Fenotipos inesperados en el síndrome de Alport: la necesidad del estudio genético / Unexpected phenotypes in Alport syndrome: the need for genetic testing

El diagnóstico del síndrome de Alport supone un reto en la edadpediátrica, debido a la ausencia de fenotipos clínicos esperados de la enfermedad, su clásica caracterización de entidad rara y la práctica muy restringida de biopsias renales con análisis rutinario de la muestra por microscopía electrónica durante la infancia. Se presentan las características clínicas y genéticas de 6 pacientes pediátricos (4 mujeres) diagnosticados de síndromede Alport en dos centros hospitalarios entre 2018 y 2021. Todos los pacientes presentaron un debut clínico claramente diferente y ninguno presentó complicaciones auditivas nioftalmológicas. La mitad carecía de antecedentes familiares de enfermedad renal crónica. Ninguna biopsia renal realizada confirmó el diagnóstico. Todos los pacientes fueron confirmadosgenéticamente y fueron el caso índice del estudio familiar. Esta serie ilustra la presencia de fenotipos clínicos inesperados en el síndrome de Alport y refleja la necesidad de incorporar el estudio genético para su diagnóstico.

The diagnosis of Alport syndrome is a challenge in the pediatric age, due to the absence of expected clinical phenotypes of the disease, its classic characterization of a rare disease and the very restricted practice of renal biopsies with routine analysis of the sample by electron microscopy during infancy. The clinical and genetic characteristics of 6 pediatric patients (4 women) diagnosed with Alport syndrome in two hospital centers between 2018 and 2021 are reported. All patients presented a clearly different clinical debut and none presented auditory or ophthalmological complications. Half had no family history of chronic kidney disease. No kidney biopsy performed confirmed the diagnosis. All patients were genetically confirmed and were the index case in the family study. This series illustrates the presence of unexpected clinical phenotypes in Alport syndrome and reflects the need for the incorporation of the genetic study for its diagnosis.

Tamizaje para cáncer de mama con resonancia magnética en mujeres portadoras de mutaciones BRCA y no-BRCA / Magnetic resonance imaging breast cancer screening in women who are carriers of BRCA and non-BRCA gene mutations / Rastreamento de câncer de mama com ressonância magnética em mulheres com mutações BRCA e não BRCA

Introducción: la predisposición hereditaria causada por mutaciones patogénicas de la línea germinal (MPG) explica hasta el 10% de los cánceres de mama. Para reducir su impacto en mujeres mutadas se han propuesto diferentes estrategias, tales como las cirugías reductoras de riesgo o el screening con resonancia magnética (RM) de mamas. Métodos: en este estudio observacional retrospectivo se analizaron los registros de mujeres portadoras de MPG para evaluar las diferentes acciones tomadas luego del test genético. A las pacientes no mastectomizadas se les recomendó ingresar a un programa anual de cribado con RM y se evaluó el porcentaje de adherencia al plan, el número de biopsias efectuadas y el número de cánceres de mama detectados. Resultados: se incluyeron 134 mujeres con MPG, con una distribución en tercios iguales de los genes BRCA1, BRCA2 y genes no-BRCA. Entre las mutadas con indicación de seguimiento, 64% ingresaron al programa de cribado con RM. Las razones que llevaron a las mujeres a no ingresar al programa de seguimiento fueron: la oposición del médico tratante (53%), oposición de la paciente (38%), y falta de recursos (9%). Se realizaron seis biopsias por hallazgos en la RM entre las cuales se detectó un cáncer de mama. La incidencia de cáncer fue de 11 cada 1.000 mujeres-años de riesgo. Conclusiones: nuestro programa de seguimiento con RM de pacientes mutadas logró captar un porcentaje alto de candidatas. Una proporción significativa de las mujeres no ingresó debido la desaprobación del médico tratante o de la propia paciente. La evidencia obtenida revela una necesidad imperiosa de reforzar los programas educativos que destaquen la importancia del seguimiento con RM de las pacientes de alto riesgo en nuestro país.

Summary: Introduction: genetic propensity caused by germline pathogenic mutations explain up to 10% of breast cancer cases. Different strategies have been proposed to reduce its impact on women who are carriers of mutations, such as risk-reducing surgeries or breast magnetic resonance screening. Method: observational, retrospective study analyzing the medical records of women who are carriers of germline pathogenic mutations to assess the different measures taken after the genetic test. Non-mastectomized patients were advised to join an annual MRI screening program and the percentage of adherence to plan was evaluated, along with biopsies performed and the number of breast cancer cases detected. Results: 134 women carriers of germline pathogenic mutations were included in the study, with equal distributions in thirds for BRCA1, BRCA2 and non-BRCA genes. 64% of carriers of mutations who were subject to follow-up checkups joined the RMI screening program. The reasons why women failed to join the follow-up program were: the treating physician objected to the program (53%), the patients opposed to program (38%) and lack of resources (9%). Six biopsies were performed as a consequence of findings in the RMI, and one case of breast cancer was detected. Cancer incidence was 11 out of 1000 women - risk years. Conclusions: our RMI follow-up program for women who are carriers of mutations managed to attract a high percentage of candidates. A significant amount of women failed to join the program because of their treating physician's or their own disapproval. Evidence obtained reveals the dramatic need to reinforce educational programs that emphasize on the importance of RMI follow-up of high risk patients in our country.

