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- Lipid Antigen Presentation by CD1b and CD1d in Lysosomal Storage Disease PatientsPublication . Pereira, C.; Pérez-Cabezas, B.; Ribeiro, H.; Maia, M.; Cardoso, M.; Dias, A.; Azevedo, O.; Ferreira, M.; Garcia, P.; Rodrigues, E.; Castro-Chaves, P.; Martins, Esmeralda; Aguiar, P.; Pineda, M.; Amraoui, Y.; Fecarotta, S.; Leão-Teles, E.; Deng, S.; Savage, P.; Macedo, M.The lysosome has a key role in the presentation of lipid antigens by CD1 molecules. While defects in lipid antigen presentation and in invariant Natural Killer T (iNKT) cell response were detected in several mouse models of lysosomal storage diseases (LSD), the impact of lysosomal engorgement in human lipid antigen presentation is poorly characterized. Here, we analyzed the capacity of monocyte-derived dendritic cells (Mo-DCs) from Fabry, Gaucher, Niemann Pick type C and Mucopolysaccharidosis type VI disease patients to present exogenous antigens to lipid-specific T cells. The CD1b- and CD1d-restricted presentation of lipid antigens by Mo-DCs revealed an ability of LSD patients to induce CD1-restricted T cell responses within the control range. Similarly, freshly isolated monocytes from Fabry and Gaucher disease patients had a normal ability to present α-Galactosylceramide (α-GalCer) antigen by CD1d. Gaucher disease patients' monocytes had an increased capacity to present α-Gal-(1-2)-αGalCer, an antigen that needs internalization and processing to become antigenic. In summary, our results show that Fabry, Gaucher, Niemann Pick type C, and Mucopolysaccharidosis type VI disease patients do not present a decreased capacity to present CD1d-restricted lipid antigens. These observations are in contrast to what was observed in mouse models of LSD. The percentage of total iNKT cells in the peripheral blood of these patients is also similar to control individuals. In addition, we show that the presentation of exogenous lipids that directly bind CD1b, the human CD1 isoform with an intracellular trafficking to the lysosome, is normal in these patients.
- Congenital disorders of glycosylationPublication . Mendes, Ana Raquel; Quelhas, D; Correia, Joana; Paiva Coelho, Margarida; Bandeira, Anabela; Martins, EsmeraldaCongenital disorders of glycosylation are a highly variable, rapidly expanding family of genetic diseases that result from defects in the synthesis of glycans. The vast majority of these monogenic diseases are inherited in an autosomal recessive way, but some types follow an autosomal dominant or X-linked inheritance. The present work aimed to review the state of the art of congenital disorders of glycosylation, including available therapeutic options, and present a simplified diagnostic approach to this group of diseases. Congenital disorders of glycosylation can be classified into four categories: N-linked glycosylation defects, O-linked glycosylation defects, combined glycosylation defects, and glycosphingolipid and glycosylphosphatidylinositol anchor synthesis defects. The phenotype may range from mild to severe, depending on disease severity. Clinical features include dysmorphic features, neurologic, dermatologic, cardiac, endocrine, immunologic, hematologic, gastrointestinal and liver involvement, and skeletal muscle abnormalities. As there is no universal or pathognomonic sign or symptom and no sensitive diagnostic test, it is of foremost importance to keep a high index of suspicion of these diseases. When a congenital disorder of glycosylation is suspected, the first step in screening is to perform serum transferrin isoelectric focusing. Molecular genetic testing is the most specific diagnostic test. Treatment is usually symptomatic, with specific treatment only available for some of these disorders. Since congenital defects of glycosylation may affect any organ at any age and have variable clinical presentation, they should be considered in the differential diagnosis of any patient with multiorgan involvement.
