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- Desenvolvimento neurocognitivo em 99 adolescentes e adultos com fenilcetonúria: ganhos em saúde resultantes de uma abordagem multidisciplinarPublication . Carmona, C.M.; Almeida, M.F.; Rocha, J.C.; Soares, G.; Fortuna, A.
- 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.
- Diagnóstico e benefícios para a comunidade na doença genética: contributo da citogenéticaPublication . Oliva-Teles, N.; Freitas, M.; Lopes, E.; Aguiar, J.; Marques, B.; Fortuna, A.; Silva, M.
- Arx-related disorders: several distinct phenotypes, one mutated genePublication . Sá, M.J.; Soares, G.; Silva, J.; Fortuna, A.; Santos, R.; Marques, I.; Jorge, P.
- Infantile Refsum Disease: Influence of Dietary Treatment on Plasma Phytanic Acid LevelsPublication . Sá, M.; Rocha, J.; Almeida, M.; Carmona, C.; Martins, E.; Miranda, V.; Coutinho, M.; Ferreira, R.; Pacheco, S.; Laranjeira, F.; Ribeiro, I.; Fortuna, A.; Lacerda, L.Infantile Refsum disease (IRD) is one of the less severe of Zellweger spectrum disorders (ZSDs), a group of peroxisomal biogenesis disorders resulting from a generalized peroxisomal function impairment. Increased plasma levels of very long chain fatty acids (VLCFA) and phytanic acid are biomarkers used in IRD diagnosis. Furthermore, an increased plasma level of phytanic acid is known to be associated with neurologic damage. Treatment of IRD is symptomatic and multidisciplinary.The authors report a 3-year-old child, born from consanguineous parents, who presented with developmental delay, retinitis pigmentosa, sensorineural deafness and craniofacial dysmorphisms. While the relative level of plasma C26:0 was slightly increased, other VLCFA were normal. Thus, a detailed characterization of the phenotype was essential to point to a ZSD. Repeatedly increased levels of plasma VLCFA, along with phytanic acid and pristanic acid, deficient dihydroxyacetone phosphate acyltransferase activity in fibroblasts and identification of the homozygous pathogenic mutation c.2528G>A (p.Gly843Asp) in the PEX1 gene, confirmed this diagnosis. Nutritional advice and follow-up was proposed aiming phytanic acid dietary intake reduction. During dietary treatment, plasma levels of phytanic acid decreased to normal, and the patient's development evaluation showed slow progressive acquisition of new competences.This case report highlights the relevance of considering a ZSD in any child with developmental delay who manifests hearing and visual impairment and of performing a systematic biochemical investigation, when plasma VLCFA are mildly increased. During dietary intervention, a biochemical improvement was observed, and the long-term clinical effect of this approach needs to be evaluated.