Prenatal phenotypic analysis and genetic counseling for 22q11.21 microdeletion and microduplication syndrome / 中华围产医学杂志

Objective:To analyze the prenatal clinical phenotypes and pregnancy outcomes of fetuses with 22q11.21 microdeletion and microduplication syndrome to provide a basis for clinical genetic counseling.Methods:This retrospective study involved the cases diagnosed with 22q11.21 microdeletion or microduplication by chromosomal microarray analysis (CMA) due to abnormal ultrasound findings, advanced maternal age, or high-risk pregnancies indicated by serum screening in the Prenatal Diagnosis Center of the First Affiliated Hospital of Air Force Medical University from January 2015 to January 2022. Clinical phenotypes and pregnancy outcomes of the fetuses were analyzed and described.Results:Among 9 141 cases referred for CMA during the study period, 77 cases (0.8%) were diagnosed as 22q11.21 microdeletion or microduplication, including 62 (80.5%) with 22q11.21 microdeletion and 15 (19.5%) with microduplication. In the 22q11.21 microdeletion cases, 58 had typical deletion, and four had atypical deletions, but all fetuses carried TBX1 gene that was clearly associated with congenital heart disease. The 15 fetuses with 22q11.21 microduplication including 14 in the typical region and one in the atypical region. Forty-eight (77.4%) out of the 62 fetuses with 22q11.21 microdeletion were complicated by congenital heart defects, including 28 with conotruncal defects. Five of the 15 fetuses with 22q11.21 microduplication were complicated by congenital heart defects. The cases were followed up on telephone at three to six months after the expected date of delivery. Among the 62 cases with 22q11.21 microdeletion, 52 terminated pregnancies, five were lost to follow-up, and five were delivered (one died after one month of premature delivery, one was born with anal advancement and growth retardation, and three were followed up without obvious abnormality). Among the 15 cases with 22q11.21 microduplication, four terminated pregnancies, two were lost to follow-up, and nine gave birth (eight were followed up without obvious abnormality, one grew slowly). Conclusions:The application of CMA in the prenatal diagnosis of 22q11.21 microdeletion and microduplication fetuses, and the comprehensive analysis of clinical manifestations and pregnancy outcome combined with ultrasonic diagnosis are of great significance in guiding the treatment and rehabilitation after birth of an affected child. Genetic counseling for cases with 22q11.21 microdeletion and microduplication syndrome should be cautious and consider ultrasound findings.

Prenatal diagnosis and genetic analysis of seven fetuses with 16p12.2 microdeletion or microduplication / 中华围产医学杂志

Objective:To investigate the prenatal ultrasonographic features and diagnosis of 16p12.2 copy number variation (CNV).Methods:This retrospective study recruited seven fetuses with 16p12.2 microdeletion/microduplication in the First Affiliated Hospital of Fujian Medical University from January 2017 to December 2021. Data, including the prenatal diagnostic indications, ultrasound findings, karyotypes, genetic testing and mutation tracing results, pregnancy outcomes, and postnatal follow-up data, were summarized with descriptive statistical analysis.Results:Prenatal ultrasound indicated three fetuses with structural abnormalities, including one case each of multiple malformations, interventricular septal defect, and cleft lip and palate. The other four cases were positive for ultrasonic soft markers involving the heart and kidney. The chromosome karyotypes of the seven fetuses were normal. Single nucleotide polymorphism array (SNP array) results showed that four cases had a 381.7-542.4 kb microdeletion containing three genes ( OTOA, METTL9, and IGSF6) in Online Mendelian Inheritance in Man (OMIM) at 16p12.2 (distal region) and three cases had a 484.0-701.7 kb microdeletion/microduplication containing four OMIM genes ( UQCRC2, CDR2, EEF2K, and POLR3E) at 16p12.2 (proximal region). Five (cases 1, 2, 4, 5, and 6) out of the seven fetuses inherited the variants from their phenotypically normal mother/father, and among them, three (cases 2, 4, and 5) were delivered at term and healthy. Two cases (cases 3 and 7) refused to undergo pedigree verification. Case 3, a full-term infant, underwent ventricular septal defect repair three months after birth, and no abnormality was found at 18 months of age. Conclusions:No specific phenotype presents in fetuses with 16p12.2 microdeletion/microduplication in prenatal diagnosis. OTOA gene is the key gene associated with abnormality in the distal region of 16p12.2. Pedigree analysis is conducive to preventing unnecessary termination of pregnancy.

