Brazilian Food Reference Guide for Phenylalanine Content: A Study Based on the Perception of PKU Patients and Health Providers

Abstract The mainstay of management of phenylketonuria (PKU) is restriction of dietary phenylalanine (Phe) intake. The present study sought to assess the perception and understanding of health care providers and lay users (patients/family members/caregivers) regarding the national reference database for checking the Phe content of foods, provided by the Brazilian Health Regulatory Agency (Anvisa), whose data are presented in the Table of Phenylalanine Content of Foods (TCFA-Anvisa) and recently in the Phenylalanine Content of Foods Dashboard (PCCFA-Anvisa); and to identify factors which interfere with the usability of these resources. Two online questionnaires, one for providers (n=33) and another for lay users (n=194), were used to collect sociodemographic information, knowledge about dietary management of PKU, sources of information about the Phe content of foods, and perception and understanding of the Anvisa tools. TCFA-Anvisa and PCCFA-Anvisa were not used as main sources of information by either group. Among the participants who had used these tools (15 providers;35 lay users), most considered the PCCFA-Anvisa to be superior or partially superior to the TCFA-Anvisa. The main limitations reported were related to layout and limited variety of foods. We suggest that the limitations identified in this study be considered for future improvement of these resources.

NDUFV1 mutations in complex I deficiency: Case reports and review of symptoms.

Mitochondrial complex I (CI) deficiency is the most common oxidative phosphorylation disorder described. It shows a wide range of phenotypes with poor correlation within genotypes. Herein we expand the clinics and genetics of CI deficiency in the brazilian population by reporting three patients with pathogenic (c.640G>A, c.1268C>T, c.1207dupG) and likely pathogenic (c.766C>T) variants in the NDUFV1 gene. We show the mutation c.766C>T associated with a childhood onset phenotype of hypotonia, muscle weakness, psychomotor regression, lethargy, dysphagia, and strabismus. Additionally, this mutation was found to be associated with headaches and exercise intolerance in adulthood. We also review reported pathogenic variants in NDUFV1 highlighting the wide phenotypic heterogeneity in CI deficiency.

A triple-blinded crossover study to evaluate the short-term safety of sweet manioc starch for the treatment of glycogen storage disease type Ia.

BACKGROUND: Glycogen storage disease type 1a (GSD Ia) is characterized by severe fasting hypoglycemia. The clinical management includes the administration of uncooked cornstarch (UCCS). Although such a diet approach is effective in achieving euglycemia, its impact on the quality of life of patients should be considered. In vitro analyses suggest a longer release of glucose when using sweet manioc starch (SMS). METHODS: We compared the efficacy and safety of the administration of SMS and UCCS during a short-fasting challenge in patients with GSD Ia in a randomized, triple-blind, phase I/II, cross-over study. GSD Ia patients aged ≥ 16 years and treated with UCCS were enrolled. Participants were hospitalized for two consecutive nights, receiving UCCS or SMS in each night. After the administration of the starches, glucose, lactate and insulin levels were measured in 1-h interval throughout the hospitalization period. The procedures were interrupted after 10 h of fasting or in a hypoglycemic episode (< 3.88 mmol/L). RESULTS: Eleven individuals (mean age: 21.6 ± 4.3 years; all presenting body mass index > 25 kg/m2) participated in the study. The average fasting period was 8.2 ± 2.0 h for SMS and 7.7 ± 2.3 h for UCCS (p = 0.04). SMS maintained euglycemia for a greater period over UCCS. Increased lactate concentrations were detected even in absence of hypoglycemia, not being influenced by the different starches investigated (p = 0.17). No significant difference was found in total cholesterol, HDL, triglycerides and uric acid levels in both arms. None of the patients showed severe adverse events. CONCLUSIONS: SMS appears to be non-inferior to UCCS in the maintenance of euglycemia, thus emerging as a promising alternative to the treatment of GSD Ia.

Neurodevelopmental regression, severe generalized dystonia, and metabolic acidosis caused by POLR3A mutations.