Introdução: a predisposição hereditária causada por mutações germinativas patogênicas (GMP) explica até 10% dos cânceres de mama. Para reduzir seu impacto em mulheres com mutações, diferentes estratégias têm sido propostas, como cirurgias de redução de risco ou ressonância magnética (RM) das mamas. Métodos: neste estudo observacional retrospectivo, os registros de mulheres portadoras de MPG foram analisados para avaliar as diferentes ações tomadas após o teste genético. Pacientes não mastectomizadas foram recomendadas a entrar em um programa anual de triagem por ressonância magnética e foram avaliados o percentual de adesão ao plano, o número de biópsias realizadas e o número de cânceres de mama detectados. Resultados: foram incluídas 134 mulheres com MPG, com uma distribuição de terços iguais dos genes BRCA1, BRCA2 e não-BRCA. Entre as mulheres com mutações com indicação de acompanhamento, 64% entraram no programa de triagem por ressonância magnética. Os motivos que levaram as mulheres a não ingressarem ao programa de acompanhamento foram: oposição do médico assistente (53%), oposição da paciente (38%) e falta de recursos (9%). Seis biópsias foram realizadas devido a achados de ressonância magnética, entre os quais foi detectado um câncer de mama. A incidência de câncer foi de 11 por 1.000 mulheres-ano de risco. Conclusões: nosso programa de acompanhamento de ressonância magnética para pacientes com mutação conseguiu capturar uma alta porcentagem de candidatas. Uma proporção significativa de mulheres não entrou devido à falta de aprovação do médico assistente ou da própria paciente. As evidências obtidas revelam a necessidade urgente de reforçar programas educacionais que destaquem a importância do acompanhamento por RM de pacientes de alto risco no Uruguai.

Implicações éticas dos testes genéticos de suscetibilidade ao câncer de mama / Ethical implications of genetic testing of susceptibility to breast cancer / Implicaciones éticas de las pruebas genéticas de susceptibilidad al cáncer de mama

Resumo O câncer de mama representa um problema de saúde pública por ser a neoplasia maligna de maior incidência em mulheres no mundo. A forma hereditária corresponde a cerca de 5% a 10% de todos os casos e está diretamente relacionada à herança de mutações genéticas, sendo as principais nos genes supressores de tumor BRCA1 e BRCA2. A identificação dessas mutações é de extrema importância pelo elevado risco de desenvolvimento de câncer de mama nessa população, permitindo estratégias de rastreamento diferenciado e adoção de medidas de redução de risco. Entretanto, é importante e necessário refletir sobre os aspectos éticos relacionados ao uso indiscriminado de testes genéticos. O objetivo deste trabalho foi avaliar o conhecimento e a opinião de médicos de um centro de referência oncológico sobre a indicação dos testes genéticos de suscetibilidade ao câncer de mama mediante dilemas éticos aos quais são submetidos na prática médica.

Abstract Breast cancer is a public health problem because it is the malignant neoplasm with the highest incidence in women worldwide. The hereditary form corresponds to about 5% to 10% of all cases and is directly related to the inheritance of genetic mutations. The main ones occur in the BRCA1 and BRCA2 tumor suppressor genes. The identification of these mutations is extremely important because of the high risk of breast cancer development in this population, allowing differentiated screening strategies and the adoption of risk reduction measures. However, reflections on the ethical aspects related to the indiscriminate use of genetic testing are important and necessary. The objective of this study was to evaluate the knowledge and opinion of physicians of an oncology reference center on the indication of genetic tests for susceptibility to breast cancer given the ethical dilemmas to which they are submitted in medical practice.

