Genética Médica
Permanent URI for this community
Browse
Browsing Genética Médica by Title
Now showing 1 - 10 of 21
Results Per Page
Sort Options
- Analysis of human spermatozoa by fluorescence in situ hybridization with preservation of the head morphology is possible by avoiding a decondensation treatmentPublication . Almeida-Santos, T; Dias, C; Brito, R; Henriques, P; Almeida-Santos, APURPOSE: Development of a hybridization technique for spermatozoa allowing the preservation of the head morphology. METHODS: FISH analysis of fixed semen samples from oligoasthenoteratozoospermia (OAT) patients with a normal somatic karyotype attending the Cytogenetics and the IVF Laboratories of a University hospital for semen analysis. In situ hybridization with centromeric probes for chromosomes X, Y, and 18 and locus specific probe for chromosome 21. RESULTS: More than 95% of the sperm heads showed clear hybridization signals and a conserved morphology including the visualization of the tail. Few cells with splitted signals were not considered. CONCLUSIONS: This is the first description of a simple and fast hybridization protocol for spermatozoa without a decondensation step, allowing preservation of the morphology of the sperm head that is particularly useful to correlate abnormal spermatozoa with specific chromosome aneuploidies. With this technique we were able to avoid troubles in interpretation of FISH spots that does not depend on the quality of nuclear decondensation, as it is the case in the previously described methods. Our goal was to demonstrate the efficiency of the method without loosing sperm head morphology. Further studies are needed to correlate the aneuploidy rates for specific chromosomes with sperm morphology.
- Avaliação e Investigação Etiológica do Atraso do Desenvolvimento Psicomotor / Défice IntelectualPublication . Oliveira, R; Rodrigues, F; Venâncio, M; Saraiva, JM; Fernandes, BDevelopmental Delay (DD) and Intellectual Disability (ID), depending on the affected individual being under or above five years-old, result from environmental or genetic causes during the developmental period, that manifest as a subnormal functioning of intellectual abilities. In western countries there is a prevalence of about 3%, with a great impact in the individuals, their families, as well as in the society. Etiologic diagnosis remains unknown in about 65-80% of the cases. It is a clinically heterogeneous condition as it can be sporadic or familiar, encompassing an autosomal dominant, recessive or X-linked transmission. Etiologic investigation emphasizes the importance of the clinical and family history as well as the physical examination, with special care for dysmorphologic evaluation. The authors reviewed DD/ ID focusing not only on clinical diagnosis but mostly on genetic causes and etiologic investigation. The protocol presented is followed by the Medical Genetics Department of Coimbra’s Paediatrics Hospital, in accordance to the international consensus.
- Carcinoma do Endométrio em Mulheres Jovens: caso clínicoPublication . Godinho, I; Sousa, R; Silva, T; Regateiro, FJ; Oliveira, CF; Oliveira, HM
- Copy number variants prioritization after array-CGH analysis - a cohort of 1000 patientsPublication . Carreira, IM; Ferreira, SI; Matoso, E; Pires, LM; Ferrão, J; Jardim, A; Mascarenhas, A; Pinto, M; Lavoura, N; Pais, C; Paiva, P; Simões, L; Caramelo, F; Ramos, L; Venâncio, M; Ramos, F; Beleza, A; Sá, J; Saraiva, J; Barbosa de Melo, JArray-based comparative genomic hybridization has been assumed to be the first genetic test offered to detect genomic imbalances in patients with unexplained intellectual disability with or without dysmorphisms, multiple congenital anomalies, learning difficulties and autism spectrum disorders. Our study contributes to the genotype/phenotype correlation with the delineation of laboratory criteria which help to classify the different copy number variants (CNVs) detected. We clustered our findings into five classes ranging from an imbalance detected in a microdeletion/duplication syndrome region (class I) to imbalances that had previously been reported in normal subjects in the Database of Genomic Variants (DGV) and thus considered common variants (class IV).
- Cytogenetic analysis of spontaneously activated noninseminated oocytes and parthenogenetically activated failed fertilized human oocytes--implications for the use of primate parthenotes for stem cell productionPublication . Almeida-Santos, T; Dias, C; Henriques, P; Brito, R; Barbosa, A; Regateiro, FJ; Almeida-Santos, APURPOSE:Spontaneous parthenogenetically activated noninseminated oocytes and failed fertilized oocytes after ART activated by puromycin were studied to assess cleavage ability and the cytogenetic constitution of the resulting embryos. METHODS: Failed fertilized oocytes were exposed to puromycin, and whenever activation occurred, they were further cultured until arrest of development. FISH was used to assess the ploidy of spontaneous (group A) and induced parthenotes (group B). RESULTS: The mean number of oocytes exposed to puromycin and the percentage and type of activation were identical in IVF and ICSI patients. The more frequent types of activation were one or two pronuclei and one polar body suggesting that retention of the second polar body is a common event after parthenogenetic activation. CONCLUSIONS: Retention of the second polar body and chromosome malsegregation were observed after parthenogenetic activation, either spontaneous or induced by puromycin. This means that using parthenogenetic embryos for stem cell research will require great care and attention.