OBJECTIVE: To expand the clinical phenotype of POLR3A mutations by assessing the functional consequences of a missense and a splicing acceptor mutation. METHODS: We performed whole-exome sequencing for identification of likely pathogenic mutations in a 9-year-old female patient with severe generalized dystonia, metabolic acidosis, leukocytosis, hypotonia, and dysphagia. Brain MRI showed basal ganglia atrophy and presence of lactate and lipid peaks by [1H]-magnetic resonance spectroscopy. Expression levels of Pol III target genes were measured by quantitative real-time (qRT)-PCR to study the pathogenicity of the biallelic mutations in patient fibroblasts. RESULTS: The patient is a compound heterozygous for a novel missense c.3721G>A (p.Val1241Met) and the splicing region c.1771-6C>G mutation in POLR3A, the gene coding for the catalytic subunit of RNA polymerase III (Pol III). Aberrant splicing was observed for the c.1771-6C>G mutation. Decreased RNA expression levels of Pol III targets (HNRNPH2, ubiquitin B, lactotransferrin, and HSP90AA1) were observed in patient fibroblasts with rescue to normal levels by overexpression of the wild-type protein but not by the p.Val1241Met variant. CONCLUSIONS: Mutations in the POLR3A gene cause POLR3A-related hypomyelinating leukodystrophy with or without oligodontia or hypogonadotropic hypogonadism (HLD7, OMIM: 607694) and neonatal progeroid syndrome (OMIM: 264090), both with high phenotypic variability. We demonstrated the pathogenicity of c.1771-6C>G and c.3721G>A mutations causing an early-onset disorder. The phenotype of our patient expands the clinical presentation of POLR3A-related mutations and suggests a new classification that we propose designating as Neurodevelopmental Disorder with Regression, Abnormal Movements, and Increased Lactate.

Oxidative stress assessment by glutathione peroxidase activity and glutathione levels in response to selenium supplementation in patients with Mucopolysaccharidosis I, II and VI.

We assessed levels of plasma selenium (Se), selenoproteins and their change after Se supplementation in patients with mucopolysaccharidosis (MPS) types I, II and VI. This was done in a retrospective study of the medical records of 30 patients with MPS I (n=13), MPS II (n=9) and MPS VI (n=8) who were being treated with enzyme replacement therapy. As part of routine nutritional monitoring, Se levels were measured, revealing that 28 patients (93.3%) had values below the normal range. Therefore, they received supplementation for 12 months, and Se was measured after 6 and 12 months. Glutathione peroxidase (GPx) activity, total glutathione (GSHt), oxidized glutathione (GSSG) and reduced glutathione (GSH) were measured at baseline and 6 months after Se supplementation. The mean GSHt at baseline was 7.90 ± 2.36 µmol/g Hb, and after Se supplementation it was 5.76 ± 1.13 µmol/g Hb; GSH/GSSG was 2.3 ± 1.16 at baseline and 0.58 ± 0.38 after supplementation. GPx activity was 16.46 ± 3.31 U/g Hb at baseline and 4.53 ± 4.92 U/g Hb after Se supplementation. The difference was shown to be statistically significant by paired t-test. In conclusion, our study demonstrated that oxidative stress parameters were altered by Se supplementation in patients with MPS I, II and VI who were previously deficient in Se.

Evaluation of food intake in patients with mucopolysaccharidosis

Background: Mucopoly saccharidosis (MPS) are inborn errors of metabolism (IEM) recognized by deficient enzymes enrolled in glycosaminoglycans catabolism. The resulting accumulation of glycosaminoglycans leads to clinical progressive and generalized manifestations. Considering the severity of MPS and the relevance of establishing dietetic strategies to these patients, the present study was tailored to evaluate the food intake in patients with MPS types I, II, and VI. Methods: Food intake in patients with MPS I, II, and VI was assessed. A descriptive cross-sectional study was conducted. Energetic demand based on estimated necessity of energy equations and reported food intake was analyzed. Total energetic value and nutrients (vitamins B1, B2, C, calcium, iron, and phosphate) were analyzed inaccordance with the standardized interval for macronutrient distribution and the method of apparent adequacy for nutrient intake. Results: Food intake of 17 patients (6- to 30-year-olds) was considered adequate regarding macronutrients. Children and adolescents failed in presenting this parameter. Macronutrients were satisfactory in both groups. Children and adolescents displayed increased intake of iron and vitamins B1 (p< 0.05), B2, B3, and C (p< 0.077)and probability of adequacy≥50%. Calcium and phosphorus intake was greater in adults. Conclusions: The results obtained demonstrated that patients with MPS have nutrition deficiency in their diet, which may directly or indirectly influence the course of the disease.

Phenylalanine and Tyrosine Metabolism Analysis in Heterozygotes for Phenylketonuria and in Healthy Individuals

Abstract Phenylketonuria (PKU) is an inherited metabolic disorder derived from a deficiency in the enzyme phenylalanine hydroxylase, which converts the amino acid phenylalanine (Phe) into tyrosine (Tyr). Here we aimed to examine the metabolism of Phe and Tyr in heterozygotes for PKU during fasting and after oral overload of Phe (25 mg/kg). Plasma concentration of Phe and Tyr and Phe2-Tyr ratio were determined under fasting condition or 30, 45, 60, and 90 minutes after Phe overload. The sample consisted of 50 participants: 23 heterozygotes for PKU (10 men and 13 women) and a control group of 27 healthy individuals (13 men and 14 women). The dosage of Phe at 45 and 90 minutes and the micromolar fraction of Phe2/Tyr after 90 minutes of overload efficiently differentiated PKU heterozygotes. The discriminant function revealed 86% of accuracy. In fact, 94.4% of heterozygotes for PKU were correctly classified.