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- Management of Early Treated Adolescents and Young Adults With Phenylketonuria: Development of International Consensus Recommendations Using a Modified Delphi ApproachPublication . Burton, B; Hermida, A; Bélanger-Quintana, A; Bell, H; Bjoraker, K; Christ, S; Grant, M; Harding, C; Huijbregts, S; Longo, N; McNutt, M; Nguyen-Driver, M; Santos Pessoa, A; César Rocha, J; Sacharow, S; Sanchez-Valle, A; Sivri, H; Vockley, J; Walterfang, M; Whittle, S; Muntau, ABackground: Early treated patients with phenylketonuria (PKU) often become lost to follow-up from adolescence onwards due to the historical focus of PKU care on the pediatric population and lack of programs facilitating the transition to adulthood. As a result, evidence on the management of adolescents and young adults with PKU is limited. Methods: Two meetings were held with a multidisciplinary international panel of 25 experts in PKU and comorbidities frequently experienced by patients with PKU. Based on the outcomes of the first meeting, a set of statements were developed. During the second meeting, these statements were voted on for consensus generation (≥70% agreement), using a modified Delphi approach. Results: A total of 37 consensus recommendations were developed across five areas that were deemed important in the management of adolescents and young adults with PKU: (1) general physical health, (2) mental health and neurocognitive functioning, (3) blood Phe target range, (4) PKU-specific challenges, and (5) transition to adult care. The consensus recommendations reflect the personal opinions and experiences from the participating experts supported with evidence when available. Overall, clinicians managing adolescents and young adults with PKU should be aware of the wide variety of PKU-associated comorbidities, initiating screening at an early age. In addition, management of adolescents/young adults should be a joint effort between the patient, clinical center, and parents/caregivers supporting adolescents with gradually gaining independent control of their disease during the transition to adulthood. Conclusions: A multidisciplinary international group of experts used a modified Delphi approach to develop a set of consensus recommendations with the aim of providing guidance and offering tools to clinics to aid with supporting adolescents and young adults with PKU.
- Biochemical and Anthropometric Outcomes in Paediatric Patients with Heterozygous Familial Hypercholesterolemia after COVID-19 Pandemic Lockdowns: An Exploratory AnalysisPublication . Peres, M; Moreira-Rosário, A; Padeira, G; Gaspar Silva, P; Correia, C; Nunes, A; Garcia, E; Faria, A; Teixeira, D; Calhau, C; Pereira-da-Silva, L; Ferreira, AC; César Rocha, JThe COVID-19 pandemic lockdowns affected the lifestyles of children and adolescents, leading to an increase in childhood obesity. Paediatric patients with familial hypercholesterolemia (FH) may be more susceptible to lockdown effects due to their increased cardiovascular risk. However, data are lacking. We investigated the effect of lockdowns on the metabolic profile of paediatric patients with FH. Blood lipids and anthropometry measured in September 2021-April 2022 were retrospectively compared with pre-pandemic values. Thirty participants were included (1-16 years; 57% female). From baseline to post-pandemic, median [P25, P75] blood LDL-C concentration was 125 [112, 150] mg/dL vs. 125 [100, 147] mg/dL (p = 0.894); HDL-C was 58 [52, 65] mg/dL vs. 56 [51, 61] mg/dL (p = 0.107); triglycerides were 64 [44, 86] mg/dL vs. 59 [42, 86] mg/dL (p = 0.178). The BMI z-score did not change significantly (0.19 [-0.58, 0.89] vs. 0.30 [-0.48, 1.10], p = 0.524). The lack of deterioration in metabolic profiles during lockdowns is positive, as some deterioration was expected. We speculate that patients and caregivers were successfully educated about healthy lifestyle and dietary habits. Our results should be interpreted with caution since the study sample was small and heterogeneous. Multicentre research is needed to better understand the impact of lockdowns on this population.