Resumen El cáncer de mama representa un problema de salud pública, ya que es la neoplasia maligna con mayor incidencia en las mujeres de todo el mundo. La forma hereditaria corresponde a entre el 5% y el 10% de todos los casos y está directamente relacionada con la herencia de mutaciones genéticas, y las principales se dan en los genes supresores de tumores BRCA1 y BRCA2. La identificación de estas mutaciones es extremadamente importante debido al elevado riesgo de esta población de desarrollar cáncer de mama, además de permitir estrategias de rastreo diferenciadas y la adopción de medidas de reducción del riesgo. Sin embargo, es importante y necesario reflexionar sobre los aspectos éticos relacionados con el uso indiscriminado de las pruebas genéticas. El objetivo de este estudio fue evaluar el conocimiento y la opinión de los médicos de un centro oncológico de referencia sobre la indicación de las pruebas genéticas de susceptibilidad al cáncer de mama mediante los dilemas éticos a los que se ven sometidos en la práctica médica.

Nefronoptisis: reporte de un caso pediátrico / Nephronophthisis: a pediatric case report

La nefronoptisis es una enfermedad renal quística, de herencia autosómica recesiva, causada por mutaciones en genes que codifican proteínas involucradas en la función de cilios primarios, lo que resulta en enfermedad renal y manifestaciones extrarrenales como degeneración retiniana y fibrosis hepática. Según la edad de desarrollo de enfermedad renal crónica terminal, se describen tres formas clínicas de presentación: infantil, juvenil y adolescente. El diagnóstico se realiza por una prueba genética positiva o una biopsia de riñón que demuestre cambios tubulointersticiales crónicos con un engrosamiento de las membranas basales tubulares. No existe hasta la actualidad una terapia curativa, por lo que el trasplante renal oportuno es determinante en cuanto al pronóstico. Se presenta un paciente de 13 meses de edad con poliuria de 3 meses de evolución, insuficiencia renal, anemia y elevación de transaminasas. Con hallazgos histológicos compatibles en la biopsia renal, se arribó al diagnóstico de nefronoptisis infantil, con afectación hepática

Nephronophthisis is an autosomal recessive cystic kidney disease caused by mutations in genes that encode proteins involved in the primary cilia function, resulting in kidney disease and extrarenal manifestations such as retinal degeneration and liver fibrosis. According to the age of development of end-stage chronic kidney disease, three clinical forms of presentation are described: infantile, juvenile and adolescent. Diagnosis is made by a positive genetic test, or a kidney biopsy demonstrating chronic tubulointerstitial changes with thickening of the tubular basement membranes. At the moment there is no healing therapy, so early kidney transplant is a fundamental tool to improve prognosis.We present a 13-month old male patient with polyuria, kidney failure, anemia and elevated aminotransferases over three months. With compatible histological kidney biopsy, the diagnosis of infantile nephronophthisis with liver involvement was reached.

Congenital myasthenic syndrome in a cohort of patients with 'double' seronegative myasthenia gravis / Síndrome miastênica congênita em uma série de pacientes com miastenia gravis duplo soronegativa

ABSTRACT Background: Congenital myasthenic syndromes (CMS) have some phenotypic overlap with seronegative myasthenia gravis (SNMG). Objective: The aim of this single center study was to assess the minimum occurrence of CMS misdiagnosed as double SNMG in a Brazilian cohort. Methods: The genetic analysis of the most common mutations in CHRNE, RAPSN, and DOK7 genes was used as the main screening tool. Results: We performed genetic analysis in 22 patients with a previous diagnosis of 'double' SNMG. In this study, one CMS patient was confirmed due to the presence of compound heterozygous variants in the CHRNE gene (c.130insG/p.Cys210Phe). Conclusions: This study confirmed that CMS due to CHNRE mutations can be mistaken for SNMG. In addition, our study estimated the prevalence of misdiagnosed CMS to be 4.5% in 'double' SNMG patients of our center. Based on our findings, genetic screening could be helpful in the diagnostic workup of patients with 'double' SNMG in whom differential diagnosis is recommended.

RESUMO Antecedentes: As síndromes miastênicas congênitas (SMC) podem ter sobreposição fenotípica com a miastenia gravis soronegativa (MG-SN). Objetivo: Estabelecer a prevalência mínima de SMC diagnosticada inicialmente como MG duplo soronegativa em uma série de casos brasileiros. Métodos: A análise genética das mutações mais comuns nos genes CHRNE, RAPSN e DOK7 foi usada como o principal exame de triagem. Resultados: Vinte e dois pacientes com diagnóstico prévio de MG-SN foram geneticamente analisados, sendo que uma paciente foi confirmada com SMC devido a presença de variante em heterozigose composta no gene CHRNE (c.130insG/p.Cys210Phe). Conclusões: O presente estudo confirma que SMC devido mutação no gene CHNRE pode ser inicialmente diagnosticada como MG-SN. O estudo estimou como 4,5% a prevalência de diagnóstico de SMC entre nossos pacientes préviamente diagnosticados como MG-SN. Com base nesse estudo, a análise genética pode ser recomendada para investigação do diagnóstico diferencial em pacientes com MG-SN.

