CGMDJM - Artigos publicados em revistas não indexadas na Medline
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- Unraveling the pathogenesis of ARX polyalanine tract variants using a clinical and molecular interfacing approachPublication . Marques, I.; Sá, J.; Soares, G.; Mota, M.; Pinheiro, C.; Aguiar, L.; Amado, M.; Soares, C.; Calado, A.; Dias, P.; Sousa, A.; Fortuna, A.; Santos, R.; Howell, K.; Ryan, M.; Leventer, R.; Sachdev, R.; Catford, R.; Friend, K; Mattiske, T.; Shoubridge, C.; Jorge, P.The Aristaless-related homeobox (ARX) gene is implicated in intellectual disability with the most frequent pathogenic mutations leading to expansions of the first two polyalanine tracts. Here, we describe analysis of the ARX gene outlining the approaches in the Australian and Portuguese setting, using an integrated clinical and molecular strategy. We report variants in the ARX gene detected in 19 patients belonging to 17 families. Seven pathogenic variants, being expansion mutations in both polyalanine tract 1 and tract 2, were identifyed, including a novel mutation in polyalanine tract 1 that expands the first tract to 20 alanines. This precise number of alanines is sufficient to cause pathogenicity when expanded in polyalanine tract 2. Five cases presented a probably non-pathogenic variant, including the novel HGVS: c.441_455del, classified as unlikely disease causing, consistent with reports that suggest that in frame deletions in polyalanine stretches of ARX rarely cause intellectual disability. In addition, we identified five cases with a variant of unclear pathogenic significance. Owing to the inconsistent ARX variants description, publications were reviewed and ARX variant classifications were standardized and detailed unambiguously according to recommendations of the Human Genome Variation Society. In the absence of a pathognomonic clinical feature, we propose that molecular analysis of the ARX gene should be included in routine diagnostic practice in individuals with either nonsyndromic or syndromic intellectual disability. A definitive diagnosis of ARX-related disorders is crucial for an adequate clinical follow-up and accurate genetic counseling of at-risk family members.
- D-bifunctional protein deficiency – a cause of neonatal onset seizures and hypotoniaPublication . Nascimento, J.; Mota, C.; Lacerda, L.; Pacheco, S.; Chorão, R.; Martins, E.; Garrido, C.Background Peroxisomal disorders are classified in two major groups: (1) Peroxisome Biogenesis Disorders and (2) single Peroxisomal Enzyme/Transporter Deficiencies. D-bifunctional protein deficiency (DBP; OMIM #261515) included in this last group of rare diseases leads to an impaired peroxisomal beta-oxidation. D-bifunctional protein deficiencies are classified in four types based on the degree of activity of the 2-enoyl-CoA hydratase and 3-hydroxyacyl-CoA dehydrogenase protein units. Case report/Result The authors present the first portuguese reported type II DBP deficiency patient, whose neonatal clinical picture is indistinguishable from a Zellweger spectrum disease. The clinical features and the neuroimaging findings of polymicrogyria raised suspicion of the diagnosis. After biochemical analysis, DBP deficiency was confirmed with the identification of p.Asn457Tyr (N457Y) mutation, present in homozygosity in HSD17B4 gene. Parents were found to be carriers of the mutated allele, confirming the patient homozygosity status and allowing prenatal diagnosis to future pregnancies. Conclusion D-bifunctional protein deficiency is a rare and severe disease and final diagnosis can only be accomplished after HSD17B4 gene sequencing. Treatment is generally of supportive nature, aimed at improving nutrition and growth, controlling the central nervous system symptoms and limiting the eventual progression of liver disease.
- A 26-Year Experience in Chorionic Villus Sampling Prenatal Genetic DiagnosisPublication . Jorge, P.; Mota-Freitas, M.; Santos, R.; Silva, M.; Soares, G.; Fortuna, A.Abstract: This report describes the trends of chorionic villus sampling (CVS) referred for prenatal genetic diagnosis in the past two and a half decades in a Portuguese Center. Our cohort of 491 CVS was mostly performed by the transcervical method at the 12th gestational week. Data collected within the framework of this study relate to the following: sampling method, referral reason versus abnormality and incidence of procedure-related pregnancy loss, that declined to about 0.5% over the last 15 years. The year 2000 represented a change in referral reasons for chorionic tissue collection, shifting from almost exclusively for cytogenetic testing to an increasing number of molecular tests for monogenic disorders. Herein, success rates as well as cytogenetic and/or molecular DNA results are presented. These latter include not only tests for several monogenic disorders, but also aneuploidy and maternal cell contamination screening. This retrospective analysis reiterates that CVS is a safe and reliable first trimester technique for prenatal diagnosis in high genetic risk pregnancies.