Este website utiliza cookies que facilitam a navegação, o registo e a recolha de dados estatísticos.
A informação armazenada nos cookies é utilizada exclusivamente pelo nosso websiteAo navegar com os cookies ativos consente a sua utiliza

Saber mais Aceitar Cookies


Bone health and micronutrients status evaluation in phenylalanine dietary restricted patients

Investigador: Sandra Mexia
Instituição: Metabolic Unit, Reference Center for Metabolic Diseases, CHULN-HSM, Lisbon, Portugal


Phenylketonuria (PKU) dietary management involving protein restriction remains an effective treatment of the disease preventing neurocognitive compromise. The goal is to limit the accumulation of toxic amounts of phenylalanine (Phe), an essential amino acid. A combination of natural protein and Phe-free, tyrosine rich formulas are needed to provide adequate amounts of tyrosine for growth and neurotransmitter synthesis, with just enough Phe for anabolism. Although, long term protein restricted diets can lead to suboptimal bonne health outcomes, potentially leading to growth failure and fractures.
Authors intend to perform a retrospective study to evaluate the bonne health of PKU patients followed at Lisbon Reference Center for Inborn Errors of Metabolism, CHULN, concerning bonne mineralization and fracture risk.
The clinical charts of all PKU patients summitted to dual energy X-ray absorptiometry (DEXA) evaluation will be reviewed regarding:
1. Mineral bonne density by DEXA, according to patient´s age and gender;
2. Demographic data regarding gender, age, puberty status, dietary compliance, type, duration and frequency of exercise and fracture occurrence;
3. Energy, protein (natural and synthetic), calcium, phosphorus, magnesium and vitamin D daily intake in the patient´s diet and pharmacological supplementation, previous to DEXA evaluation;
4. Plasma biochemical evaluation of calcium, phosphorus, magnesium, alkaline phosphatase, vitamin D, parathyroid hormone (PTH), median Phe levels and urinary calcium excretion, previous to DEXA evaluation;
5. Anthropometric data (weight, height and body mass index), according to World Health Organization (WHO) percentiles and z-scores to gender and age, at the time of DEXA evaluation;
6. Calcium content of amino acid mixtures, glycomacropeptide (GMP) intake and Kuvan supplementation will also be addressed.

There is no animal testing.

Saiba mais



Does phenylalanine restricted diet impacts microbiota in patients with phenylketonuria?

Investigador: Catarina Isabel dos Santos Rodrigues.
Instituição: Nutrition and Metabolism, NOVA Medical School | Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal. CINTESIS - Center for Health Technology and Services Research, Porto, Portugal.

ABSTRACT: Phenylketonuria (PKU) is a rare autosomal recessive inborn error of phenylalanine (Phe) metabolism due to a deficiency of the hepatic-based enzyme phenylalanine hydroxylase. Dietary treatment is the cornerstone of therapy and its goal is to prevent excessive Phe accumulation in the blood.

The gut microbiota plays a major role in the maintenance of the host health, including intestinal health and function. It is influenced by several factors, including dietary pattern, antibiotic exposure, mode of delivery of a neonate, among others. However, dietary pattern is one of the most important, as it strongly influences the composition of gut microbiota. This may be particularly relevant in PKU patients, since their special Phe- restricted diet begins in the neonatal period and is maintained throughout life, possibly modifying gut microbiota composition and affecting gut homeostasis.

This study aims to i) characterize the gut microbiota of adult PKU patients; ii) compare gut microbiota of adult PKU patients with healthy adult population; and iii) understand the role of the Phe-restricted diet as a potential inducer of gut dysbiosis.

This will be an observational, cross-sectional study. A total of 24 participants will be recruited from the National Reference Centre in Hereditary Metabolic Disorders, Centro Hospitalar de Lisboa Norte. Anthropometric data of the population will be collected, and body composition will be assessed by bioimpedance, after overnight fasting. Faecal samples will be collected, as well as food records from the three days prior to faecal sample collection. Data from medical records will also be collected, including prescribed protein substitutes, natural and total daily protein intakes, median blood Phe concentrations in the previous year preceding the study, and clinical relevant data.

