Browsing by Author "Correia, Hildeberto"
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- A 1.77 Mb deletion in 3p26.3 encompassing CNTN6 and CNTN4 genes: case reportPublication . Brito, Filomena; Marques, Bárbara; Pedro, Sónia; Serafim, Silvia; Gonçalves, Rui; Freixo, João; Correia, HildebertoChromosome microarray analysis is a powerful diagnostic tool and is being used as a first-line approach to detect chromosome imbalances associated with intellectual disability, dysmorphic features and congenital abnormalities. This test enables the identification of new copy number variants (CNVs) and their association with new microdeletion/microduplication syndromes in patients previously without diagnosis. We report the case of a 7 year-old female with moderate intellectual disability, severe speech delay and auto and hetero aggressivity with a previous 45,XX,der(13;14)mat karyotype performed at a younger age. Affymetrix CytoScan 750K chromosome microarray analysis was performed detecting a 1.77 Mb deletion at 3p26.3, encompassing 2 OMIM genes, CNTN6 and CNTN4. These genes play an important role in the formation, maintenance, and plasticity of functional neuronal networks. Deletions or mutations in CNTN4 gene have been implicated in intellectual disability and learning disabilities. Disruptions or deletions in the CNTN6 gene have been associated with development delay and other neurodevelopmental disorders. The haploinsufficiency of these genes has been suggested to participate to the typical clinical features of 3p deletion syndrome. Nevertheless inheritance from a healthy parent has been reported, suggesting incomplete penetrance and variable phenotype for this CNV. We compare our patient with other similar reported cases, adding additional value to the phenotype-genotype correlation of deletions in this region.
- 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.
- 16p13.11 microduplication: a case reportPublication . Marques, Bárbara; Ferreira, Cristina; Ventura, Catarina; Pedro, Sonia; Antunes, Diana; Nunes, Luis; Correia, HildebertoThe short arm of chromosome 16 is very rich in segmental duplications, predisposing this region of the genome to a number of recurrent rearrangements, namely deletions and duplications. Although it is already known that there is a strong association between 16p13.11 deletion and neuropsychiatric disorders, the clinical significance of its reciprocal duplication is not clearly defined yet. 16p13.11 microduplication that results of non-allelic homologous recombination is a very rare genetic alteration which can be associated with variable clinical features including behavioural abnormalities, developmental delay, congenital heart defects and skeletal anomalies. We report a 7-years-old boy with global developmental delay, speech absence, microcephaly, dysmorphic facial features and inexpressive facies. Microarray analysis revealed a 3.3Mb duplication comprising the 16p13.11- p12.3 region, which was confirmed by fluorescence in situ hybridization with a BAC clone for 16p13.11. Eight annotated genes are present in this region including NDE1, the candidate gene for neurological and behavioural phenotype. Although this microduplication has been found in the normal population, is significantly enriched in patients with autism, schizophrenia and cognitive impairment. Several case reports until now suggest that this genomic abnormality has incomplete penetrance and variable expressivity and can constitute a new syndrome. With this case we intend to contribute to expand the spectrum of clinical findings associated to this genomic abnormality and provide further knowledge of the pathogenic involvement of this duplication.
- A 669Kb deletion in 17q23.2, encompassing TBX2 and TBX4 genes, in a girl with a moderate developmental delay without any other pertinent abnormalityPublication . Ferreira, Cristina; Marques, Bárbara; Pedro, Sónia; Serafim, Silvia; Amorim, Marta; Correia, HildebertoMicrodeletion of the 17q23.1-q23.2 region recently emerged as a syndrome (OMIM#613355) based in a small number of cases with a common phenotype including mild-to-moderate developmental delay, heart defects, microcephaly, postnatal grow retardation, and hand, foot, and limb abnormalities. All patients reported to date present mild to moderate developmental delay, in particular speech delay, and half of them hearing loss. The smallest overlapping region has approximately 2.2 Mb and includes the transcription factors TBX2 and TBX4 genes. These genes have been implicated in a number of developmental pathways, including those of the heart and limbs. The TBX4 gene is also associated with the autosomal dominant small patella syndrome (SPS, OMIM 147891). Here we report a 8 year-old girl with moderate developmental delay including learning disabilities. The test for Fragile X syndrome indicated an allele within the grey area (number of repeats ~50 CGG) inherited from her mother and probably not relevant. Affymetrix Cytoscan HD chromosome microarray analysis was performed and a 669 Kb interstitial deletion was detected at 17q23.2 region, encompassing only five OMIM genes: BCAS3, TBX2, TBX4, NACA2 and BRIP1. To our knowledge this is the smallest deletion described in this region. None of the genes present in the deleted region are known to be associated with developmental problems. We compare our patient with the other similar reported cases, in order to add some increased value to the phenotype-genotype correlation of deletions in this region.