Investigação de causas genéticas associadas ao desenvolvimento de sarcomas em idade jovem / Investigation of genetic causes associated with the development of sarcomas at young age

Os avanços recentes na genômica permitiram o reconhecimento de quase uma centena de novos genes de predisposição ao câncer (GPC). Embora o rastreamento genético de uma parte destes genes esteja atualmente bem estabelecido para os tumores hereditários mais comuns, há uma série de tumores raros, como sarcomas, que podem estar associados a síndromes de câncer hereditário, mas cuja relação genótipo-fenótipo ainda é desconhecida. Dessa forma, o presente estudo propôs-se a: definir a frequência de variantes raras germinativas patogênicas em GPCs em crianças, adolescentes e adultos jovens com sarcomas; avaliar as características moleculares dos tumores para confirmar sua causa genética em casos selecionados, realizando análise de perda de heterozigose (LOH); identificar novos genes e vias relevantes associados ao desenvolvimento de condrossarcomas e sarcomas ultrarraros. Para isso, foram rastreadas variantes germinativas em 177 pacientes jovens diagnosticados com sarcoma abaixo de 40 anos, através da análise de sequenciamento de nova geração, com painéis customizados de 113/126 GPCs. Primeiramente, foi rastreada a variante fundadora do gene TP53 mais prevalente na população brasileira (p.Arg337His) e 5/177 pacientes foram detectados como portadores e excluídos da análise de painel. No painel, foram avaliados 172 pacientes e em 33 foram detectadas variantes patogênicas (P) ou provavelmente patogênicas (PP) (18,6%), sendo estas em genes previamente associados ao risco no desenvolvimento de sarcomas, como CHEK2, EXT1, EXT2, NF1, RB1 e TP53, mas também em genes no qual esse risco ainda é desconhecido (AKT1, ERCC3, ERCC4, FANCM, MITF, MUTYH, NTHL1, SLX4 e TSC2) ou é emergente (BRCA2, ERCC2, PALB2). Cento e trinta e nove (78,5%) pacientes tiveram variantes de significado incerto ou foram negativos. Portadores de variantes P/PP foram mais propensos a apresentar mais de um tumor primário do que não portadores (21,1% X 6,5%; p=0,012). Dos 25 tumores avaliados para LOH, a perda do alelo selvagem foi detectada em nove (36%), sendo um dos genes de associação desconhecida a sarcomas (MITF). Para explorar novos genes candidatos, 9 pacientes com condrossarcomas ou sarcomas ultrarraros negativos para variantes P/PP foram incluídos em análise de sequenciamento de exoma tumoral e germinativo. Foram priorizadas na análise germinativa variantes em 10 GPCs conhecidos e 22 genes com variantes de perda de função e missenses em que a relação com câncer hereditário é desconhecida. Foi encontrada somente uma variante em um gene associado a sarcomas (RECQL4) e em um gene emergente (BRCA2). Uma variante patogênica no gene RAD50 foi detectada em um paciente com sarcoma fibromixóide. Em dois tumores distintos, foi observada alteração no gene COL7A1. Na análise somática, em três genes (TP53, PTCH1, CREBBP) foram encontradas alterações potencialmente significantes clinicamente, visto que são genes de associação conhecida a sarcomas. Também foram identificados outros genes mutados, alguns deles incluídos em vias biológicas que podem ser interessantes para sarcomas, como VPS16 e MYF6. Contudo, para que seja possível realizar associações genótipofenótipo dos dados de exoma, tanto germinativo quanto somático, outras evidências são necessárias, como análise de transcriptoma e co-segregação. Com os dados do painel, nossos resultados destacam uma alta taxa de variantes P/PP em GPCs em pacientes jovens brasileiros com sarcoma (21,5% incluindo os pacientes portadores da variante TP53 p.Arg337His), mesmo em pacientes sem história familiar de câncer. As taxas de variantes P/PP variaram de 0% a 33% entre os subtipos de sarcoma e exibiram associações específicas entre subtipos e genes. Isso aponta a urgência de implementar estratégias de triagem genética adequadas para esses indivíduos e suas famílias.