- TYROSINEMIA TYPE III: A CASE REPORT OF SIBLINGS AND LITERATURE REVIEWPublication . Barroso, Fábio; Correia, Joana; Bandeira, Anabela; Carmona, Carla; Vilarinho, Laura; MF, Almeida; Rocha, Júlio César; Martins, EsmeraldaObjective: Tyrosinemia type III (HT III) is the rarest form of tyrosinemia, and the full clinical spectrum of this disorder is still unknown. The neurological involvement varies, including intellectual impairment and attention deficit disorder with hyperactivity (ADHD). We report the case of two siblings diagnosed with HT III at different ages. Case description: The index case was diagnosed by newborn screening for endocrine and metabolic disorders, starting a low-protein diet immediately, with a consistent decrease in tyrosine levels. By the age of three, the child displayed a hyperactive behavior, starting treatment for ADHD two years later. At seven years of age, he shows a slight improvement in terms of behavior and attention span and has a cognitive performance slightly lower than his peers, despite maintaining acceptable tyrosine levels. His sister, who had a history of ADHD since age five, was diagnosed with HT III after family screening at the age of eight. Despite initiating a dietetic treatment, her behavior did not improve, and she has a mild intellectual impairment. Comments: This is the first case report describing siblings with HT III who underwent nutritional treatment with a low-protein diet in different phases of life, with a better neurological and behavioral evaluation in the patient who started treatment earlier.
- Fatty Liver Caused by Glycogen Storage Disease Type IX: A Small Series of Cases in ChildrenPublication . Leuzinger Dias, C.; Maio, I.; Brandão, J.; Tomás, E.; Martins, Esmeralda; Santos Silva, E.Background: The prevalence of non-alcoholic fatty liver disease (NAFLD) affecting children and adolescents has increased dramatically in recent years. This increase is most probably related to the obesity pandemic and the high consumption of fructose. However, hepatic steatosis has some rare causes (e.g., some metabolic diseases) of which clinicians should be aware, particularly (but not only) when patients are non-obese or non-overweight. Differential diagnosis is notably important when pathologies have a specific treatment, such as for glycogenosis type IX (GSD-IX). Aims: To contribute to the knowledge on the differential diagnosis of NAFLD in paediatric age and to the clinical, biochemical, molecular, and histological characterisations of GSD-IX, a rare metabolic disorder. Methods: We performed a retrospective study of a small series of cases (n = 3) of GSD-IX diagnosed in the past 6 years, who were currently being followed up in the Units of Gastroenterology or Metabolic Diseases of the Paediatric Division of our hospital and whose clinical presentation was NAFLD in paediatric age. Results: Three male patients were diagnosed with NAFLD before 2 years of age, 2 with confirmed diagnosis before the age of 3 years (alanine aminotransferase [ALT], liver ultrasound, and molecular analysis) and 1 whose diagnosis was confirmed at 11 years (ALT, liver ultrasound, liver histology, and molecular analysis). None of the patients were obese or overweight, and the daily fructose consumption was unknown. The outcome was favourable in all 3 patients, with follow-up periods ranging from 2 to 6 years. Conclusion: The decision on how far the search for secondary causes of NAFLD should go can be difficult, and GSD-IX must be on the list of possible causes.
- Leigh Syndrome Spectrum: A Portuguese Population Cohort in an Evolutionary Genetic EraPublication . Baldo, Manuela Schubert; Nogueira, Célia; Pereira, Cristina; Janeiro, Patrícia; Ferreira, Sara; Lourenço, Charles M.; Bandeira, Anabela; Martins, Esmeralda; Magalhães, Marina; Rodrigues, Esmeralda; Santos, Helena; Ferreira, Ana Cristina; Vilarinho, LauraMitochondrial diseases are the most common inherited inborn error of metabolism resulting in deficient ATP generation, due to failure in homeostasis and proper bioenergetics. The most frequent mitochondrial disease manifestation in children is Leigh syndrome (LS), encompassing clinical, neuroradiological, biochemical, and molecular features. It typically affects infants but occurs anytime in life. Considering recent updates, LS clinical presentation has been stretched, and is now named LS spectrum (LSS), including classical LS and Leigh-like presentations. Apart from clinical diagnosis challenges, the molecular characterization also progressed from Sanger techniques to NGS (next-generation sequencing), encompassing analysis of nuclear (nDNA) and mitochondrial DNA (mtDNA). This upgrade resumed steps and favored diagnosis. Hereby, our paper presents molecular and clinical data on a Portuguese cohort of 40 positive cases of LSS. A total of 28 patients presented mutation in mtDNA and 12 in nDNA, with novel mutations identified in a heterogeneous group of genes. The present results contribute to the better knowledge of the molecular basis of LS and expand the clinical spectrum associated with this syndrome.