- 6q terminal deletion: a new contribution to genotype-phenotype correlationPublication . Simão, Laurentino; Marques, Bárbara; Sónia, Pedro; Antunes, Diana; Brito, Filomena; Silva, Neuza; Nunes, Luis; Correia, HildebertoDeletion of chromosome 6q is a relatively rare clinical entity associated to a considerable variability of the phenotypic spectrum. Mental retardation, facial dimorphisms, seizures, and brain abnormalities are typical features of this syndrome but until recently genotype-phenotype correlations have been scarce. We report a 15-year-old boy with slight developmental delay, intellectual disability, hypotonia, bilateral eye cataracts, mycrocephaly, agenesis of the corpus callosum, ventriculomegaly, paroxysmal attacks, kyphoscoliosis and trigonocephaly. Cytogenetic analysis revealed a de novo karyotype 46,XY,del(6)(q25.3). Microarrays genomic analysis with Cytoscan 750K allowed the refinement of the breakpoint region to 6q26q27, spanning approximately 7.76 Mb. The variation of the features attributed to 6q deletion syndrome is due primarily to differences in size and location of the segmental aneuploidy. Several studies suggest that deletions of 6q25 region can cause more severe anomalies that those including 6q26-27. Absence of IUGR, ear anomalies, ear loss, cleft palate, cardiac defects and genital hypoplasia in our patient are compatible with studies that generally correlate those features with deletions of 6q25 region. In addition, our patient presents retinal abnormalities, which has been associated to 6q26-q27 deletion. Some new candidate genes, localized at 6qter, have recently been described as being associated with some clinical features; an example is the candidate gene DLL1 and holoprosencephaly. Analysis of the breakpoints in most cases revealed a potential common breakpoint region at 8.0-9.0Mb from the chromosome 6q terminus where a fragile site exists (FRA6E). This suggests the breakage at the FRA6E may be the mechanism behind chromosome 6q subtelomeric deletions in some of the cases.Once the genotype-phenotype correlations have been scarce until now, with this study we aim to contribute to a better knowledge of the genotype-phenotype correlation of 6q terminal deletion and help to identify critical regions for several clinical features and developmental relevant genes.
- 9q21.13q21.31 deletion in a patient with intellectual disability severe speech delay and and dysmorphic features a newly recognized microdeletion syndromePublication . Marques, Barbara; Serafim, Silvia; Pedro, Sonia; Tarelho, Ana Rita; Ferreira, Cristina; Gonçalves, Rui; Correia, HildebertoThe increased use of chromosomal microarray analysis has led to the identification of new microdeletion/microduplication syndromes, enabling better genotype-phenotype correlations. Interstitial deletions involving the long arm of chromosome 9 are rare but recently a microdeletion syndrome at 9q21.13 was suggested, with mental retardation, speech delay, epilepsy, autistic behaviour and moderate facial dysmorphism as the main characteristics. Here we present a male child with intellectual disability, severe speech delay, microcephaly and dysmorphic features carrying an interstitial deletion, detected by the Affymetrix Cytoscan HD microarray, of 6.56 Mb at 9q21.13q21.31 region encompassing 16 OMIM genes (arr[GRCh37] 9q21.13q21.31(76551542_83116342)x1). Among the genes in the deleted region the PRUNE2, PCSK5, RORB and TRPM6 genes are expressed in the nervous system and have been describe as being candidate genes to play a role in mental retardation or neurological disorders. Although the cohort of patients identified with deletions in this region is still small our patient phenotype partially overlaps the others described in the literature. The collection of more cases with deletion of the 9q21.13 region will help establishing a clear classification for this CNV, finding the real weight in the patient’s phenotype, delineating the genetic counseling for their families, and clearly establishing this microdeletion as a syndrome.
