Browsing by Author "Tarelho, Ana"
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- 15q11.2q13.1 interstitial gain in a fetus with an increased risk for T21: When classification and clinical outcome are divergentPublication . Serafim, Sílvia; Pedro, Sónia; Marques, Bárbara; Tarelho, Ana; Viegas, Mónica; Simão, Laurentino; Ferreira, Cristina; Carvalho, Inês; Cohen, Álvaro; Correia, HildebertoIntroduction: Copy number variants (CNV) of the 15q11.2q13.1 region are associated to recurrent microdeletion/microduplication syndromes in which the phenotype is dependent on the parental origin of the CNV. We report the case of a fetus from a healthy 39-year-old G6P3A2 woman, with an increased risk for trisomy 21 in the 1st trimester prenatal screening. Chromosomal microarray analysis (CMA) was requested and revealed a pathogenic duplication in which the outcome was dependent of the parental origin of the affected allele. Methods: DNA was extracted from a chorionic villus sample and CMA was performed using Cytoscan™ 750K. Parental follow-up studies to assess the origin of the CNV were performed. Results: The CMA profile revealed a male fetus with a 4,89 Mb interstitial gain in 15q11.2q13.1. CMA of the parents showed that the duplication was paternally inherited. Discussion: The detected CNV is a recurrent known microduplication and according to the American College of Medical Genetics and Genomics guidelines is classified as pathogenic. However the phenotype is dependent on the parental origin of the duplication. When it arises in the maternally allele it has a severe outcome with hypotonia, cognitive deficit, seizures, among others. If the CNV occurs in the paternal allele although some patients might show developmental delays and behavioral disturbances most cases are rarely symptomatic. In this case, CMA of both parents showed that the CNV identified in the fetus was paternally inherited. Although the CMA result did not explained the increased risk for T21 after determining the duplication had been inherited from the father it allowed the prediction of the most likely resulting phenotype for the fetus as a milder or even asymptomatic. Follow-up ultrasounds at gestation age of 17w+6d and echocardiogram at 21w+3d showed no structural abnormalities. The baby was born at 37w+5d with an Apgar index of 10/10/10, with no dysmorphic features or malformations, and a normal physical exam. This case illustrates that although the use of genetic tools using artificial intelligence and following determined guidelines can be helpful for the purpose of consistency and standardization on the classification we always need careful evaluation from a clinical laboratory geneticist on the context of each case. Additionally it also shows how critical parental testing can be, not only to assess recurrence risk but to provide the best possible tool to ascertain the outcoming phenotype and allow the best choices to the couple after genetic counselling.
- Deleção intersticial 7q33q34 em fetos de gravidez gemelar monocoriónica diamnióticaPublication . Simão, Laurentino; Marques, Bárbara; Ferreira, Cristina; Serafim, Sílvia; Alves, Cristina; Silva, Marisa; Viegas, Mónica; Peliano, Ricardo; Brito, Filomena; Bernardeco, Joana; Cruz, Jader; Pedro, Sónia; Martins, Ana; Tarelho, Ana; Carvalho, Inês; Cohen, Álvaro; Correia, HildebertoIntrodução: O acompanhamento de gestações gemelares pode revelar-se desafiante se houver alterações ecográficas e discrepâncias entre os fetos. Deleções intersticiais 7q, abrangendo diferentes regiões e apresentando tamanho variável, são raras, e encontram-se quase exclusivamente descritas em pós-natal. Objectivos: Apresentamos o caso de uma gestante, de 32 anos, com gravidez gemelar monocoriónica e diamniótica de 16 semanas, referenciada por bolsas jugulares bilaterais, crescimento no P10-P20 e discrepância no pico sistólico de velocidade da artéria cerebral média (PSV-ACM). Foi efetuada colheita de liquido amniótico para estudo por microarray cromossómico (CMA). Metodologia: Foi efeituado diagnóstico rápido de aneuploidias (DRA) por QF-PCR (Devyser®), ao