- Continuous use of glycomacropeptide in the nutritional management of patients with phenylketonuria: a clinical perspectivePublication . Pena, Maria João; Pinto, Alex; de Almeida, Manuela Ferreira; de Sousa Barbosa, Catarina; Ramos, Paula Cristina; Rocha, Sara; Guimas, Arlindo; Ribeiro, Rosa; Martins, Esmeralda; Bandeira, Anabela; Dias, Cláudia Camila; MacDonald, Anita; Borges, Nuno; Rocha, Júlio CésarBackground: In phenylketonuria (PKU), modified casein glycomacropeptide supplements (CGMP-AA) are used as an alternative to the traditional phenylalanine (Phe)-free L-amino acid supplements (L-AA). However, studies focusing on the long-term nutritional status of CGMP-AA are lacking. This retrospective study evaluated the long-term impact of CGMP-AA over a mean of 29 months in 11 patients with a mean age at CGMP-AA onset of 28 years (range 15-43) [8 females; 2 hyperphenylalaninaemia (HPA), 3 mild PKU, 3 classical PKU and 3 late-diagnosed]. Outcome measures included metabolic control, anthropometry, body composition and biochemical parameters. Results: CGMP-AA, providing 66% of protein equivalent intake from protein substitute, was associated with no significant change in blood Phe with CGMP-AA compared with baseline (562 ± 289 µmol/L vs 628 ± 317 µmol/L; p = 0.065). In contrast, blood tyrosine significantly increased on CGMP-AA (52.0 ± 19.2 μmol/L vs 61.4 ± 23.8 μmol/L; p = 0.027). Conclusions: Biochemical nutritional markers remained unchanged which is an encouraging finding in adults with PKU, many of whom are unable to maintain full adherence with nutritionally fortified protein substitutes. Longitudinal, prospective studies with larger sample sizes are necessary to fully understand the metabolic impact of using CGMP-AA in PKU.
- SLC35A2-CDG: Novel variant and reviewPublication . Quelhas, D; Correia, Joana; Jaeken, Jaak; Azevedo, Luísa; Lopes-Marques, Mónica; Bandeira, Anabela; Keldermans, Liesbeth; Matthijs, Gert; Sturiale, Luisa; Martins, EsmeraldaSLC35A2 encodes the X-linked transporter that carries uridine diphosphate (UDP)-galactose from the cytosol to the lumen of the Golgi apparatus and the endoplasmic reticulum. Pathogenic variants have been associated to a congenital disorder of glycosylation (CDG) with epileptic encephalopathy as a predominant feature. Among the sixty five patients described so far, a strong gender bias is observed as only seven patients are males. This work is a review and reports a SLC35A2-CDG in a male without epilepsy and with growth deficiency associated with decreased serum IGF1, minor neurological involvement, minor facial dysmorphism, and camptodactyly of fingers and toes. Sequence analysis revealed a hemizygosity for a novel de novo variant: c.233A > G (p.Lys78Arg) in SLC35A2. Further analysis of SLC35A2 sequence by comparing both orthologous and paralogous positions, revealed that not only the variant found in this study, but also most of the reported mutated positions are conserved in SLC35A2 orthologous, and many even in the paralogous SLC35A1 and SLC35A3. This is strong evidence that replacements at these positions will have a critical pathological effect and may also explain the gender bias observed among SLC35A2-CDG patients.
- Utility of Gene Panels for the Diagnosis of Inborn Errors of Metabolism in a Metabolic Reference CenterPublication . Barbosa-Gouveia, Sofia; Vázquez-Mosquera, María E.; González-Vioque, Emiliano; Álvarez, José V.; Chans, Roi; Laranjeira, Francisco; Martins, Esmeralda; Ferreira, Ana Cristina; Avila-Alvarez, Alejandro; Couce, María L.Next-generation sequencing (NGS) technologies have been proposed as a first-line test for the diagnosis of inborn errors of metabolism (IEM), a group of genetically heterogeneous disorders with overlapping or nonspecific phenotypes. Over a 3-year period, we prospectively analyzed 311 pediatric patients with a suspected IEM using four targeted gene panels. The rate of positive diagnosis was 61.86% for intermediary metabolism defects, 32.84% for complex molecular defects, 19% for hypoglycemic/hyperglycemic events, and 17% for mitochondrial diseases, and a conclusive molecular diagnosis was established in 2-4 weeks. Forty-one patients for whom negative results were obtained with the mitochondrial diseases panel underwent subsequent analyses using the NeuroSeq panel, which groups all genes from the individual panels together with genes associated with neurological disorders (1870 genes in total). This achieved a diagnostic rate of 32%. We next evaluated the utility of a tool, Phenomizer, for differential diagnosis, and established a correlation between phenotype and molecular findings in 39.3% of patients. Finally, we evaluated the mutational architecture of the genes analyzed by determining z-scores, loss-of-function observed/expected upper bound fraction (LOEUF), and haploinsufficiency (HI) scores. In summary, targeted gene panels for specific groups of IEMs enabled rapid and effective diagnosis, which is critical for the therapeutic management of IEM patients.
