Browsing by Author "Kay, Teresa"
Now showing 1 - 10 of 10
Results Per Page
Sort Options
- Citogenética de Próxima Geração: Implementação e primeiros resultados em PortugalPublication . David, Dezső; Oliva-Teles, Natália; Freixo, João; Fonseca e Silva, ML; Fortuna, Ana; Tkachenko, Natália; Carvalho, Inês; Marques, Mariana; Cardoso, Manuela; Fino, Joana; Marques, Bárbara; Alves, Ana Cristina; Dória, Sófia; Pinto de Moura, Carla; Marques Carreira, Isabel; Correia, Hildeberto; Gonçalves, Rui Miguel; Lavinha, João; Kay, Teresa; Talkowski, Michael; Morton, CynthiaIntrodução: As alterações cromossómicas estruturais provocam doenças de severidade variável que acarretam sofrimento individual e familiar signifi cativo. Para compreensão da sua etiologia e estabelecimento de um possível prognóstico, uma adequada correlação fenótipo-genótipo é fundamental. O presente estudo faz parte do projeto intitulado àCitogenética de Próxima Geração Irrompe nos Cuidados de Saúde e Contribui para Anotação do Genoma Humanoà, que visa a introdu- ção da sequenciação de próxima geração (NGS) na citogené- tica clínica, tirando partido dessa inovação única na deteção de variantes estruturais, com uma resolução de um nucleótido para a criação de uma citogenética de alto rendimento, catalisadora de notáveis avanços no diagnóstico clínico e resulta da colaboração entre seis Instituições nacionais e a Harvard Medical School. Estima-se que exista um número considerável de indivíduos portadores de diversas patologias, incluindo algumas de início tardio associadas a rearranjos genómicos por identifi car. Assim, é fundamental a identifi cação e a referência destes indivíduos com possíveis rearranjos cromossómicos associados a doenças.
- Congenital adrenal hyperplasia in paediatric age: molecular analysis of the CYP21A2 gene and implications for genetic counsellingPublication . Gomes, Susana; Silva, Júlia; Pereira-Caetano, Iris; Lopes, Lurdes; Limbert, Catarina; Amaral, Daniela; Pina, Rosa; Kay, Teresa; Sampaio, Lurdes; Pereira, Carla; Moldovan, Oana; Berta, Ana; Rebelo, Irene; Gaspar, Isabel; Cidade Rodrigues, José; Lina, Ramos; Ramos, Fabiana; Dinis, Isabel; Cardoso, Rita; Mirante, Alice; Gonçalves, JoãoIntroduction: Congenital adrenal hyperplasia(CAH) is due to 21-hidroxilase deficiency(21-OHD) in about 95% of the cases. 21-OH is encoded by CYP21A2 gene, and most frequent mutations occurring in CYP21A2 are due to gene conversions originated from its pseudogene(CYP21A1P). The clinical severity of CAH is associated with the impairment of 21-OH activity, which is directly related with the molecular defect. CAH is classified as classic salt-wasting(SW) and simple virilising(SV) forms, and nonclassic(NC) form of the disease. SW and SV are usually diagnosed after birth or during the first years of life, respectively, while most cases of NC-CAH are diagnosed during infancy, puberty or until adult age. Here we present the molecular results performed in paediatric patients with CAH.