Genetic analysis of products of conception. Should we abandon classic karyotyping methodology? / Análise genética dos produtos de concepção. Devemos abandonar a metodologia de cariotipagem clássica?

ABSTRACT Objective: To compare the results obtained by the classic and molecular methodology in the analysis of products of conception, the advantages and disadvantages of each method. Methods: Retrospective non-randomized analysis of results obtained from product of conception samples submitted to genetic evaluation, from 2012 to 2017. The evaluations were performed using cytogenetics and/or chromosomal microarray analysis or arrays. Results: Forty samples were analyzed using classic cytogenetics, of which 10% showed no cell growth, 50% had normal results and 40% had abnormalities. Of the 41 cases sent for array analysis it was not possible to obtain results in 7.3%, 39.5% were normal and 60.5% had abnormalities. There was no statistical difference among the results (p=0.89). Most abnormal results were seen till 9 weeks' gestation. The later abnormal miscarriage was seen at 28 weeks' gestation, with karyotype 46,XX,del(15)(q26.2-qter). The results are corroborated by the international literature. Conclusion: Classic cytogenetics and array techniques showed comparable results on the type of alteration observed. Array analysis is preferable to cell culture in delayed abortions, while cytogenetics is more able to show polyploidies. Both have the same growth failure rates when product of conception tissue is not properly collected.

RESUMO Objetivo: Comparar os resultados obtidos pela metodologia clássica e molecular na análise de produtos de concepção, além das vantagens e desvantagens de cada método. Métodos: Análise retrospectiva não randomizada dos resultados obtidos a partir de amostras de produto de concepção submetidas à avaliação genética, de 2012 a 2017. As análises foram realizadas por citogenética clássica e/ou análise cromossômica de microarray ou arrays. Resultados: Quarenta amostras foram analisadas por citogenética, das quais 10% não apresentaram crescimento celular, 50% apresentaram resultados normais, e 40% apresentaram anormalidades. Dos 41 casos encaminhados para análise por array, não foi possível obter resultados em 7,3%, 39,5% eram normais, e 60,5% apresentavam alterações. Não houve diferença estatística entre os resultados (p=0,89). A maioria dos resultados anormais foi observada até a nona semana de gestação. Uma perda fetal mais tardia foi observada na 28ª semana de gestação, com cariótipo 46,XX,del(15)(q26.2-qter). Os números observados corroboraram a literatura mundial. Conclusão: As técnicas de citogenética clássica e análise por array mostraram resultados comparáveis no tipo de alteração observada. O array é preferível à cultura de células em abortos tardios, enquanto a citogenética é mais capaz de mostrar poliploidias. Ambos têm as mesmas taxas de falha de crescimento quando o tecido do produto de concepção não é coletado adequadamente.

Hibridación genómica comparativa: su interpretación y uso como herramienta diagnóstica en retardo mental inespecífico y síndromes de microdeleción/microduplicación / Comparative genomic hybridization: its interpretation and use as a diagnostic tool in nonspecific mental retardation and microdeletion/microduplication syndromes

En Colombia el cariotipo por bandeo es todavía la prueba inicial más usada en el estudio de pacientes con retardo mental o con anomalías congénita múltiples. Sin embargo, las técnicas moleculares, particularmente la hibridación genómica comparativa con microarrays, han permitido identificar un número creciente de síndromes de microduplicación o microdeleción en estos pacientes, de modo que mundialmente esta es hoy en día la tecnología de elección para evaluar alteraciones del número de copias. Se realiza esta revisión de la literatura con el objetivo de brindar al personal médico información actualizada acerca de la interpretación y el papel de la hibridación genómica comparativa con microarrays como herramienta diagnóstica en retardo mental inespecífico, síndromes de microdeleción/ microduplicación y análisis cromosómico prenatal. MÉD.UIS. 2016;29(2):137-44.

In Colombia the banding karyotype is still the initial test used in the study of patients with mental retardation or with multiple congenital anomalies. However, molecular techniques, particularly comparative genomic hybridization with microarray have identified a growing number of microdeletion or microduplication syndromes in these patients, so that globally this is the technology of choice nowaday for evaluating copy number alterations. This literature review is aimed at providing to medical personnel the latest information regarding the interpretation and role of comparative genomic hybridization as a diagnostic tool in nonspecific mental retardation, microdeletion/ microduplication syndromes and prenatal chromosomal analysis. MÉD.UIS. 2016;29(2):137-44.