que se seguiu CMA com array CytoScan 750K (Thermo Fischer®) e cariótipo. Resultados: O DRA revelou um resultado normal. O CMA permitiu a identificação de uma deleção intersticial com 9,0 Mb em 7q33q34 - arr[GRCh37] 7q33q34(133411316_142427027)x1. A alteração engloba 12 genes mórbidos. O cariotipo confirmou o resultado: 46,XX,del(7)(q32.3q34)dn. Após aconselhamento genético, o casal optou por interrupção da gestação. Conclusões: Deleções intersticiais na região 7q32 a 7q35 apresentam grande variabilidade fenotípica. As características mais comuns são: atraso de desenvolvimento e da linguagem, défice intelectual, dismorfias faciais e atraso de crescimento. Nos raros casos descritos com alterações cromossómicas parcialmente sobreponíveis ao caso em estudo, a CNV tem sido classificada como patogénica. No único caso com referência ao período pré-natal e com alteração quase totalmente sobreponível, descreve-se decréscimo de movimentos fetais, baixo peso à nascença, atraso de desenvolvimento, défice intelectual, dismorfias faciais e infeções múltiplas. A alteração cromossómica encontrada poderá explicar a relativa restrição de crescimento fetal, não tendo as bolsas jugulares, presentes em ambos os fetos e a discrepância PSV-ACM sido até agora descritos. Gestações com alterações ecográficas e CNVs, mas com reduzida bibliografia, são desafiantes na interpretação dos resultados a nível laboratorial e clínico. Só a descrição de mais casos permitirá um ganho de conhecimento em saúde.
- Prenatal diagnosis of Beckwith Wiedemann syndrome: a case reportPublication . Ferreira, Cristina; Tarelho, Ana; Marques, Bárbara; Serafim, Sílvia; Pedro, Sónia; Granja, Carla; Mata, Rodrigo; Martins, Ana Teresa; Carvalho, Inês; Correia, HildebertoBeckwith-Wiedemann syndrome (BWS) is the most common overgrowth disease. Phenotypically and genetically heterogeneous, it is linked with epigenetic/genetic aberrations on 11p15.4p15.5 chromosome region and the majority of cases are diagnosed after birth with prenatal diagnosis being difficult and depending on the identification of specific ultrasound (US) anomalies. Here we present a case of a fetus from a healthy 21-year-old primiparous woman, with a low risk in the first trimester aneuploidy screening and bilaterally increase in renal volume detected in the second trimester US. An amniotic fluid (AF) sample was collected at 24 weeks. Rapid aneuploidy diagnosis by QF-PCR and sequencing of a multigene panel for renal dysplasia were performed with a normal result for common aneuploidies and detection of a variant with uncertain significance, respectively. The pregnant was referred to a differentiated prenatal diagnosis center and a detailed US at 30 weeks and 3 days showed multiple features suggestive of BWS: macroglossia, weight estimation at P100, significantly enlarged kidneys without corticomedullary differentiation, hepatomegaly, prenasal and cervical subcutaneous thickening, and suspected cardiomegaly without structural heart disease. The methylation pattern study of 11p15 region by MS-MLPA revealed hypermethylation of H19/GF2: IG differentially methylated region (DMR), confirming the Beckwith-Wiedemann diagnosis. In contrast to postnatal cases that can be diagnosed by phenotypic scoring, prenatal diagnosis of BWS is relatively challenging because some common features cannot be detected by US and other features appear only after 30 weeks of gestation and may be missed on second-trimester morphological ultrasound. Omphalocele is the most common prenatal phenotypic BWS-associated feature, and is the first and most easily identified in prenatal screening, but there are other features that may suggest BWS such as macroglosia, macrosomia, placental mesenchymal dysplasia, polyhydramnios, and visceromegaly. Routine molecular testing of all fetuses with one or more prenatal BWS-associated features is of utmost importance, as early diagnosis is significantly beneficial for prenatal counselling, perinatal management allowing for better birth planning and postnatal care for neonatal hypoglycemia, respiratory distress, and risk of malignancy.