Browsing by Author "Correia, Joaquim"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
- 9q34.3 microdeletion by MLPA in a fetus with cardiac defectsPublication . Marques, Bárbara; Ferreira, Cristina; Brito, Filomena; Alves, Cristina; Carvalho, Lucilia; Furtado, José; Ventura, Catarina; Silva, Marisa; Simão, Laurentino; Correia, Joaquim; Correia, Hildeberto
- Gestações gemelares: anomalias cromossómicas em diagnóstico pré-natal (2001-2012)Publication . Brito, Filomena; Simão, Laurentino; Alves, Ana; Silva, Marisa; Furtado, José; Ventura, Catarina; Ambrósio, Paula; Geraldes, Céu; Melo, Antonieta; Correia, Joaquim; Antunes, Diana; Caetano, Paula; Correia, HildebertoIntrodução: As gestações gemelares (GG) têm aumentado significativamente nos últimos anos, sendo este aumento atribuído a um efeito combinado de tratamentos de fertilidade e aumento da idade materna. As grávidas com GG têm um risco acrescido de anomalias cromossómicas fetais, comparativamente às de gestações simples. Objetivo: Avaliação dos resultados obtidos em estudos de Diagnóstico Pré-Natal (DPN) de Anomalias Cromossómicas em gestações gemelares, na Unidade de Citogenética (UCI) do Departamento de Genética Humana do Instituto Nacional de Saúde Dr. Ricardo Jorge, Lisboa, no período de Janeiro de 2001 a Junho de 2012. Material e Métodos: Analisaram-se retrospetivamente casos de GG que efetuaram DPN de anomalias cromossómicas no período considerado. Foram analisados os parâmetros: classificação da gestação, indicação clinica, idade materna, semanas de gestação e resultado do estudo citogenético. Resultados: Num total de 7792 amostras pré-natais analisadas foram consideradas 340, correspondendo a 172 GG. As indicações clínicas mais frequentes foram idade materna (89/172=51.7%) e alterações ecográficas em pelo menos um dos fetos (42/172=24.4%). A idade média das grávidas e do tempo de gestação foi de 34.3 anos e 17.7 semanas respetivamente. Foram detetados 8 cariotipos com alterações cromossómicas, correspondendo a 4.7% das GG. Nas gestações simples a taxa de anomalias cromossómicas observada foi de 5.3% (398/7452). Conclusão: A taxa de anomalias cromossómicas observada nas GG é inferior à observada nas gestações simples no mesmo período de tempo e tipo de amostragem, não correspondendo ao esperado. A taxa de anomalias cromossómicas detetada no total das gestações foi sobreponível aos valores reportados pela DGS.
- Incidental X Linked Findings A female fetus with a gain in the DMD genePublication . Marques, Bárbara; Serafim, Silvia; Pedro, Sónia; Ferreira, Cristina; Simão, Laurentino; Alves, Cristina; Viegas, Mónica; Silva, Marisa; Brito, Filomena; Amorim, Marta; Correia, Joaquim; Correia, HildebertoIn prenatal diagnosis, chromosomal microarray analysis (CMA) has not yet fully replaced conventional cytogenetic but has rapidly become the recommended genetic test in pregnancies with ultrasound abnormalities. This methodology allows the identification of pathogenic small copy number variation (CNVs) in 5-10% of pregnancies with ultrasound abnormalities and a normal karyotype, increasing the diagnostic yield. However, this increased resolution can also result in the detection of incidental findings. Here we report a fetus referred for prenatal diagnosis due to skeletal dysplasia. Affymetrix Cytoscan HD chromosome microarray analysis was performed and a 204 kb gain was detected at Xp21.1 region (chrX: 31993622_32191110 [GRCh37]) in a female fetus, encompassing the intron 44 of the DMD gene, for the largest gene transcript. Nevertheless, if we considered the smaller transcripts it encompasses exon 1. The gain was maternally inherited. The DMD gene is involved on Becker muscular dystrophy, Cardiomyopathy, dilated, 3B and Duchenne muscular dystrophy. Intron 44 is a preferential breakpoint in about 30% of all DMD deletions, being the DMD transcript NM_004006.2 responsible for dystrophin expression in the skeletal muscle.The FGFR3 gene sequencing revealed the presence of the c.1118A >G, p.Y373C mutation associated to Thanatophoric Dysplasia, type 1 (TD1) justifying the ultrasound abnormalities.With this case, we reinforce that the discovery of CNVs in prenatal CMA goes beyond the correlation with the CNV and the ultrasound abnormalities. Incidental findings can also have a larger impact to the family clinical managing, even if not for the ongoing pregnancy for the reproductive future of the couple.
