Resumo Fundamento: As cardiopatias congênitas (CCs) são as anomalias congênitas mais comuns, e têm sido associadas a anormalidades cromossômicas. Atualmente, a cariotipagem e a análise cromossômica por microarray (CMA) são oferecidas rotineiramente aos pacientes, mas a relação genótipo-fenótipo ainda não foi totalmente estabelecida. Objetivo: Determinar o tipo e a frequência das anomalias cromossômicas em fetos com CC e analisar os desfechos da gestação de fetos com anormalidades cardíacas causadas por diferentes fatores genéticos. Métodos: No total, foram admitidos 362 casos de CC entre 2009 e 2016. Ultrassonografia e exames laboratoriais detalhados foram realizados, incluindo cariotipagem e CMA. O resultado foi obtido a partir das folhas de epicrise. Resultados: Dos 362 fetos, 220 apresentaram doença coronariana isolada e 142 apresentaram doença coronariana com anomalia extracardíaca. Entre esses 362 fetos, foram identificados 140 com causa genética, incluindo 111 casos com aneuploidia, 10 casos com anormalidade da estrutura cromossômica por cariotipagem e 19 casos com variações no número de cópias (CNVs) patogênicas ou provavelmente patogênicas por CMA. A taxa de detecção é de aproximadamente 38,7%. Apenas um (identificado como síndrome da trissomia do cromossomo 18) em 140 casos positivos resultou em morte perinatal, com as demais sendo induzidas. Os 222 casos restantes tiveram resultados negativos para ambos os testes genéticos e, destes, 56 resultaram em trabalho de parto induzido e 77 tiveram partos naturais ou cesarianas. O desfecho da gravidez dos 89 casos restantes foi incerto. Conclusões: A cariotipagem e a CMA são técnicas genéticas pré-natais eficazes e precisas para a identificação de anomalias cromossômicas fetais associadas a defeitos cardíacos, e isso pode ajudar os médicos a realizar aconselhamento genético adequado com relação à etiologia e ao desfecho das cardiopatias congênitas.

Abstract Background: Congenital heart defects (CHD), as the most common congenital anomaly, have been reported to be associated with chromosomal abnormalities. Currently, patients with CHD are routinely offered karyotyping and chromosomal microarray (CMA) testing, but the genotype-phenotype relationship has not yet been fully established. Objective: To determine the type and frequency of chromosomal abnormalities in fetuses with CHD and to analyze pregnancy outcomes of fetuses with heart abnormalities caused by different genetic factors. Methods: A total of 362 cases of CHD were enrolled from 2009 to 2016. Detailed ultrasound and laboratory examinations, including karyotyping and CMA, were performed. Outcome was obtained from discharge summaries. Results: Of the 362 fetuses, 220 were found with an isolated CHD, and 142 had CHD with extracardiac anomaly. Among these 362 fetuses, 140 were identified with a genetic cause, including 111 cases with aneuploidy, 10 cases with abnormality of chromosomal structure by karyotyping and 19 cases with pathogenic or likely pathogenic copy-number variations (CNVs) by CMA. The detection rate is close to 38.7%. Only one (identified as trisomy 18 syndrome) in 140 positive cases resulted in perinatal death, with the others being induced. The remaining 222 cases had negative results for both genetic testing and of these cases, 56 resulted in induced labor, and 77 had natural childbirth or caesarean births. The pregnancy outcome of the remaining 89 cases was uncertain. Conclusions: Karyotyping and CMA are effective and accurate prenatal genetic techniques for identifying fetal chromosomal abnormalities associated with cardiac defects, and this can assist clinical doctors to perform appropriate genetic counselling with regard to the etiology and outcome of CHD.

ABSTRACT Objective Pendred syndrome (PS) is an autosomal recessive disorder characterised by sensorineural hearing loss and thyroid dyshormonogenesis. It is caused by biallelic mutations in the SLC26A4 gene encoding for pendrin. Hypothyroidism in PS can be present from birth and therefore diagnosed by neonatal screening. The aim of this study was to examine the SLC26A4 mutation spectrum and prevalence among congenital hypothyroidism (CH) patients in the Guangxi Zhuang Autonomous Region of China and to establish how frequently PS causes hearing impairment in our patients with CH. Subjects and methods Blood samples were collected from 192 CH patients in Guangxi Zhuang Autonomous Region, China, and genomic DNA was extracted from peripheral blood leukocytes. All exons of the SLC26A4 gene together with their exon-intron boundaries were screened by next-generation sequencing. Patients with SLC26A4 mutations underwent a complete audiological evaluation including otoscopic examination, audiometry and morphological evaluation of the inner ear. Results Next generation sequencing analysis of SLC26A4 in 192 CH patients revealed five different heterozygous variations in eight individuals (8/192, 4%). The prevalence of SLC26A4 mutations was 4% among studied Chinese CH. Three of the eight were diagnosed as enlargement of the vestibular aqueduct (EVA), no PS were found in our 192 CH patients. The mutations included one novel missense variant p.P469S, as well as four known missense variants, namely p.V233L, p.M147I, p.V609G and p.D661E. Of the eight patients identified with SLC26A4 variations in our study, seven patients showed normal size/location of thyroid gland, and one patients showed a decreased size one. Conclusions The prevalence of SLC26A4 pathogenic variants was 4% among studied Chinese patients with CH. Our study expanded the SLC26A4 mutation spectrum, provided the best estimation of SLC26A4 mutation rate for Chinese CH patients and indicated the rarity of PS as a cause of CH.

Objetivo O hipotireoidismo congênito disormonogenético (CH) foi relatado como associado a uma mutação no gene simportador sódio/iodeto (NIS). O presente estudo foi feito na região autônoma de Guangxi Zhuang na China para se determinar a natureza e a frequência das mutações no gene NIS entre pacientes com CH causado por disormonogênese. Sujeitos e métodos: Amostras de sangue foram coletadas de 105 pacientes com CH disormonogenéticos e o DNA genômico foi extraído de leucócitos do sangue periférico. Todos os éxons do gene NIS, junto com seus limites éxon-íntron, foram analisados por sequenciamento de nova geração. Resultados Foram encontradas duas variações silenciosas (T221T e T557T) e uma variação missense (M435L), assim como dois polimorfismos (rs200587561 e rs117626343). Conclusões Nossos resultados indicam que a taxa de mutação em NIS é muito baixa na região de Guangxi Zhuang. É necessário estudar mutações de outros genes que tenham efeitos maiores na disormonogênese da tiroide e que ainda não tenham sido estudados nesta população.

Objective Dyshormonogenetic congenital hypothyroidism (CH) was reported to be associated with a mutation in the sodium iodide symporter (NIS) gene. The present study was undertaken in the Guangxi Zhuang Autonomous Region of China, to determine the nature and frequency of NIS gene mutations among patients with CH due to dyshormonogenesis. Subjects and methods: Blood samples were collected from 105 dyshormonogenetic CH patients in Guangxi Zhuang Autonomous Region, China, and genomic DNA was extracted from peripheral blood leukocytes. All exons of the NIS gene together with their exon-intron boundaries were screened by next-generation sequencing. Results Two silent variations (T221T and T557T) and one missense variation (M435L), as well as two polymorphisms (rs200587561 and rs117626343) were found. Conclusions Our results indicate that the NIS mutation rate is very low in the Guangxi Zhuang Autonomous Region, China, and it is necessary to study mutations of other genes that have major effects on thyroid dyshormonogenesis and have not as yet been studied in this population.