- Neonatal Cholestasis Over Time: Changes in Epidemiology and Outcome in a Cohort of 154 Patients from a Portuguese Tertiary CenterPublication . Santos Silva, Ermelinda; Almeida, Alexandra; Frutuoso, Simão; Martins, Esmeralda; Valente, Maria João; Santos-Silva, Alice; Lopes, Ana IsabelIntroduction: In the last two decades there have been advances in the diagnosis and management of neonatal cholestasis, which may have changed its epidemiology, diagnostic accuracy, outcomes, and survival. Our goal was to characterize these changes over time in our setting. Methods: Retrospective cohort study in a tertiary center, enrolling patients born between January 1985 and October 2019. The cohort was divided into two periods, before (A; n = 67) and after (B; n = 87) the year 2000; and in two groups, according to patient's outcome (favorable, unfavorable). Overall survival and survival with and without orthotopic liver transplant (OLT) were evaluated in the two periods (A and B) and in different subgroups of underlying entities. Results: We found that the age of cholestasis recognition decreased significantly from period A to period B [median 43 days and 22 days, respectively, (p < 0.001)]; the changes in epidemiology were relevant, with a significant decrease in alpha-1-antitrypsin deficiency (p < 0.001) and an increase in transient cholestasis (p = 0.004). A next-generation sequencing (NGS) panel available since mid-2017 was applied to 13 patients with contributory results in 7, but, so far, only in 2 patients led to conclusive diagnosis of underlying entities. The number of cases of idiopathic cholestasis did not vary significantly. Over time there was no significant change in the outcome (p = 0.116). Overall survival and survival without OLT had no significant improvement during the period of observation (in periods A and B, 86 vs. 88%, and 85 vs. 87%, respectively). However, in period B, with OLT we achieved the goal of 100% of survival rate. Conclusions: Our data suggest that transient cholestasis became a very important subset of neonatal cholestasis, requiring specific guidance. The NGS panels can provide important inputs on disease diagnosis but, if applied without strict criteria and expertise, they can open a Pandora's box due to misinterpretation. Despite all the advances in accurate diagnosis and timely management-including early recognition of cholestasis-the improvement in patient outcomes and survival were still not significant.
- Assessing Lysosomal Disorders in the NGS Era: Identification of Novel Rare VariantsPublication . Encarnação, Marisa; Coutinho, Maria Francisca; Silva, Lisbeth; Ribeiro, Diogo; Ouesleti, Souad; Campos, Teresa; Santos, Helena; Martins, Esmeralda; Cardoso, Maria Teresa; Vilarinho, Laura; Alves, SandraLysosomal storage diseases (LSDs) are a heterogeneous group of genetic disorders with variable degrees of severity and a broad phenotypic spectrum, which may overlap with a number of other conditions. While individually rare, as a group LSDs affect a significant number of patients, placing an important burden on affected individuals and their families but also on national health care systems worldwide. Here, we present our results on the use of an in-house customized next-generation sequencing (NGS) panel of genes related to lysosome function as a first-line molecular test for the diagnosis of LSDs. Ultimately, our goal is to provide a fast and effective tool to screen for virtually all LSDs in a single run, thus contributing to decrease the diagnostic odyssey, accelerating the time to diagnosis. Our study enrolled a group of 23 patients with variable degrees of clinical and/or biochemical suspicion of LSD. Briefly, NGS analysis data workflow, followed by segregation analysis allowed the characterization of approximately 41% of the analyzed patients and the identification of 10 different pathogenic variants, underlying nine LSDs. Importantly, four of those variants were novel, and, when applicable, their effect over protein structure was evaluated through in silico analysis. One of the novel pathogenic variants was identified in the GM2A gene, which is associated with an ultra-rare (or misdiagnosed) LSD, the AB variant of GM2 Gangliosidosis. Overall, this case series highlights not only the major advantages of NGS-based diagnostic approaches but also, to some extent, its limitations ultimately promoting a reflection on the role of targeted panels as a primary tool for the prompt characterization of LSD patients.