- A retrospective study of Down syndrome in prenatal diagnosis. Did chorionic villus sampling allow a better prevention?Publication . Simão, Laurentino; Silva, Marisa; Brito, Filomena; Alves, Cristina; Marques, Bárbara; Ferreira, Cristina; Ambrósio, Paula; Silva, Maria do Céu; Ventura, Catarina; Duarte, Guida; Caetano, Paula; Correia, Joaquim; Melo, AntonietaIntroduction Down syndrome (DS) is the most common single genetic cause of human moderate mental retardation, with an estimated prevalence of 9.2 cases per 10,000 live births. We aimed at analyzing changes in prenatal diagnosis (PND) over time, namely the referral reasons for chromosome analyses and the introduction of chorionic villus sampling (CVS), and its influence on the results obtained in DS cases. Methods We retrospectively evaluated the PND results from samples analyzed between 1987 and 2011 (25 years) in our cytogenetic laboratory taking into account the referral reasons, type of sample, karyotype and reporting time. Results 263 fetuses with a karyotype compatible with DS were identified in a total of 18,107 karyotypes (1.5%). The highest frequencies of DS were found among cases referred because of ultrasonography findigs (namely increased nuchal translucency) or positive first trimester screening and when one parent carries a chromosomal rearrangement. The frequency of recurrence was found to be 1/72. The increasing use of CVS led to an earlier response in terms of gestational age (mean at diagnosis- 13+4 weeks). In addition, an increased percentage of karyotypes with SD was detected (8.4% of CVS samples). On the other hand, implementation of molecular rapid aneuploidy detection in part of the samples allowed a better report time in DS cases, from 23 days in 1987 to 2 days in 2011. Discussion DS detection remains the most important reason for performing PND. The collecting of CVS has been rising over the last years, which has resulted in an increased number of trisomy 21 cases identified in a lower gestational age, allowing a better karyotype-phenotype correlation in earlier pregnancies. Moreover, the use of complementary molecular techniques for the detection of common aneuploidies reduced the mean reporting time and allowed an earlier decision of the couple concerning the future of gestation.
- Trisomy 15 mosaicism: Challenges in prenatal diagnosisPublication . Silva, Marisa; Alves, Cristina; Pedro, Sónia; Marques, Bárbara; Ferreira, Cristina; Furtado, José; Martins, Ana Teresa; Fernandes, Rosário; Correia, Joaquim; Correia, HildebertoTrisomy 15 mosaicism (mosT15) has been described in fetuses and live-born infants [Christian et al., 1996; Redaelli et al., 2005], with most cases involving confined placental mosaicism (CPM) and meiotic non-disjunction (ND) [EUCROMIC, 1999]. Poor pregnancy outcome prognosis is associated with the presence of aneuploid cells, and there is also a risk of uniparental disomy 15 (UPD15) due to correction of the trisomic state to a disomic constitution. Trisomy or monosomy rescue, gamete complementation and postfertilization error are the main mechanisms leading to UPD and may cause heterodisomy (heteroUPD), isodisomy (isoUPD) or both, depending on the number of meiotic recombinations. The result of maternal (matUPD) and paternal (patUPD) UPD15 is Prader–Willi and Angelman syndrome, respectively, due to imprinting of chromosome region 15q11–15q13. UPD detection can only be achieved using molecular methodologies, such as methylation-specific assays (MSA) [Kotzot, 2008] and, more recently, genome-wide single nucleotide polymorphism (SNP) arrays [Conlin et al., 2010; Schroeder et al., 2013]. MSA allow for methylation pattern analysis of the chromosome regions of interest and SNP-arrays may provide information about copy number as well as UPD, in cases of isoUPD or isodisomy secondary to recombination. HeteroUPD may also be diagnosed by SNParrays if parental and proband DNAs are analyzed in a trio [Conlin et al., 2010; Schroeder et al., 2013]. However, not all molecular methods are equally informative and when a mosaicism is present, especially in a prenatal setting, parent-of-origin analysis as well as karyotype–phenotype correlations become quite challenging. Here we report on a fetus with a CVS diagnosed mosT15 with different degrees of mosaicism found in different tissues and briefly discuss the challenges of prenatal diagnosis of UPD15. (...)