Current status and prospect of genetic testing for chromosomal microdeletion and microduplication syndromes / 中华检验医学杂志

Chromosomal microdeletion and microduplication syndromes are common genetic diseases.Technologies including fluorescence in situ hybridization , chromosomal microarray , real-time PCR, multiplex ligation-dependent probe amplification and high-throughput sequencing have been used to detect these diseases . The advantages and limitations of these technologies as well as their clinical applications in the detection of chromosomal microdeletion and microduplication syndromes are analyzed . (Chin J Lab Med, 2016, 39:407-409 )

Variações no número de cópias cromossômicas submicroscópicas como causa de baixa estatura de início pré-natal / Submicroscopic chromosomal copy number variants as a cause of prenatal onset short stature

A pesquisa de variações no número de cópias (CNVs; copy number variants) cromossômicas tem revelado o importante papel destas alterações genômicas na diversidade populacional e na etiologia de doenças humanas. O modelo de associação de CNVs a doenças envolve deleções e/ou duplicações individualmente raras, mas com segmentos cromossômicos de tamanhos relevantes. Os pacientes com baixa estatura de início pré-natal constituem um grupo heterogêneo com quadros clínicos complexos frequentemente resultantes de alterações genéticas, que, desde o período intrauterino, perturbam os mecanismos e vias de desenvolvimento e crescimento fetais. Assim sendo, aventamos a hipótese de que CNVs raras possam estar entre as causas genéticas de baixa estatura de início prénatal. Para tanto, nosso estudo visou avaliar a presença de deleções ou duplicações submicroscópicas em um grupo selecionado de pacientes nascidos pequenos para idade gestacional (PIG) com baixa estatura persistente sem causa definida. Foram avaliados 51 pacientes nascidos PIG com baixa estatura persistente após o 4º ano de vida que apresentavam dismorfismos, atraso de desenvolvimento neuropsicomotor (DNPM) ou deficiência intelectual, porém sem caracterizar síndromes conhecidas e com cariótipo normal. Amostras de DNA dos pacientes foram submetidas à hibridização genômica comparativa por microarray (aCGH; array comparative genomic hybridization) baseada em oligonucleotídeos na plataforma 60K. Os achados foram comparados com CNVs descritas em bancos de dados de controles normais. Foram identificadas 18 CNVs, ausentes em controles saudáveis, em 17 dos 51 pacientes (33%). As alterações foram avaliadas para classificação de sua patogenicidade de acordo com os seguintes critérios: 1) padrão de herança e segregação familiar; 2) sobreposição a coordenadas genômicas de síndromes conhecidas; 3) sobreposição a CNVs patogênicas descritas em banco de dados; 4) e conteúdo gênico. Quatro CNVs, encontradas em 3 pacientes, foram...

Analysis of chromosomic copy number variants (CNVs) have demonstrated the important role of these genomic imbalances in population diversity and human disease. The model of CNV disease association involves deletions and/or duplications that are individually rare but encompass chromosomal segments of relevant size. Prenatal onset short stature patients constitute a complex group characterized by clinical heterogeneity. The causes of prenatal growth impairment frequently involve genetic changes that disturb the mechanisms and the pathways of fetal growth and development. Thus, we hipothesized that rare CNVs might contribute to the genetic etiology of prenatal onset short stature. In order to evaluate this assumption, our study analyzed the presence of submicroscopic deletions and/or duplications in a selected group of patients born small for gestational age with persistent short stature but without a recognized cause. A total of 51 patients with prenatal and postnatal growth retardation associated with dysmorphic features, developmental delay and/or intellectual disability, but without criteria for known syndromes, were selected. All patients had normal G-banded karyotyping. Array-based comparative genomic hybridization (aCGH) in a whole-genome 60K platform was performed using DNA obtained from all patients. Detected CNVs were compared with CNV data from healthy controls individuals, excluding common copy number polymorphisms. In 17 of the 51 patients screened (33%), 18 rare CNVs were identified. The pathogenicity of CNVs was assessed by considering the following criteria: inheritance and familial segregation; overlap with genomic coordinates for a known genomic imbalance syndrome; overlap with CNVs previously identified in other patients with prenatal onset short stature; and gene content. Four distinct CNVs, found in three patients, were classified as pathogenic: 1) del 22q11.21; 2) dup 10q26.2-26.3 and del 10q26.3; and 3) del 4q28.2-q31.21. Five CNVs, found...