- Early results of next-gen cytogenetics implementation in PortugalPublication . David, Dezső; Freixo, João; Marques, Bárbara; Carvalho, Inês; Tkachenko, Natália; Oliva-Teles, Natália; Marques, Mariana; Cardoso, Manuela; Fino, Joana; Alves, Cristina; Fortuna, Ana; Sófia, Dória; Pinto de Moura, Carla; Correia, Hildeberto; Marques Carreira, Isabel; Sá, Joaquim; Gonçalves, Rui Miguel; Lavinha, João; Kay, Teresa; Talkowski, Michael; Morton, CynthiaBackground: Most approaches are insensitive to the full mutational spectrum of chromosome rearrangements associated with human developmental abnormalities. Therefore, our aim is to introduce next-generation sequencing (NGS) into clinical cytogenetics, creating a sequence-based NextGen Cytogenetics to catalyze a dramatic advancement in clinical diagnostics. Methods: Twenty families with chromosome rearrangement-associated diseases, including two prenatal (PN) cases, have been enrolled. Fourteen of these were also analyzed by NGS using large-insert paired-end libraries. Results: The majority of these cases were confirmed to be balanced reciprocal rearrangements, whereas 4 were complex chromosomal rearrangements including 1 of chromothripsis. Thus far, over 50 breakpoints were identified disrupting protein coding genes, lncRNAs, or intergenic regions, thus revealing candidate genes or genomic loci. These cases are further assessed for pathogenicity from positional effects on genes located within topological domains (TADs) containing the breakpoints using DECIPHER predictions of haploinsufficiency. In one PN case, the 16q24 breakpoint disrupts ANKRD11, etiologic in the autosomal dominant KBG syndrome (OMIM #148050), predicting an abnormal phenotype. The chromothripsis case, submitted as 46,XY,t(7;14)(q22;q32.1),inv(15)(q21.2q26.1), proved by NGS to carry two further deletions, at 3p12 (5.3 Mb) and 15q14 (488 kb), as well as an insertion of 644.4 kb from 15q14 into 3p14. The inv(15) is in fact a complex rearrangement of 15q with eight breakpoints. Conclusions: We demonstrate that NGS-based chromosomal rearrangement characterization leads to major improvements in identification of chromosomal aberrations and in prediction of clinical outcomes of postnatally and prenatally detected genomic rearrangements, and to contributions to human genome annotation.
- Espectro de alterações moleculares detetadas no gene CYP21A2 associadas a deficiência em 21 hidroxilasePublication . Gomes, Susana; Pereira-Caetano, Iris; Lopes, Maria Lurdes; Limbert, Catarina; Amaral, Daniela; Pina, Rosa; Antunes, Diana; Carvalho, Inês; Kay, Teresa; Sampaio, Lurdes; Pereira, Carla; Moldovan, Oana; Berta, Ana; Rebelo, Irene; Gaspar, Isabel; Cardoso, Helena; Rodrigues, José Cidade; Ramos, Lina; Ramos, Fabiana; Dinis, Isabel; Cardoso, Rita; Mirante, Alice; Gonçalves, JoãoA maioria dos doentes com hiperplasia suprarrenal congénita (HSC) apresenta alterações moleculares no gene CYP21A2, o qual codifica a enzima 21-hidroxilase (21-OH). Os doentes com a forma clássica de deficiência em 21-OH (21-OHD) apresentam a síntese de cortisol diminuída no córtex adrenal e, os casos mais graves, também apresentam deficiência de aldosterona. As mulheres com 21-OHD grave apresentam excesso de andrógenos desde a sua vida fetal conduzindo à virilização dos órgãos genitais externos. Tanto homens como mulheres com 21-OHD completa não sintetizam a aldosterona e, consequentemente, logo após o nascimento, podem desenvolver crises de perda de sal se não forem corretamente diagnosticados e tratados. A 21- OHD não clássica é devida à deficiência parcial em 21-OH, os fenótipos clínicos são menos graves, as mulheres não apresentam virilização dos genitais externos ao nascimento, e geralmente os sinais relativos a excesso de androgénios podem surgir durante a infância ou até mais tarde (durante ou após a puberdade). Neste trabalho descrevem-se as alterações e os genótipos mais frequentes encontrados em doentes portugueses não adultos com 21-OHD. As alterações mais frequentes encontradas na forma clássica da HSC são c.293-13C> G, diferentes deleções/quimeras/conversões génicas do gene CYP21A2 e c.518T> A, enquanto na 21-OHD não-clássica a variante c.844G> T é a mais frequente. Estes resultados contribuem para um diagnóstico correto e uma melhor gestão clínica dos doentes, para o seu aconselhamento genético e para oferecer o diagnóstico pré-natal a casais com risco de ter filhos afetados com a forma clássica de 21-OHD.
