defects were recruited for the CMA testing.</p><p><b>RESULTS</b>Five hundred twenty two patients (26.1%) were found to have chromosomal abnormalities. These included 24 cases with numerical abnormalities, 11 with mosaicisms, and 11 with uniparental disomies. The remaining 476 cases were of well-known microdeletion or microduplication syndromes. The advantage of CMA over conventional karyotyping was demonstrated in many cases.</p><p><b>CONCLUSION</b>As a powerful tool for patients with birth defects, CMA can produce a higher diagnostic yield compared with conventional karyotyping.</p>

Microdeleción 16p12.2: reporte de un caso clínico y revisión de la literatura / 16p12.2 microdeletion: report of a clinical case and review of the literature

Resumen: en el presente manuscrito se describe el caso clínico de una adolescente con retardo mental y otras manifestaciones clínicas que en conjunto hacen sospechar de una enfermedad de origen genético, la microdeleción 16p12.2. El texto enfatiza en el abordaje diagnóstico adecuado de estos pacientes a través del análisis completo del caso y una revisión de la literatura sobre el tema.

Abstract: in this manuscript it is described the clinical case of an adolescent with mental retardation and other clinical manifestations that together make suspect a disease of genetic origin, 16p12.2 microdeletion. The text emphasizes on proper diagnostic approach of these patients, through the comprehensive analysis of the case and a review of the literature about this issue.

A Study of the Association between Enabled Homolog Gene Polymorphisms and Kawasaki Disease in Korean Children

OBJECTIVE: The etiology of the Kawasaki disease (KD) remains unknown despite of extensive studies but infection, immunity, and genetics were suggested as causes. There have been attempted to link susceptibility to KD to allelic variations to search related gene. The enabled homolog (Enah) gene on the human chromosome 1q42.12 encodes enabled/vasodilator-stimulated phosphoprotein (Ena/VASP). Ena/VASP is a regulator of actin cytoskeleton, exists in cytoplasm, and maintains homeostasis such as immune response, blood vessel preservation, and hemostasis. The aim of this study was to investigate polymorphisms of the Enah gene as a risk factor for KD and coronary artery lesions (CALs) as a complication. METHODS: In the Enah gene region, 15 single nucleotide polymorphisms (SNPs) were selected using human SNP websites (http://www.hapmap.org/, genome build). Three hundred and six healthy controls and 106 KD subjects were recruited. SNP genotyping was performed using the Golden Gate assay on an Illumina BeadStation 500 GX (Illumina Inc., San Diego, CA, USA). Frequencies of allele were obtained and the genetic association between of the Enah gene polymorphisms and susceptibility to KD and CALs was analyzed by SNPstats, Haploview software ver. 4.1 (Broad Institute, Cambridge, MA, USA). Multiple logistic regression analysis with adjustment for gender was performed. RESULTS: One SNP (rs1891000) among total fifteen SNPs was associated with KD. Moreover, we found a significant association between rs487591, rs576861, rs7555139, rs10799319, and the development of CALs in KD patients. CONCLUSION: These results suggest that the polymorphism of Enah gene may be associated with the occurrence of KD and development of CALs as a complication.

Genetics of Prader-Willi syndrome and Prader-Will-Like syndrome

The Prader-Willi syndrome (PWS) is a human imprinting disorder resulting from genomic alterations that inactivate imprinted, paternally expressed genes in human chromosome region 15q11-q13. This genetic condition appears to be a contiguous gene syndrome caused by the loss of at least 2 of a number of genes expressed exclusively from the paternal allele, including SNRPN, MKRN3, MAGEL2, NDN and several snoRNAs, but it is not yet well known which specific genes in this region are associated with this syndrome. Prader-Will-Like syndrome (PWLS) share features of the PWS phenotype and the gene functions disrupted in PWLS are likely to lie in genetic pathways that are important for the development of PWS phenotype. However, the genetic basis of these rare disorders differs and the absence of a correct diagnosis may worsen the prognosis of these individuals due to the endocrine-metabolic malfunctioning associated with the PWS. Therefore, clinicians face a challenge in determining when to request the specific molecular test used to identify patients with classical PWS because the signs and symptoms of PWS are common to other syndromes such as PWLS. This review aims to provide an overview of current knowledge relating to the genetics of PWS and PWLS, with an emphasis on identification of patients that may benefit from further investigation and genetic screening.

Genetics of Prader-Willi syndrome and Prader-Will-Like syndrome

The Prader-Willi syndrome (PWS) is a human imprinting disorder resulting from genomic alterations that inactivate imprinted, paternally expressed genes in human chromosome region 15q11-q13. This genetic condition appears to be a contiguous gene syndrome caused by the loss of at least 2 of a number of genes expressed exclusively from the paternal allele, including SNRPN, MKRN3, MAGEL2, NDN and several snoRNAs, but it is not yet well known which specific genes in this region are associated with this syndrome. Prader-Will-Like syndrome (PWLS) share features of the PWS phenotype and the gene functions disrupted in PWLS are likely to lie in genetic pathways that are important for the development of PWS phenotype. However, the genetic basis of these rare disorders differs and the absence of a correct diagnosis may worsen the prognosis of these individuals due to the endocrine-metabolic malfunctioning associated with the PWS. Therefore, clinicians face a challenge in determining when to request the specific molecular test used to identify patients with classical PWS because the signs and symptoms of PWS are common to other syndromes such as PWLS. This review aims to provide an overview of current knowledge relating to the genetics of PWS and PWLS, with an emphasis on identification of patients that may benefit from further investigation and genetic screening.

Application of whole-genome and high-resolution chromosome microarray analysis for the investigation of fetuses with ultrasound abnormalities / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To assess the value of whole-genome high-resolution chromosome microarray analysis (CMA) for the investigation of fetuses with ultrasound abnormalities.</p><p><b>METHODS</b>Whole genome high-resolution CytoScanHD array from Affymetrix was employed to investigate 651 fetuses with structural abnormalities detected by ultrasound, for whom standard G-banded chromosome analysis has revealed a normal karyotype. The fetuses were divided into a single malformation group (n=264) and a multiple malformations group (n=387). In total there were 130 chorionic villus samples, 192 amniotic fluid samples and 329 cord blood samples. Extraction of fetal DNA and CMA experiment have followed the standard guidelines from the manufacturers. All copy number variations (CNVs) detected by CMA were confirmed by fluorescence in situ hybridization (FISH) or real-time polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>CMA analysis has detected genomic CNVs in 475 (73%) cases. Clinically significant CNVs were found in 11.5% (75/651) of fetuses, including two uniparental disomies (UPD) and two cryptic mosaicisms. Variations of unknown significance (VOUS) was found in 2.0% (13/651) of tested fetuses.</p><p><b>CONCLUSION</b>Above results have suggested that whole-genome and high-resolution CMA is valuable for the analysis of fetuses with structural abnormalities detected by ultrasound, which can increase the detection rate by approximately 11%. CMA using single nucleotide polymorphism (SNP) array has the ability to detect UPD and low-level mosaicisms. Sufficient communication between technicians and genetic counselors, parental testing and comparison the results with in-house and relevant online databases can significantly reduce the rate of VOUS.</p>