Recent advances in genomics have allowed the recognition of nearly a hundred new cancer predisposing genes (CPGs). Although genetic screening in some of these genes is currently well established for the most common hereditary tumors, there are a number of rare tumors, such as sarcomas, that may be associated with hereditary cancer syndromes, but whose genotypephenotype relationship is still unknown. Thus, the present study aimed to: define the frequency of rare pathogenic germline variants in CPGs in children, adolescents and young adults with sarcomas; assess the molecular characteristics of tumors to confirm their genetic cause in selected cases, performing loss of heterozygosity (LOH) analysis; identify novel genes and relevant pathways associated with the development of chondrosarcomas and ultra-rare sarcomas. For this, we searched for germline variants in 177 young patients diagnosed with sarcoma under 40 years old, through next-generation sequencing analysis, with customized panels of 113/126 CPGs. First, we searched for the founder variant in TP53 gene (p.Arg337His) - most prevalent in the Brazilian population - and found that 5/177 patients were detected as carriers, being excluded from the panel analysis. In the panel, 172 patients were evaluated and in 33 (18.6%) there were detected germline pathogenic variants (GPVs), occurring in genes previously associated with the risk of developing sarcomas (TP53, RB1, NF1, CHEK2, EXT1 and EXT2), but also in genes where that risk is still unknown (ERCC2/3, TSC2, RAD50, FANCM, and others) or is emerging (PALB2, BRCA2). GPVs carriers were more likely to present more than one primary tumor than non-carriers (21.1% X 6.5%; p=0.012). One hundred and thirty-nine (78.5%) patients had variants of uncertain significance or were negative. Of the 25 tumors evaluated for LOH, loss of the wild-type allele was detected in nine (36%), in which one of the genes has an unknown association with sarcomas (MITF). To explore new candidate genes, 9 patients with chondrosarcomas or ultra-rare sarcomas negative for GPVs were included in tumor exome and germline sequencing analysis. In the germline analysis, there were prioritized variants in 10 known CPGs and 22 genes with loss-of-function and missense variants in which the relationship with hereditary cancer is unknown. Only one variant was found in a sarcoma-associated gene (RECQL4) and in an emergent gene (BRCA2). A pathogenic variant in the RAD50 gene was detected in a patient with fibromyxoid sarcoma. An alteration in COL7A1 gene was observed in two different tumors. In the somatic analysis, there were found potentially clinically significant alterations in three genes (TP53, PTCH1, CREBBP), since they are genes with a known association with sarcomas. Other mutated genes were also identified, some of them included in biological pathways that may be interesting for sarcomas, such as VPS16 and MYF6. However, in order to be able to perform genotype-phenotype associations of exome data, other evidences are needed for both germline and somatic evaluation, such as transcriptome analysis and co-segregation. With panel data, our results highlight a high rate of GPVsin CPGs in young Brazilian patients with sarcoma (21.5% including patients carrying the TP53:p.Arg337His variant), even in patients with no family history of cancer. Our findings reveal that 1 in each 5 patients with sarcomas under 40 years old presented a GPV, even in patients without family history of cancer. GPVs rates varied from 0% to 33% across sarcoma subtypes and exhibited specific gene-subtypes associations. This pinpoints the urgency of implementing appropriated genetic screening strategies for these individuals and their families.

Practical tips to using formalin-fixed paraffin-embedded tissue archives for molecular diagnostics in a South African setting

Background: Formalin-fixed paraffin-embedded (FFPE) tissue archives in hospitals, biobanks, and others offer a vast collection of extensive, readily available specimens for molecular testing. Unfortunately, the use of tissue samples for molecular diagnostic applications is challenging; thus, the forensic pathology FFPE tissue archives in Africa have been a largely unexploited genetic resource, with the usability of DNA obtainable from these samples being unknown.Intervention: The study, conducted from January 2015 to August 2016, determined the usefulness of FFPE tissue as a reliable source of genetic material for successful post-mortem molecular applications and diagnostics. Formalin-fixed paraffin-embedded tissue samples were collected and archived from autopsies conducted over 13 years in the forensic medicine department of the University of Pretoria (Pretoria, South Africa). Deoxyribonucleic acid from FFPE tissue samples and control blood samples was amplified by high-resolution melt real-time polymerase chain reaction before sequencing. The procurement parameters and fixation times were compared with the quantity and quality of the extracted DNA and the efficiency of its subsequent molecular applications.Lessons learnt: This study has shown that FFPE samples are still usable in molecular forensics, despite inadequate sample preparation, and offer immense value to forensic molecular diagnostics.Recommendations: FFPE samples fixed in formalin for more than 24 h should still be used in molecular diagnostics or research, as long as the primer design targets amplicons not exceeding 300 base pairs.