- Suitability and Allocation of Protein-Containing Foods According to Protein Tolerance in PKU: A 2022 UK National ConsensusPublication . Gama, MI; Adam, S; Adams, S; Allen, H; Ashmore, C; Bailey, S; Cochrane, B; Dale, C; Daly, A; De Sousa, G; Donald, S; Dunlop, C; Ellerton, C; Evans, S; Firman, S; Ford, S; Freedman, F; French, M; Gaff, L; Gribben, J; Grimsley, A; Herlihy, I; Hill, M; Khan, F; McStravick, N; Millington, C; Moran, N; Newby, C; Nguyen, P; Purves, J; Pinto, A; César Rocha, J; Skeath, R; Skelton, A; Tapley, S; Woodall, A; Young, C; MacDonald, AIntroduction: There is little practical guidance about suitable food choices for higher natural protein tolerances in patients with phenylketonuria (PKU). This is particularly important to consider with the introduction of adjunct pharmaceutical treatments that may improve protein tolerance. Aim: To develop a set of guidelines for the introduction of higher protein foods into the diets of patients with PKU who tolerate >10 g/day of protein. Methods: In January 2022, a 26-item food group questionnaire, listing a range of foods containing protein from 5 to >20 g/100 g, was sent to all British Inherited Metabolic Disease Group (BIMDG) dietitians (n = 80; 26 Inherited Metabolic Disease [IMD] centres). They were asked to consider within their IMD dietetic team when they would recommend introducing each of the 26 protein-containing food groups into a patient’s diet who tolerated >10 g to 60 g/day of protein. The patient protein tolerance for each food group that received the majority vote from IMD dietetic teams was chosen as its tolerance threshold for introduction. A virtual meeting was held using Delphi methodology in March 2022 to discuss and agree final consensus. Results: Responses were received from dietitians from 22/26 IMD centres (85%) (11 paediatric, 11 adult). For patients tolerating protein ≥15 g/day, the following foods were agreed for inclusion: gluten-free pastas, gluten-free flours, regular bread, cheese spreads, soft cheese, and lentils in brine; for protein tolerance ≥20 g/day: nuts, hard cheeses, regular flours, meat/fish, and plant-based alternative products (containing 5−10 g/100 g protein), regular pasta, seeds, eggs, dried legumes, and yeast extract spreads were added; for protein tolerance ≥30 g/day: meat/fish and plant-based alternative products (containing >10−20 g/100 g protein) were added; and for protein tolerance ≥40 g/day: meat/fish and plant-based alternatives (containing >20 g/100 g protein) were added. Conclusion: This UK consensus by IMD dietitians from 22 UK centres describes for the first time the suitability and allocation of higher protein foods according to individual patient protein tolerance. It provides valuable guidance for health professionals to enable them to standardize practice and give rational advice to patients.
- Body Composition Evaluation and Clinical Markers of Cardiometabolic Risk in Patients with PhenylketonuriaPublication . Luengo-Pérez, LM; Fernández-Bueso, M; Ambrojo, A; Guijarro, M; Ferreira, AC; Pereira-da-Silva, L; Moreira-Rosário, A; Faria, A; Calhau, C; Daly, A; MacDonald, A; Rocha, JCCardiovascular diseases are the main cause of mortality worldwide. Patients with phenylketonuria (PKU) may be at increased cardiovascular risk. This review provides an overview of clinical and metabolic cardiovascular risk factors, explores the connections between body composition (including fat mass and ectopic fat) and cardiovascular risk, and examines various methods for evaluating body composition. It particularly focuses on nutritional ultrasound, given its emerging availability and practical utility in clinical settings. Possible causes of increased cardiometabolic risk in PKU are also explored, including an increased intake of carbohydrates, chronic exposure to amino acids, and characteristics of microbiota. It is important to evaluate cardiovascular risk factors and body composition in patients with PKU. We suggest systematic monitoring of body composition to develop nutritional management and hydration strategies to optimize performance within the limits of nutritional therapy.
- Rare Primary Dyslipidaemias Associated with Low LDL and HDL Cholesterol Values in PortugalPublication . Alves, AC; Miranda, B; Moldovan, O; Espírito Santo, R; Gouveia Silva, R; Soares Cardoso, S; Diogo, L; Seidi, M; Sequeira, S; Bourbon, MBackground: Dyslipidaemia represents a group of disorders of lipid metabolism, characterized by either an increase or decrease in lipid particles, usually associated with triglycerides, LDL cholesterol (LDL-C) and/or HDL cholesterol (HDL-C). Most hyperlipidaemias and HDL deficiencies confer an increased cardiovascular risk, while hypolipidaemia, such as abeta or hypobetalipoproteinemia, may present different manifestations ranging from poor weight progression to neurological manifestations. The aim of this study is to present 7 cases with rare dyslipidaemias associated with low LDL or low HDL cholesterol values, referred to our laboratory for the genetic identification of the cause of the dyslipidaemia. Methods: Lipid profile was determined for each individual in an automated equipment Integra Cobas (Roche). Molecular analysis was performed by NGS with a target panel of 57 genes involved in lipid metabolism (Sure select QXT, Agilent) and samples were run in a NextSEQ Sequencer (Illumina). Only genes associated to rare forms of low HDL-c or LDL-c were analysed for this work, namely: ABCA1, APOA1, LCAT, SCARB1, APOB, PCSK9, MTTP, SAR1B, and ANGPTL3. All rare variants (MAF<5%) found in these genes were confirmed by Sanger sequencing. Results and discussion: This study includes 7 index cases (IC), with the following clinical diagnoses: Fish Eye Disease (1), Hypoalphalipoproteinemia (1) and Abetalipoproteinemia (ABL) / Familial Hypobetalipoproteinemia (FHBL) (5). We have identified one IC with a compound heterozygosity in LCAT causing Fish Eye Disease and one IC with a variant in ABCA1 in homozygosity causing Tangier disease. We found variants causing homozygous FHBL in 2 IC, one of whom has an undescribed pathogenic variant in homozygosity in APOB (c.12087+1G>A) and the other is a possible compound heterozygous for APOB variants c.2604+1G>A and c.4651C>T/p.(Gln1551*). In two patients only a variant in heterozygosity (c.3365delG/p.(Gly1122Vfs*62) and c.11095A>T/p.(Arg3699*)). In the remaining patient, no variants were identified. NGS proved to be a fundamental key for genetic testing of rare lipid disorders, allowing us to find the genetic cause of disease in 6/7 patients with low HDL-c and LDL-c. Patients with these rare conditions should be identified as early as possible in order to minimize or prevent clinical manifestations. The unsolved case is still under investigation.