- Hiperplasia congénita da supra-renal não clássica (hcsr-nc) por deficiência de 21-hidroxilase: avaliação clínica e aconselhamento genético de duas famílias portuguesasPublication . Matos, Lurdes Godinho; Antunes, Diana; Gomes, Susana; Pereira-Caetano, Iris; Gonçalves, João; Castelo Branco, Sara; Lopes, Lurdes; Kay, TeresaIntrodução: A hiperplasia congénita da supra renal surge por deficiência de 21-hidroxilase em 90-95% dos casos. É uma das doenças hereditárias de transmissão autossómica recessiva mais frequente. A gravidade da doença resulta do grau de deficiência enzimática da 21-hidroxilase, que depende da mutação que ocorre no gene CYP21A2. Pode ter duas apresentações clínicas: a forma clássica (perdedora de sal ou simplesmente virilizante) mais grave e a forma não clássica (ou expressão tardia) com bloqueio enzimático menos grave. Objetivos: Estudo de duas famílias portuguesas com HCSR-NC para melhor avaliação clínica e aconselhamento genético dessas famílias.
- Kallmann Syndrome associated with a large deletion of KAL1 genePublication . Silva, Júlia; Ventura, Célia; Kay, Teresa; Gonçalves, J.Introduction: The Kallmann Syndrome is a clinically and genetically heterogeneous disease, frequently characterized by an association between hypogonadotropic hypogonodism and anosmia or hyposmia. The X-linked form of this syndrome is caused by mutations affecting the KAL1 gene that encodes the extracellular glycoprotein anosmin-1 responsible for the migration of GnRH neurons and olfactory nerves to the hypothalamus. Methods: Molecular diagnosis was performed in a patient with a phenotype of micropenis and strabismus, diagnosed as Kallmann Syndrome. Molecular analysis was performed by PCR and DNA sequencing of the amplified KAL1 exons. Absence of amplification of specific exons was validated by MLPA(Multiplex Ligation-dependent Probe Amplification) in order to confirm a gross gene deletion. Results: The propositus and his mother are carriers of a deletion that comprises exons 4 to 14 detected by PCR and MLPA. Discussion/Conclusion: The patient has a normal male karyotype. Molecular analysis allowed the identification of a large deletion covering exons 4 to 14 of the KAL1 gene. In turn, is mother is heterozygous for this deletion, allowing us to conclude that the patient’s KAL1 gene deletion was inherited, and as expected, is of maternal origin. The patient has a gross deletion of KAL1 that, up to date, is not reported in the scientific literature. Several other KAL1 whole or partial gene deletions have been identified as the cause of this syndrome. In this specific case, the absence of almost the whole KAL1 gene is the molecular basis of the patient phenotype. The identified molecular defect, allowed a better genetic counselling to the nuclear family as well as to other family members.
