Body Composition in Adolescent PKU Patients: Beyond Fat Mass

Current Insights into Nutritional Management of Phenylketonuria: An Update for Children and Adolescents

Considering the fact that even today in the 21st century, diet is the basis of the treatment in phenylketonuria (PKU), this review aims to provide a comprehensive analysis of existing current data from the last 15 years on dietary treatment and its impact on nutritional status and quality of life to identify gaps in knowledge and offer insights into future directions for optimizing nutritional care in PKU. Dietary treatment for PKU has evolved over the years, and in order to optimize and standardize the care, European PKU experts developed guidelines useful for both professionals and patients and their parents. The current literature underscores the essential role of diet in both managing PKU and preventing obesity, but malnutrition in these children is a complex issue that necessitates a multifaceted approach. The literature emphasizes the crucial role of dietary adherence in managing PKU. Advancements in therapy offer the potential to reduce the challenges associated with dietary phenylalanine (Phe) restrictions. Maintaining adequate levels of essential nutrients in children with PKU and monitoring trace element intake and micronutrient levels are vital for preventing deficiencies and ensuring optimal growth and development. Overall, the literature highlights the importance of personalized treatment strategies. Conclusions. Effective management of PKU necessitates strict dietary control and personalized treatment to maintain optimal blood Phe levels. Continuous monito-ring, nutritional education, and adherence to dietary recommendations are critical components in achieving the best patient outcomes. Future studies should also explore innovative therapeutic modalities, including gene therapy and novel dietary strategies that consider the gut-brain axis, to enhance the quality of life and mental health for individuals with PKU.

Novel Insights Into Gyrate Atrophy of the Choroid and Retina (GACR): A Cohort Study

Gyrate atrophy of the choroid and retina (GACR, OMIM #258870) is a rare inherited metabolic disorder characterized by progressive chorioretinal degeneration and hyperornithinemia. Current therapeutic modalities potentially slow disease progression but are not successful in preventing blindness. To allow for trial development, increased knowledge of the clinical phenotype and current therapeutic outcomes is required. In this study, we analyzed 27 patients with GACR. The median age at inclusion was 24 years (range 8-58), with a median age at diagnosis of 14 years (range 0-42). Symptoms began at a mean age of 9 years (range 0-21). Mixed-models analysis showed a significant association between dietary natural protein intake and plasma ornithine levels. Ornithine increased significantly with age, independent of dietary natural protein intake. We found no statistically significant association between ornithine levels and best-corrected visual acuity over time. Patients who started a natural protein-restricted diet below 10 years of age had better VF outcomes compared to patients that started at a later age. MR spectroscopy was used to asses cerebral creatine deficiency, which was present in 15/20 patients, of whom 10 were supplemented with creatine at the time. Finally, using the Michigan Retinal Degeneration Questionnaire, we provided a first insight into the vision-related disability reported by patients with GACR and showed that higher foveal sensitivity was associated with less perceived disability. To conclude, this study provides insights into the phenotype, genotype, biochemistry, and treatment effects of GACR, which can be used for care pathways and clinical trial design.

Intake Modalities of Amino Acid Supplements: A Real-World Data Collection from Phenylketonuria Patients

BACKGROUND

To achieve a normal nutritional status, patients suffering from phenylketonuria (PKU) are typically prescribed amino acid (AA) supplements with low or no phenylalanine (Phe) content. Studies evaluating patient preferences regarding the intake modalities of AA supplements are limited. This study aimed to collect real-world data regarding prescription adherence and intake modalities of AA supplements reported by PKU patients while monitoring metabolic control.

METHODS

This cross-sectional study included 33 PKU patients (16 female and 17 male) with a mean age of 27.2 years. Questionnaires were provided to assess information on AA supplement intake, such as prescription adherence rate, frequency and timing of administration, supplement formulation, and combination with food or drinks. Plasma phenylalanine levels were monitored during the study period.

RESULTS

51.5% (n = 17) of patients reported to lay within an adherence range of 75-100%. The majority of patients consumed AA supplements twice daily, with breakfast (87.9%) and afternoon snacks (51.5%). Powder supplements were most commonly used (72.7%) and often combined with milk and/or fruit juices (45.4%).

CONCLUSIONS

Despite the known concerns related to treatment compliance among PKU adolescents and adults, most of the study participants reported a high level of adherence to AA supplement prescription. The personalized dietary regimens followed by the patients included in the current study represent a treatment approach that might be worth trying in non-compliant patients.

Body Composition Evaluation and Clinical Markers of Cardiometabolic Risk in Patients with Phenylketonuria

Cardiovascular 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.