- Unveiling the Metabolic Effects of GlycomacropeptidePublication . Pena, MJ; Costa, R; Rodrigues, I; Martins, S; Guimarães, JT; Faria, A; Calhau, C; Rocha, JC; Borges, NFor many years, the main nitrogen source for patients with phenylketonuria (PKU) was phenylalanine-free amino acid supplements. Recently, casein glycomacropeptide (GMP) supplements have been prescribed due to its functional and sensorial properties. Nevertheless, many doubts still persist about the metabolic effects of GMP compared to free amino acids (fAA) and intact proteins such as casein (CAS). We endeavour to compare, in rats, the metabolic effects of different nitrogen sources. Twenty-four male Wistar rats were fed equal energy density diets plus CAS (control, n = 8), fAA (n = 8) or GMP (n = 8) for 8 weeks. Food, liquid intake and body weight were measured weekly. Blood biochemical parameters and markers of glycidic metabolism were assessed. Glucagon-like peptide-1 (GLP-1) was analysed by ELISA and immunohistochemistry. Food intake was higher in rats fed CAS compared to fAA or GMP throughout the treatment period. Fluid intake was similar between rats fed fAA and GMP. Body weight was systematically lower in rats fed fAA and GMP compared to those fed CAS, and still, from week 4 onwards, there were differences between fAA and GMP. None of the treatments appeared to induce consistent changes in glycaemia, while insulin levels were significantly higher in GMP. Likewise, the production of GLP-1 was higher in rats fed GMP when compared to fAA. Decreased urea, total protein and triglycerides were seen both in fAA and GMP related to CAS. GMP also reduced albumin and triglycerides in comparison to CAS and fAA, respectively. The chronic consumption of the diets triggers different metabolic responses which may provide clues to further study potential underlying mechanisms.
- Congenital Disorders of Glycosylation in Portugal—Two Decades of ExperiencePublication . Quelhas, D; Martins, E; Azevedo, L; Bandeira, A; Diogo, L; Garcia, P; Sequeira, S; Ferreira, AC; Teles, EL; Rodrigues, E; Fortuna, AM; Mendonça, C; Fernandes, HC; Medeira, A; Gaspar, A; Janeiro, P; Oliveira, A; Laranjeira, F; Ribeiro, I; Souche, E; Race, V; Keldermans, L; Matthijs, G; Jaeken, JObjective: To describe the clinical, biochemical, and genetic features of both new and previously reported patients with congenital disorders of glycosylation (CDGs) diagnosed in Portugal over the last 20 years. Study design: The cohort includes patients with an unexplained multisystem or single organ involvement, with or without psychomotor disability. Serum sialotransferrin isoforms and, whenever necessary, apolipoprotein CIII isoforms and glycan structures were analyzed. Additional studies included measurement of phosphomannomutase (PMM) activity and analysis of lipid-linked oligosaccharides in fibroblasts. Sanger sequencing and massive parallel sequencing were used to identify causal variants or the affected gene, respectively. Results: Sixty-three individuals were diagnosed covering 14 distinct CDGs; 43 patients diagnosed postnatally revealed a type 1, 14 a type 2, and 2 a normal pattern on serum transferrin isoelectrofocusing. The latter patients were identified by whole exome sequencing. Nine of them presented also a hypoglycosylation pattern on apolipoprotein CIII isoelectrofocusing, pointing to an associated O-glycosylation defect. Most of the patients (62%) are PMM2-CDG and the remaining carry pathogenic variants in ALG1, ATP6AP1, ATP6AP2, ATP6V0A2, CCDC115, COG1, COG4, DPAGT1, MAN1B1, SLC35A2, SRD5A3, RFT1, or PGM1. Conclusions: Portuguese patients with CDGs are presented in this report, some of them showing unique clinical phenotypes. Among the 14 genes mutated in Portuguese individuals, 8 are shared with a previously reported Spanish cohort. However, regarding the mutational spectrum of PMM2-CDG, the most frequent CDG, a striking similarity between the 2 populations was found, as only 1 mutated allele found in the Portuguese group has not been reported in Spain.