- Description of an autosomal dominant form of Kabuki syndrome by mutation in MLL2 genePublication . Santos, MI; Beleza-Meireles, A; Loureiro, S; Fonseca, M; Reis, CF; Rodrigues, F; Ramos, F; Ramos, L; Cardoso, E; Saraiva, JMAims: Although there are more than 400 cases of Kabuki syndrome described in the literature, it is believed that this syndrome is under-diagnosed. Most cases occur sporadically, despite cases with autosomal dominant familial transmission being described. Here we describe three cases identified in the same family. Cases description: A family (mother and two children) was diagnosed with Kabuki syndrome. The three patients show the typical characteristics (facial appearance, musculoskeletal abnormalities, cognitive impairment, growth retardation and peculiar dermatoglyphic pattern) associated with other anomalies described in the syndrome (congenital heart disease and increased susceptibility to infections). Genetic studies revealed a nonsense mutation c.14710 C > T (p.Arg4904X) in the MLL2 gene in the three members of the family. Conclusions: With the description of another case of familial Kabuki syndrome, the authors wish to illustrate the autosomal dominant inheritance with variable expressivity, which are present in this situation, and to alert to the need for a rigorous clinical and molecular evaluation of the affected patient’s relatives, allowing appropriate genetic counseling.
- Dilated fetal bowel as indication for prenatal diagnosis of cystic fibrosisPublication . Soares, R; Neto, P; Pereira, N; Cunha, C; Pinto, C; Fonseca, M; Ramos, L; Galhano, EDilated fetal bowel is a sonographic fi nding that is associated to meconium ileus, a feature of cystic fi brosis (CF). Prenatal diagnosis of CF is possible through analysis of the cystic fi brosis transmembrane regulator gene mutations. A male infant is described, who was referred to our Prenatal Diagnosis Center a 17th week of gestation with a dilated bowel loop on a prenatal scan. Amniocentesis was performed at 23rd week gestation and a homozygous F508del mutation was found. He was born at 38 weeks gestation, after an otherwise unremarkable pregnancy, and admitted to Neonatal Intensive Care Unit. He showed progressive abdominal distension without stools and was transferred to another Hospital to surgery. A total occlusion of terminal ileum with meconium and a microcolon were found, and resection of 8 cm of ileum and an ileostomy were performed. The characteristic sonographic fi nding of a dilated bowel is an indication to search for CF mutations.
- Dual use of Diff-Quik-like stains for the simultaneous evaluation of human sperm morphology and chromatin statusPublication . Sousa, AP; Tavares, RS; Velez de la Calle, JF; Figueiredo, H; Almeida, V; Almeida-Santos, T; Ramalho-Santos, JBACKGROUND: Sperm chromatin status and nuclear DNA damage can be detected using well-established assays. However, most techniques are time-consuming and/or involve elaborate protocols and equipment. We have recently developed a simple and fast method to monitor sperm chromatin status in field conditions using the Diff-Quik assay which is employed in fertility clinics to assess sperm morphology with standard bright field microscopy. In the present study, we demonstrate that any Diff-Quik-like stain can easily, reproducibly and routinely monitor human sperm chromatin status as well. METHODS: Different Diff-Quik-like stains were used to assess sperm morphology and the presence of abnormal dark nuclear staining in human sperm from four ART centres. The TUNEL assay was performed in the same samples, and fertility outcomes were assessed. RESULTS: A significant correlation was found between TUNEL-positive sperm and dark sperm nuclei. Moreover, associations were also found between the percentage of dark sperm nuclei and seminal parameters, embryo development rate, embryo quality and clinical pregnancy, as well as with cryptorchidism, and there was a tendency towards an association with age. A value of 32% abnormal staining is suggested as a predictive threshold for embryo development and pregnancy. CONCLUSIONS: Our results show that any Diff-Quik-like stain, already implemented in most laboratories to assess sperm morphology, can be adapted as an indicator for chromatin status in human sperm.
- Gain-of-function mutations in the phosphatidylserine synthase 1 (PTDSS1) gene cause Lenz-Majewski syndromePublication . Sousa, SB; Jenkins, D; Chanudet, E; Tasseva, G; Ishida, M; Anderson, G; Docker, J; Ryten, M; Sá, J; Saraiva, JM; Barnicoat, A; Scott, R; Calder, A; Wattanasirichaigoon, D; Chrzanowska, K; Simandlová, M; Van Maldergem, L; Stanier, P; Beales, PL; Vance, JE; Moore, GELenz-Majewski syndrome (LMS) is a syndrome of intellectual disability and multiple congenital anomalies that features generalized craniotubular hyperostosis. By using whole-exome sequencing and selecting variants consistent with the predicted dominant de novo etiology of LMS, we identified causative heterozygous missense mutations in PTDSS1, which encodes phosphatidylserine synthase 1 (PSS1). PSS1 is one of two enzymes involved in the production of phosphatidylserine. Phosphatidylserine synthesis was increased in intact fibroblasts from affected individuals, and end-product inhibition of PSS1 by phosphatidylserine was markedly reduced. Therefore, these mutations cause a gain-of-function effect associated with regulatory dysfunction of PSS1. We have identified LMS as the first human disease, to our knowledge, caused by disrupted phosphatidylserine metabolism. Our results point to an unexplored link between phosphatidylserine synthesis and bone metabolism.
- Hiperplasia congénita da supra-renal: quando o mesmo genótipo tem diferentes fenótiposPublication . Cordinhã, C; Morais, S; Cardoso, R; Ramos, L; Taborda, A; Mirante, A
- «
- 1 (current)
- 2
- 3
- »