- Molecular analysis of KAL-1 and GnRHR genes in patients with idiopathic hypogonadotropic hypogonadismPublication . Pereira-Caetano, Iris; Silva, Júlia; Kay, Teresa; Mirante, Alice; Aragüés, José Maria; Mascarenhas, Mário; Gonçalves, JoãoIntroduction: Idiopathic hypogonadotropic hypogonadism (IHH) comprises delayed/absent puberty, infertility and low serum gonadotropins in the context of normal anterior pituitary anatomy and function. Is due to partial/complete absence of gonadotropin-releasing hormone release/action or gonadotropin secretion and its incidence is low (1/10.000-1/86.000) with a nearly 4:1 male-to-female ratio. Approximately two-thirds of individuals with IHH have anosmia or hyposmia (Kallmann syndrome-KS) and one-third have normosmic IHH (nIHH). Mutations in KAL1 gene cause X-linked KS, and in GnRHR gene autosomal recessive IHH (almost 2% of nIHH patients). Material and Methods: 45 patients with IHH (42 males, 3 females), with and without hyposmia/anosmia were studied. Mutation analysis of KAL1 and/or GnRHR was performed by SSCP/DHPLC-PCR or by PCR-direct DNA sequencing. Results: We found two KAL1 mutations: c.769C>T (p.Arg257*) in a 15-years-old anosmic male; and a novel one, an extensive deletion encompassing exons 4 to 14 confirmed by MLPA, in a 3-years-old boy (detected also in his mother) with micropenis and maternal family history of HH. Two nIHH male patients were compound heterozygous for GnRHR: c.[2T>C];[785G>A], p.[(M1T)];[(R262Q)] (39-years-old, prepubertal testicules, gynecomastia, P1-A0 pilosity) and c.[317A>G];[416G>A], p.[(Q106R);(R139H)] (35-years-old with a brother non-tested with similar phenotype). All four mutations are known to be disease-causative. Discussion: We were able to find the genetic defects in 4 patients. The low detection rate of mutations (8.8%) is related with the existence of several genes implicated in the IHH’ pathogenesis. The NGS analysis in patients with IHH may improve the molecular diagnosis as it allows the screening of different genes simultaneously.
- Next-Gen Cytogenetics and the Hidden Complexity of Genomic or Chromosomal RearrangementsPublication . David, Dezső; Freixo, João; Carvalho, Inês; Tkachenko, Natalia; Oliva Teles, Natália; Marques, Bárbara; Alves, Ana Cristina; Fortuna, Ana; Sofia, Dória; Pinto de Moura, Carla; Gaspar, Isabel; Marques Carreira, Isabel; Sá, Joaquim; Gonçalves, Rui; Lavinha, João; Kay, Teresa; Correia, Hildeberto; Talkowski, Michael E.; Morton, Cynthia C.Human developmental abnormalities are devastating conditions that account for almost half of all full-term neonatal deaths in developed countries. For individuals who survive, congenital anomalies often confer lifelong disability and their impact on public health is profound. However, the genetic etiology and genomic architecture contributing to the vast majority of these conditions remain unknown. Separately, and in addition, the genetic etiologies of recurrent infertility remain to be elucidated. The current low resolution diagnostic techniques are insensitive to the full mutational spectrum contributing to human developmental abnormalities and infertility, the poor understanding of the molecular alterations introduced by genomic rearrangements, and the lack of a fully annotated human genome hinders predictive diagnostics. This study results from collaboration between a Portuguese Consortium including clinical geneticists and the Developmental Genome Anatomy Project (DGAP) from Harvard Medical School. First, a group of cases were comparatively analyzed using genomic array and Next-Generation Sequencing (NGS). Subsequently, NGS of whole-genome large-insert libraries was applied for the identification of genomic or chromosomal rearrangements at nucleotide resolution in a series of cases, including two prenatal samples. Presently, this high-throughput technology is the only approach able to identify the full spectrum of structural variants, in a time frame that allows its application even for prenatal samples.The introduction of NGS into clinical cytogenetics surely will create a high-throughput, sequence-based Next-Gen Cytogenetics that will catalyze a dramatic advancement in clinical diagnostics. Therefore the understanding of the molecular pathology of these chromosome rearrangement-associated developmental disorders and infertilities will contribute to an improved prediction of the phenotypic consequences of these rearrangements.