Facteurs prédictifs de la surdité professionnelle induite par le bruit chez les travailleurs des centrales électriques / Predictive factors of occupational noise-induced hearing loss in power plant workers

Analyser le lien entre la surdité professionnelle induite par le bruit et les caractéristiques socioprofessionnelles des travailleurs. Méthodes: C'était une étude prospective et analytique, par enquête avec évaluation audiométrique du 1er août au 30 septembre 2020, concernant 92 travailleurs des deux centrales de la Société Nationale d'Electricité de N'Djamena.Les tests de khi2et de corrélation de Pearson étaient utilisés à la recherche d'un lien entre la surdité due au bruit et les facteurs socioprofessionnels; une différence était dite statistiquement significative si p <0,05. Résultats: L'échantillon était constitué de 96% d'hommes. L'âge variait de 23 à 64 ans avec une moyenne de 38,7 ± 9,0 ans. Quarante-sept (51%) employés étaient formés sur la sécurité en milieu professionnel. Les agents de quarts représentaient 45% des cas (n=41). La durée d'exposition moyenne au bruit était de 10,8 ± 8,5 ans. Le port des équipements de protection individuelle était régulier dans 86% des cas (n =79). La surdité professionnelle a été observée dans 55% des cas (n=51). L'âge (p <10-3) et la durée d'exposition au bruit (p=0,002) étaient les facteurs associés significativement à la surdité. Conclusion: L'âge et l'ancienneté sont les facteurs prédictifs de la surdité chez les travailleurs exposés aux bruits des centrales électriques de N'Djamena.

Clinical features and genetic analysis of a Chinese pedigree affected with X-linked adrenoleukodystrophy / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical features and variants of ABCD1 gene in a Chinese pedigree affected with X-linked adrenoleukodystrophy.@*METHODS@#Clinical data of the proband were collected and analyzed. Potential variant of the ABCD1 gene were analyzed by PCR and Sanger sequencing of the proband, his parents and 100 unrelated healthy individuals.@*RESULTS@#The prominent features of the proband included cerebellar and brainstem lesions, along with increased serum level of very-long chain fatty acids. He was found to harbor a hemizygous c.1509delG (p.L504Sfs*54) variant of the ABCD1 gene, for which his mother was heterozygous. The same variant was not detected in his father and 100 healthy controls.@*CONCLUSION@#X-linked adrenoleukodystrophy has a variety of clinical manifestations. Discovery of the c.1509delG (p.L504Sfs*54), as a novel pathogenic variant of the ABCD1 gene, has enabled diagnosis and genetic counseling for this pedigree.

Clinical features and genetic analysis of a case with Perlman syndrome due to variant of DIS3L2 gene / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical phenotype and genetic characteristics of a child with Perlman syndrome.@*METHODS@#Genomic DNA was extracted from peripheral blood samples from the patient and her parents. Whole exome sequencing (WES) was carried out to detect potential variant in the proband. Candidate variant was verified by Sanger sequencing. The pathogenicity of candidate variants was evaluated according to the guidelines of the American College of Medical Genetics and Genomics (ACMG).@*RESULTS@#The results of WES showed that the proband has harbored compound heterozygous variants of the DIS3L2 gene, namely c.2109delC and c.1829.c.1830insC, which were respectively inherited from her mother and father. The results were confirmed by Sanger sequencing. Based on the ACMG guidelines, the two novel variants were both predicted to be pathogenic (PVS1+PS2+PM2).@*CONCLUSION@#The compound heterozygous variants of the DIS3L2 gene probably underlay the Perlman syndrome in this patient. Above finding has enriched the spectrum of DIS3L2 gene mutations.

Clinical characteristics and genetic analysis of a Chinese pedigree affected with mitochondrial DNA depletion syndrome due to compound heterozygous variants of RRM2B gene / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical characteristics and pathogenic gene in a Chinese pedigree affected with mitochondrial DNA depletion syndrome 8A (MTDPS8A).@*METHODS@#Whole exome sequencing was carried out for the patient. Sanger sequencing was used to verify the results, and PolyPhen-2 and PROVEAN software were used to predict the impact of amino acid changes on the function of the protein.@*RESULTS@#The patient, a two-month-old female, was admitted to the hospital for poor milk intake and poor mental response. Her clinical manifestations included feeding difficulty, shortness of breath and low muscle tone. Auxiliary laboratory test indicated that the infant was underdeveloped with abnormal liver, kidney, and heart functions accompanied by hyperlacticacidemia. She responded poorly to treatment and eventually died. Sequencing revealed that the child has carried compound heterozygous missense variants of the RRM2B gene, namely c.16delA (p.R6Gfs*22) and c.175G>C (p.A59P), which were respectively inherited from her father and mother, and both were newly discovered pathologic variants.@*CONCLUSION@#The c.16delA and c.175G>C compound heterozygous variants of the RRM2B gene probably underlay the pathogenesis of MTDPS8A. Above finding has strengthened the understanding of the clinical feature and genetic etiology of this disease and expanded the mutation spectrum of the RRM2B gene.