- 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
- Análise citogenética num grupo de doentes com Síndrome Mielodisplásico (estudo retrospetivo)Publication . Silva, Maria; Ambrósio, Ana; Silva, Neuza; Ventura, Catarina; Furtado, José; Correia, HildebertoOs Síndromes Mileodisplásicos (SMD) constituem um grupo de patologias clonais heterogéneas, caraterizadas por citopénias; displasia de uma ou mais linhas celulares mieloides e uma hematopoiese ineficaz. A idade média dos pacientes ao diagnóstico é de 70 anos, com uma predominância de ocorrência do sexo masculino e incidência anual de 3-5/100 000 indivíduos. O objetivo deste estudo é realizar uma avaliação retrospetiva dos resultados citogenéticos obtidos em 440 amostras de medula óssea de pacientes com diagnóstico inicial de SMD e tentar obter uma correlação entre os achados citogenéticos e a patologia em estudo. A população estudada por citogenética convencional é constituída por 218 indivíduos do sexo feminino e 222 indivíduos do sexo masculino, com uma idade média de 66 anos. Das 440 amostras analisadas, 104 (23,6% da população total) apresentavam cariotipos anormais. Os cariotipos que apresentavam anomalias foram divididos em: − População A - Cariotipos com uma só anomalia cromossómica (72 amostras) − População B - Cariotipos com duas anomalias cromossómicas (9 amostras) − População C - Cariotipos complexos com três ou mais anomalias cromossómicas (23 amostras) Na população A, a anomalia observada com maior frequência foi a trissomia 8 (25%), seguida da deleção do cromossoma 5 (16,7%), perda do cromossoma Y (15,3%) e deleção do cromossoma 20 (8,3%), estes resultados não se encontram de acordo com os descritos na literatura. Contudo quando se juntam as três populações, verifica-se que a anomalia observada com maior frequência é a deleção do cromossoma 5 (28,8%) o que já se encontra de acordo com o descrito. A perda do cromossoma Y observada nos indivíduos do sexo masculino, não parece estar correlacionada apenas com a idade, mas parece ser um dos fatores que carateriza este grupo de patologias. As anomalias observadas por análise citogenética convencional (uma técnica de baixo custo) permitiram ao clínico uma melhor avaliação de prognóstico e uma decisão terapêutica mais adequada.
- Anemia de Fanconi – Estudo retrospetivo de 34 anosPublication . Ambrósio, Ana Paula; Geraldes, Maria Céu; Correia, HildebertoA Anemia de Fanconi (AF) é uma doença recessiva rara, com uma frequência estimada de 4 a 7 per 1.000.000 de nascimentos. Carateriza-se por malformações congénitas, falência medular e hipersensibilidade a agentes clastogénicos de DNA. Devido à grande complexidade desta patologia a primeira abordagem de diagnóstico, consiste na análise da instabilidade cromossómica, após cultura celular com estimulação com agentes clastogénicos diepoxibutano (DEB) ou mitomicina C (MMC). Realizou-se um estudo retrospetivo de 34 anos (1980-2014) em 243 amostras com suspeita de AF e de 25 amostras de familiares de doentes de AF, num total de 268 amostras. Nas 243 amostras suspeitas de Anemia de Fanconi, foram identificadas 37 com AF. A idade média ao diagnóstico foi de 7 anos, existindo um ligeiro predomínio da incidência no sexo feminino (59%). Uma amostra foi classificada como AF(-/+). Nos familiares de doentes com AF foram identificados 2 casos positivos, o que perfaz 39 amostras de AF positivas. Em quatro das amostras AF negativas, observaram-se cariotipos anormais. Estes resultados não permitem estimar uma frequência de doentes de AF em Portugal, uma vez que não englobam indivíduos de todas as regiões portuguesas, mas permitem uma estimativa da frequência espectável.
- Anemia de Fanconi em Portugal: estudo retrospetivo de 34 anos de investigação no INSA (1980-2014)Publication . Ambrósio, Ana Paula; Silva, Maria do Céu; Furtado, José Manuel; Silva, Neuza; Ventura, Catarina; Viegas, Mónica; Correia, HildebertoA Anemia de Fanconi (AF) é uma doença recessiva rara, com uma frequência estimada de 4 a 7 por 1 000 000 de nascimentos. Caraterizase por malformações congénitas, falência medular e hipersensibilidade a agentes clastogénicos de DNA. Devido à grande complexidade desta patologia a primeira abordagem de diagnóstico, consiste na análise da instabilidade cromossómica, após cultura celular com estimulação com agentes clastogénicos diepoxibutano (DEB) ou mitomicina C (MMC). Realizou- se um estudo retrospetivo de 34 anos (1980-2014) em 243 amostras com suspeita de AF e de 25 amostras de familiares de doentes de AF, num total de 268 amostras. Nas 243 amostras suspeitas de Anemia de Fanconi, foram identificadas 37 com AF. A idade média ao diagnóstico foi de 7 anos, existindo um ligeiro predomínio da incidência no sexo feminino (59%). Uma amostra foi classificada como AF(-/+). Nos familiares de doentes com AF foram identificados 2 casos positivos, o que perfaz 39 amostras de AF positivas. Em quatro das amostras AF negativas, observaram-se cariotipos anormais. Estes resultados não permitem estimar uma frequência de doentes de AF em Portugal, uma vez que não englobam indivíduos de todas as regiões portuguesas, mas permitem uma estimativa da frequência espectável.