Saiba mais



Melhoramento das novas tabelas de composição do teor e dos aminoácidos a utilizar como ferramenta para o tratamento das doenças hereditárias do metabolismo proteico

Investigador:  Carla Vasconcelos
Instituição:  Unidade de Nutrição e Dietética do Centro Hospitalar São João. Centro de Referência de Doenças Metabólicas do Centro Hospitalar Universitário São João

As Doenças Hereditárias do Metabolismo (DHM) são patogênicas raras de natureza genética em que uma metabolização pode ser destruída. A proteína é uma proteína enzimática, que é uma variável via metabólica, tendo uma acumulação de compostos (muitas vezes tóxicos) e uma produção diminuída ou um produto biológico importante (Scriver et al., 2001). A deficiência enzimática é devida a uma mutação numérica de vários genes codificantes para o passo metabólico em causa. Como aminoácidos e ácidos orgânicos, tais como aminoácidos e sob o ponto de vista fisiológico são incluídos no grupo de intoxicação por doenças, ou seja, doenças que causam sintomas de intoxicação aguda e progressiva, por acumulação de metabolismo tóxico ao aumento do bloqueio enzimático.
Saiba mais



The effect of the nitrogen source on metabolism in Phenylketonuria

Investigador: Maria João Pena, PhD Student, FMUPorto  
Instituição: Faculdade de Medicina da Universidade do Porto, Porto

Since Phenylketonuria’s (PKU) treatment introduction in 1950’s by Dr. Horst Bickel, many advances were made. In fact, one of the major contributions to PKU was the implementation of a phenylalanine (Phe)-restricted diet, remaining the cornerstone of treatment. The Phe-restricted diet consists of natural protein supplemented with protein substitutes (PS). Phe-free amino acid mixtures (AAM) are still the most common PS used to treat patients with PKU, despite the recent emergence of glycomacropeptide-based PS (GMP). GMP is an intact protein derived from cheese making process. There may be metabolic discrepancies between AAM and GMP, particularly at gycidic metabolism level. Several mechanisms can explain these differences, such as, the incretins release and the gut microbiota. Nevertheless, the scientific evidence is still scarce. This project comprises animal and clinical studies.
The main objective of the present research is to understand the effect of different nitrogen sources used for the treatment of PKU on metabolism.

Saiba mais




Challenges in long-term management of MSUD: a prospective study by assessment of clinical, Biochamical and Anthropometric Parameters

Investigador: Sandra Mexia
Instituição: Centro Hospitalar de Lisboa Norte, Hospital de Santa Maria

Maple syrup utine disease (MSUD - OMIM # 24860) is a rare unherited sidorder of branched-chain amino acids (BCAAs) - leucine (Leu), isoleucine (lLe) and valine (Val), displaying an autosomal recessive pattern of inheritance, and caused by deficiency of branched-chain aketo acid dehydrogenase, the enzymatic complex responsible for the breaking down of byproducts of the BCAAs transmination reactioin, the corresponding branched-chain a-keto-acids (BCKA).
The disruption of this metabolic pathway results in the accumulation of BCAAs and BCKA in cells and fluis of the body, which present neurotoxic, especially Leu and the corresponding a-keto-acid, the a-keto-isocaproic acid (KIC). To avoid life-threatening complications, treatment must promptly be strated. MSUD's treatment, primarily nutritional, is based on manipulation of a restricted natural protein diet with reduced BCAAs content and supplementation eith synthetic formulas for the supplying of essential amino acids and micronutrients, pivotal for ensuring normal grosth and psychomotor development of effected children.

Saiba mais


Estado de micronutrientes e ingestão de misturas de aminoácidos isentas de fenilalanina, em doentes fenilcetonúricos 

Investigador: Paula Cristina Ramos
Instituição: Centro de Genética Médica, Centro Hospitalar do Porto, Porto

Consulte Grelha de Avaliação



Elaboração de tabelas com composição quantitativa de aminoácidos e teor proteico de um conjunto de produtos hortícolas e leguminosas de origem nacional a partir da realização de perfil de aminoácidos desses alimentos 

Investigador: Carla Vasconcelos
Instituição: Unidade de Doenças Metabólicas do Centro Hospitalar São João, Porto

Uma das importantes fontes proteicas dos planos alimentares dos doentes com Doenças Hereditárias do Metabolismo Proteico são os produtos hortícolas e as leguminosas. Este estudo procura atualizar os dados referentes às alterações no mercado alimentar português e, simultaneamente, sistematizar essa informação em bases de dados ou tabelas de composição, possibilitando aos doentes uma melhor escolha, em prol da sua saúde.

Saiba mais



Efeito da mistura de aminoácidos livre de fenilalanina em parâmetros metabólicos 

Investigador: Maria João Pena
Instituição: FMUP – Porto

Neste estudo procura-se estabelecer relação entre a dieta particular utilizada nos doentes com PKU e alguns parâmetros metabólicos, ainda não estudados nesta patologia. Em particular, pretende-se determinar se a mistura de aminoácidos livre de fenilalanina é responsável pela diminuicão dos níveis plasmaticos de glicose em ratos.

Saiba mais



Faculdade de Farmácia da U.L.
Av. Prof. Gama Pinto
1649-003 Lisboa

Contacto: Fernanda Asper
Telefone.: +351 217 946 400
Fax: +351 217 946 491


Subscreva a newsletter da SPDM - Sociedade Portuguesa de Doenças Metabólicas