- Nonclassic Congenital Adrenal Hyperplasia (NCCAH) Due to 21-Hydroxylase Deficiency: Clinical Management and Genetic Counseling of Two Portuguese FamiliesPublication . Lurdes de Matos, Maria; Antunes, Diana; Gonçalves, João; Lopes, Lurdes; Kay, TeresaIntroduction: Congenital adrenal hyperplasia (CAH) due to 21-Hydroxylase deficiency occurs in 90-95% of cases, being a common autosomal recessive condition that can present with a wide range of hyperandrogenemic signs in childhood or adulthood. Severity of this disease is correlated with the enzymatic blockade of 21-Hydroxylase which depends of the mutation in gene CYP21A2. Two clinical forms are possible: classic, subdivided in salt-wasting and simple virilizing form (severe) and nonclassic or late onset (less severe). Aims: We studied two portuguese families with NCCAH due to 21-Hidroxilase deficiency in order to improve clinical management and genetic counseling of their members. Methods: Clinical presentation and hormonal assays (including test of tetracosactide) were performed in index cases (IC) . Genomic DNA of each family member was sequenced for the 9 most frequent mutations in CYP21A2. Total deletion of CYP21A , conversion in non functioning CYP21A1P or CYP21A1P_ CYP21A2 quimeras were also analyzed by enzymatic restriction. Results: Family 1- IC: Female, 31 years old with NCCAH diagnosed at age 6 , after investigation of precocious pubarche and with test of tetracosactide positive (17-alpha hydroxyprogesterone levels > 10-15 ng/ml) . Molecular study of CYP21A2 showed a mutation g.1683G> T , homozygous , in CYP21A2 and a non functioning allele of CYP21A2 , heterozygous (non severe 21-Hidroxilase deficiency). Mother was carrying a non functioning allele of CYP21A2 , heterozygous (severe); Father, Brother and Partner were heterozygous for mutation g.1683G> T (non severe). Family 2- IC: Female, 45 years old presenting hirsutism and oligoamenorrhea at age 35 and with test of tetracosactide positive confirming NCCAH Genetic study identified mutation g.1683G> T (less severe) in a copy and g.655A/C>G in another copy (splicing mutation severe). Familial genetic study identified two sisters (age 36 and age 40), asymptomatic but with pathologic genotype confirming NCCAH.
- Prenatal Investigation of a Familial Partial Monosomy 10qPublication . Silva, Marisa; Marques, Bárbara; Brito, Filomena; Ferreira, Cristina; Furtado, José; Ventura, Catarina; Nunes, Luis; Kay, Teresa; Caetano, Paula; Correia, HildebertoObjective: To present the clinical, cytogenetic and molecular findings of a prenatal study of a familial partial monosomy 10q. Distal 10q deletions are rare and the majority are terminal deletions involving bands 10q25 and 10q26. Patients typically present with facial dysmorphism, postnatal growth retardation, developmental and mental retardation, genitourinary anomalies and digital anomalies. Methods: Conventional cytogenetic analysis in metaphases obtained by chorionic villi long term cultures, multiplex ligation dependent probe amplification (MLPA), fluorescent in situ hybridization (FISH), microarray analysis. Results: A 24-year-old gravida was referred for chorionic villus sampling at 12+6 weeks of gestation due to a previous child with facial dysmorphism, bilateral inguinal hernia, short stature and mild to moderate psychomotor delay of whom a microarray analysis was underway. His karyotype was normal but array-CGH analysis disclosed a 10q24.33-q25.1 interstitial deletion. The deletion encompasses 987Kb to 1,14Mb and includes 20 genes, in particular the COL17A gene. Fetal and parental karyotypes were normal. FISH analysis with a BAC clone located within the 10q region deleted in the phenotypically abnormal sibling showed normal results for both the mother and the fetus and a deletion in the apparently normal father. Conclusion: In this case chorionic villi analysis as well as the application of FISH with a specific and targeted BAC clone allowed a shorter turnaround time for the prenatal investigation of the chromosomal abnormality. The authors discuss the challenges of microarray analysis application in the prenatal setting namely in cases like the one presented here where there seems to be phenotypic variability.