Identification of pathogenic variant and preimplantation genetic testing for a Chinese family affected with osteogenesis imperfecta / 中华医学遗传学杂志

OBJECTIVE@#To identify the pathogenic variant for a husband with osteogenesis imperfecta and provide preimplantation genetic testing (PGT) for the couple.@*METHODS@#High-throughput sequencing and Sanger sequencing were carried out to identify the pathologic variant in the husband patients. PGT of embryos was performed through direct detection of the mutation site. Meanwhile, chromosome aneuploidy of the blastocysts was screened. Following transplantation, cytogenetic and genetic testing of fetal amniotic fluid sample was carried out during mid-pregnancy. Chromosome copy number variant (CNV) was detected at multiple sites of the placenta after delivery.@*RESULTS@#The husband was found to harbor heterozygous c.544-2A>G variant of the COL1A1 gene. The same variant was not detected in either of his parents. PGT revealed that out of three embryos of the couple, one was wild-type for the c.544-2A site but mosaicism for duplication of 16p13.3.11.2. The other two embryos were both heterozygous for the c.544-2A>G variant. Following adequate genetic counseling, the wild-type embryo was transplanted. Amniotic fluid testing confirmed that the fetus had normal chromosomes and did not carry the c.544-2A>G variant. The copy number of chromosomes at different parts of placenta was normal after birth.@*CONCLUSION@#For couples affected with monogenic disorders, e.g., osteogenesis imperfecta, direct detection of the mutation site may be used for PGT after identifying the pathogenic variant. After adequate genetic counseling, prenatal diagnosis must be carried out to ensure the result.

Standards for the interpretation of constitutional copy number gain: Recommendation from the American College of Medical Genetics and Genomics (ACMG) and Clinical Genome Resource (ClinGen) / 中华医学遗传学杂志

Copy number variants (CNVs) are common causes of human genetic diseases. CNVs detection has become a routine component of genetic testing, especially for pediatric neurodevelopmental disorders, multiple congenital abnormalities, prenatal evaluation of fetuses with structural anomalies detected by ultrasound. Although the technologies for CNVs detection are continuously improving, the interpretation is still challenging, with significant discordance across different laboratories. In 2020, the American College of Medical Genetics and Genomics (ACMG) and the Clinical Genome Resource (ClinGen) developed a guideline for the interpreting and reporting of constitutional copy number variants, which introduced a quantitative, evidence-based scoring framework. Here, we detailed the key points of interpreting the copy number gain based on the guideline, used six examples of different categories to illuminate the scoring process and principles. We encourage a professional understanding and application of this guideline for the detected copy number gains in China in order to further improve the clinical evaluation accuracy and consistency across different laboratories.

The clinical phenotype and gene analysis of syndromic deafness with PTPN11 gene mutation / 中华耳鼻咽喉头颈外科杂志

Objective: To analyze the clinical phenotype and screen the genetic mutations of hereditary deafness in three deaf families to clarify their molecular biology etiology. Methods: From January 2019 to January 2020, three deaf children and family members were collected for medical history, physical examination, audiology evaluation, electrocardiogram and cardiac color Doppler ultrasound, temporal bone CT examination, and peripheral blood DNA was obtained for high-throughput sequencing of deafness genes. Sanger sequencing was performed to verify the variant sites among family members. The pathogenicity of the variants was evaluated according to the American College of Medical Genetics and Genomics. Results: The probands in the three families had deafness phenotypes. In family 1, proband had multiple lentigines, special facial features, growth retardation, pectus carinatum, abnormal skin elasticity, cryptorchidism and other manifestations. In family 2, proband had special facial features, growth retardation and abnormal heart, and the proband in family 3 had growth retardation and abnormal electrocardiogram. Genetic testing of three families detected three heterozygous mutations in the PTPN11 gene: c.1391G>C (p.Gly464Ala), c.1510A>G (p.Met504Val), c.1502G>A (p.Arg501Lys). All three sites were missense mutations, and the mutation sites were highly conserved among multiple homologous species. Based on clinical manifestations and genetic test results, proband 1 was diagnosed with multiple lentigines Noonan syndrome, and probands 2 and 3 were diagnosed with Noonan syndrome. Conclusion: Missense mutations in the PTPN11 gene may be the cause of the disease in the three deaf families. This study enriches the clinical phenotype and mutation spectrum of the PTPN11 gene in the Chinese population.