- Pyruvate Dehydrogenase Complex Deficiency: Updating the Clinical, Metabolic and Mutational Landscapes in a Cohort of Portuguese PatientsPublication . Pavlu-Pereira, H; Silva, MJ; Florindo, C; Sequeira, S; Ferreira, AC; Duarte, S; Rodrigues, AL; Janeiro, P; Oliveira, A; Gomes, D; Bandeira, A; Martins, E; Gomes, R; Soares, S; Tavares de Almeida, I; Vicente, JB; Rivera, IBackground: The pyruvate dehydrogenase complex (PDC) catalyzes the irreversible decarboxylation of pyruvate into acetyl-CoA. PDC deficiency can be caused by alterations in any of the genes encoding its several subunits. The resulting phenotype, though very heterogeneous, mainly affects the central nervous system. The aim of this study is to describe and discuss the clinical, biochemical and genotypic information from thirteen PDC deficient patients, thus seeking to establish possible genotype-phenotype correlations. Results: The mutational spectrum showed that seven patients carry mutations in the PDHA1 gene encoding the E1α subunit, five patients carry mutations in the PDHX gene encoding the E3 binding protein, and the remaining patient carries mutations in the DLD gene encoding the E3 subunit. These data corroborate earlier reports describing PDHA1 mutations as the predominant cause of PDC deficiency but also reveal a notable prevalence of PDHX mutations among Portuguese patients, most of them carrying what seems to be a private mutation (p.R284X). The biochemical analyses revealed high lactate and pyruvate plasma levels whereas the lactate/pyruvate ratio was below 16; enzymatic activities, when compared to control values, indicated to be independent from the genotype and ranged from 8.5% to 30%, the latter being considered a cut-off value for primary PDC deficiency. Concerning the clinical features, all patients displayed psychomotor retardation/developmental delay, the severity of which seems to correlate with the type and localization of the mutation carried by the patient. The therapeutic options essentially include the administration of a ketogenic diet and supplementation with thiamine, although arginine aspartate intake revealed to be beneficial in some patients. Moreover, in silico analysis of the missense mutations present in this PDC deficient population allowed to envisage the molecular mechanism underlying these pathogenic variants. Conclusion: The identification of the disease-causing mutations, together with the functional and structural characterization of the mutant protein variants, allow to obtain an insight on the severity of the clinical phenotype and the selection of the most appropriate therapy.
- Complex Phenotype of Hypercholesterolemia in a Family with Both ABCG8 and APOB MutationsPublication . Ferreira, AC; Alves, AC; Medeiros, AM; Padeira, G; Bourbon, MFamilial hypercholesterolemia is a common genetic hypercholesterolemia caused by mutations in LDLR, APOB and PCSK9 that leads to premature atherosclerosis. Other rare disorders like sitosterolemia can present the same phenotype but have distinct therapeutic interventions. We present a case of severe hypercholesterolemia in a 5-year-old child found to have both familial hypercholesterolemia and sitosterolemia. The proband was diagnosed initially as familial hypercholesterolemia, but the lack of pathogenic variants with Sanger approach questioned this hypothesis. High levels of sitosterol established the diagnosis of sitosterolemia, genetically confirmed by an ABCG8 homozygous variant c.1974C>G/p. (Tyr658*). Next-generation sequencing re sequence for familial hypercholesterolemia genes revealed an APOB heterozygous functional variant (c.11477C>T/p. (Thr3826Met), in a region previously unstudied. The mother presented with the same genotype but a milder phenotype. Control of low-density lipoprotein cholesterol levels was only accomplished with dietary and therapeutic intervention for both sitosterolemia and familial hypercholesterolemia. The correct diagnosis of dyslipidemia is important to establish proper dietary and pharmacological intervention for atherosclerosis prevention.
- Mitochondrial Carbonic Anhydrase VA Deficiency in Neonatal Hyperammonemic Encephalopathy: Case ReportPublication . Sequeira, SHyperammonemia can be a potentially fatal disorder, secondary to several different etiologies, most commonly urea cycle defects and organic acidurias. The deficiency of mitochondrial carbonic anhydrase VA, a recently recognized metabolic disorder, results from abnormalities in the CA5A gene. This gene plays an important role in ureagenesis and gluconeogenesis, resulting in a secondary deficiency of several carboxylases and presenting as neonatal hyperammonemic encephalopathy. We describe the case of an almost 5-year-old child who had neonatal encephalopathy secondary to hyperammonemia wherein carbonic anhydrase VA deficiency was identified in him. His growth and development are normal despite no diet or medication for several years. We report this case as fewer than 20 patients have been described in the literature.
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