Consensus of Chinese experts on hot issues in genetic testing of advanced breast cancer (2021 edition) / 中华肿瘤杂志

Advanced breast cancer is a complicated disease with poor prognosis, which is difficult for salvage treatment. Although advanced breast cancer is difficult to cure at present, we can improve the life quality and prolong survival time of patients by applying optimized treatment. In recent years, with the rapid development of molecular biology and gene testing technology, studies on advanced breast cancer continue to deepen. Gene targeted therapy significantly extends the survival time of patients with advanced breast cancer. Gene testing is one of the important means for molecular typing, genetic diagnosis, therapeutic monitoring, drug resistance, and treatment choice of breast cancer, which is of great significance for the selection of targeted drugs and the management plan. In this consensus, the Expert Committee summarized ten hot issues of gene testing for advanced breast cancer and discussed the applicable population, clinical significance, and the application of molecular markers circulating tumor DNA (ctDNA), whole exome sequencing (WES) in different molecular types, and the standardization of next generation sequencing (NGS) technology applied in clinic. This consensus aimed to guide clinicians how to rationally apply the gene testing to know more comprehensive genetic testing information, and formulate more precise treatment strategies for patients with advanced breast cancer.

Genetic testing and analysis of 2 cases of trisomy 11 mosaicism / 南方医科大学学报

Trisomy 11 mosaicism is clinically rare, for which making diagnostic and treatment decisions can be challenging. In this study, we used noninvasive prenatal testing, chromosome karyotype analysis, chromosome microarray analysis, copy number variation sequencing and fluorescence in situ hybridization for detecting trisomy 11 mosaicism in two cases and provided them with genetic counseling. In one of the cases, the fetus with confined placental mosaicism trisomy 11 presented with severe growth restriction and a placental mosaic level of 44%, and pregnancy was terminated at 25+3 weeks of gestation. In the other case with true low-level fetal mosaicism of trisomy 11, the pregnancy continued after exclusion of the possibility of uniparental disomy and structural abnormalities and careful prenatal counseling. The newborn was followed up for more than one year, and no abnormality was found. Noninvasive prenatal testing is capable of detecting chromosomal mosaicism but may cause missed diagnosis of true fetal mosaicism. For cases with positive noninvasive prenatal testing but a normal karyotype of the fetus, care should be taken in prenatal counseling and pregnancy management.

Clinical manifestations and gene analysis of 18 cases of hereditary protein S deficiency / 中华血液学杂志

Objective: To analyze the clinical manifestations and molecular pathogenesis of 18 patients with inherited protein S (PS) deficiency. Methods: Eighteen patients with inherited PS deficiency who were admitted to the Institute of Hematology & Blood Diseases Hospital from June 2016 to February 2019 were analyzed: activity of protein C (PC) and antithrombin (AT) , PS activity were measured for phenotype diagnosis; high throughput sequencing (HTS) was used for screening of coagulation disease-related genes; Sanger sequencing was used to confirm candidate variants; Swiss-model was used for three-dimensional structure analysis. Results: The PS:C of 18 patients ranged from 12.5 to 48.2 U/dL. Among them, 16 cases developed deep vein thrombosis, including 2 cases each with mesenteric vein thrombosis and cerebral infarction, and 1 case each with pulmonary embolism and deep vein thrombosis during pregnancy. A total of 16 PROS1 gene mutations were detected, and 5 nonsense mutations (c.134_162del/p.Leu45*, c.847G>T/p.Glu283*, c.995_996delAT/p.Tyr332*, c.1359G> A/p.Trp453*, c.1474C>T/p.Gln492*) , 2 frameshift mutations (c.1460delG/p.Gla487Valfs*9 and c.1747_1750delAATC/p.Asn583Wfs*9) and 1 large fragment deletion (exon9 deletion) were reported for the first time. In addition, the PS:C of the deep vein thrombosis during pregnancy case was 55.2 U/dL carrying PROC gene c.565C>T/p.Arg189Trp mutation. Conclusion: The newly discovered gene mutations enriched the PROS1 gene mutation spectrum which associated with inherited PS deficiency.

Whole-exome sequencing in diagnosing 2 cases of Gitelman syndrome / 中南大学学报(医学版)

Two patients with Gitelman syndrome were admitted to the Department of Endocrinology, Third Xiangya Hospital of Central South University. The genomic DNA from the patients' peripheral blood was extracted and the whole-exome sequencing was performed to detect the possible mutations. The function of the mutation sites was analyzed by bioinformatics software. Through whole-exome sequencing and Sanger sequencing, we have found that 2 patients with Gitelman syndrome carried compound heterozygous mutations of SLC12A3 gene, which were c.486_490delTACGGinsA, p.R943W, p.D486N, and p.R928C. Among them, c.486_490delTACGGinsA insertion deletion mutation causes frame shift and protein truncation. The p.R943W, p.D486N, and p.R928C of SLC12A3 gene were predicted to be pathogenic mutations by SIFT, PolyPhen2, and Mutation Taster. These 4 mutations were all reported, but p.R943W was first reported in Chinese population. Gitelman syndrome is rare in clinic and the rate of missed diagnosis is high. Early genetic analysis in patients with Gitelman syndrome is helpful to determine the etiology and guide the treatment.