Adriana Pané

Background: Phenylketonuria (PKU) is a rare metabolic disorder caused by a deficiency in the enzyme phenylalanine hydroxylase, leading to the accumulation of phenylalanine (Phe). Raised Phe levels can result in neurocognitive deficits, intellectual disabilities, and behavioral or psychiatric disorders. Aim of review: To conduct a systematic review of human studies on metabolites identified through metabolomics in individuals with PKU, compared to healthy controls, and to provide insights into their biological significance. Key scientific concepts of review: A total of 26 human studies analyzing metabolites in urine and blood met the inclusion criteria. In total, 544 metabolites that differed between patients with PKU and healthy controls were identified through different metabolomic techniques (LC-MS, GC-MS, NMR). Differences were primarily observed in blood samples, which accounted for 95% of the total metabolites, with only 5% detected in urine samples, reflecting the limited use of this body fluid in only five studies. We found 60% of blood metabolites upregulated in patients with PKU, including Phe, Phe-related metabolites, lipids, and other amino acids, while tryptophan and kynurenine, among others, were downregulated (40%). Additionally, 35 metabolites (6% of the total) exhibited inconsistent directions of change (both up- and downregulated), including amino acids, carnitine derivatives, and lipids. These findings may be attributed to clinical factors (dietary adherence, supplementation, and treatment) and methodological differences in blood-derived matrices. Consequently, the high heterogeneity across studies, biological matrices and analytical platforms represents limitations for establishing a unique metabolomic signature. Overall, these results emphasize the metabolic complexity of PKU and highlight the potential of metabolomics to advance disease monitoring and management.

Background/Objectives: Inborn errors of metabolism (IEM) are chronic, life-threatening genetic disorders with a significant cumulative prevalence worldwide. Advances in early diagnosis and treatment have significantly increased life expectancy, underscoring the need for specialised adult care units and the establishment of structured transition programmes from paediatric to adult services. We hereby present a functional transition model for IEM patients and share our implementation experience. Methods: Initiated in 2012, the partnership between the paediatric Hospital Sant Joan de Déu (HSJD) and the adult-care centre at Hospital Clinic of Barcelona (HCB) culminated in 2019 with the transference of the first IEM patients under the structured A10! Programme. This model is structured around the transition units of paediatric and adult centres to guarantee communication and functional management. Regular monthly meetings at each centre and joint quarterly sessions allowed for protocol harmonisation and personalised care planning. Coordinated engagement of the multidisciplinary health care teams with patients and families smoothed the transfer process. Results: Between 2019 and 2024, 94 IEM patients were successfully transferred. Diagnoses included intermediary metabolism defects (71.23%), lipid metabolism and transport disorders (4.25%), heterocyclic compound metabolism (2.12%), complex molecules and organelle dysfunction (6.37%), cofactor and mineral metabolism (2.12%), signalling defects (5.31%), and unclassified cases (8.51% of rare disorders, maybe non-IEM). Transition formats included 21 in-person joint visits in HSJD, 37 remote transitions during the COVID-19 pandemic, and 36 streamlined transfers via standardised protocols. Sessions, trainings, and meetings allowed the exchange of patients’ needs and protocols. Conclusions: The successful transference of IEM patients requires structured programmes with interdisciplinary paediatric and adult teams, joining efforts with the patient, families, and caregivers. Communication between paediatric and adult transition units is essential to promote continuity of care and patient empowerment. While constantly updated, this model has proven effective, gaining positive evaluations from healthcare professionals and patients alike, representing a scalable framework for lifelong management of IEM in adult care settings.

Phenylketonuria (PKU) is a rare inherited metabolic disorder caused by phenylalanine hydroxylase deficiency, leading to phenylalanine (Phe) accumulation and neurological dysfunction if untreated. While metabolomics holds promise for biomarker discovery in PKU, few studies have examined urinary metabolites using untargeted approaches. This study applied untargeted metabolomics using HPLC-QTOF-MS to analyze urine from 36 adult patients with PKU and 34 healthy controls. Biomarker Analysis was performed with MetaboAnalyst 6.0. A total of 73 significant metabolites (FDR < 0.05; VIP > 1) were identified, with 29 upregulated and 44 downregulated in PKU. A 23% of these metabolites were related to Phe metabolism, while 77% were associated with alterations across more than 10 metabolic pathways, including leucine and tryptophan metabolism, acylcarnitines, vitamins, and diet- or microbiota-derived compounds, among others. Specifically, upregulated metabolites with an AUC > 0.9 included several Phe-derived compounds, the nucleoside 8-hydroxy-7-methylguanine, and indole compounds (1H-indole-3-carboxaldehyde). Conversely, downregulated metabolites with an AUC > 0.9 included N-acetyl(iso)leucine and a heptenoylcarnitine isomer. The Random Forest-based model demonstrated enhanced predictive performance when integrating 10 metabolites, supporting their potential utility as biomarkers for PKU. These findings improve the biological understanding of metabolic disturbances beyond Phe, and may support the development of new therapeutic and dietary strategies.

Background: Altered white matter (WM) is consistently reported in patients with phenylketonuria (PKU). However, the knowledge about WM microstructural integrity in early-treated adults with classical PKU and its relationship with cognition and metabolic parameters is inconclusive. This study aims to explore the cerebral WM microstructural alterations in adult patients with early-treated classical PKU and their association with blood phenylalanine (Phe) levels and neuropsychological performance using whole-brain diffusion tensor imaging (DTI). Methods: Twenty-nine patients with early-treated classical PKU (mean age = 30.86, SD = 7.74) and 31 healthy controls (mean age = 32.45, SD = 9.40) underwent neuropsychological assessment and MRI. Phe dry blood spot (DBS-Phe) samples, along with venous Phe levels, were collected from the PKU sample to calculate the index of dietary control (IDC). Tract-based spatial statistics (TBSS) of the mean diffusivity (MD), and fractional anisotropy (FA), were carried out with FSL v6.0.4 to assess between-group differences and to explore associations with both cognitive and clinical data. Results: Patients exhibited a widespread white matter tract involvement, with lower MD and higher FA values compared to controls. The most affected tracts were the inferior longitudinal fasciculus and inferior fronto-occipital fasciculus for MD, and the anterior corona radiata, uncinate fasciculus and forceps minor for FA. MD negatively correlated with IDC and venous Phe levels, whereas FA negatively correlated with full-scale intelligence quotient (FSIQ) (p-value ≤0.05 FWE-corrected). Conclusions: Microstructural WM alterations were present in adults with early-treated classical PKU, and these abnormalities were related to global intelligence and metabolic control markers. Although our results suggest the importance of proper disease management, further studies are needed to determine its long-term relevance.

A 90-year-old male was admitted to the hospital due to recurrent symptomatic hypoglycemia. After ruling out the most common outpatient causes of hypoglycemia, endogenous hyperinsulinism was confirmed. An abdominal computed tomography (CT) scan revealed a 15 mm solid nodular lesion in the pancreatic tail. The (68)Ga-DOTA-TOC PET-CT findings led to the diagnosis of insulinoma. A multidisciplinary committee considered the patient unfit for surgery. The treatment was started with a low dose of diazoxide; however, side effects appeared as the dose was gradually increased. Consequently, a dietary approach was prioritized, incorporating modified cornstarch (Glycosade®) in fractionated doses administered under the guidance of continuous glucose monitoring. This strategy allowed for a reduction in the diazoxide dosage and effectively prevented further hypoglycemic episodes without additional side effects. Since the initial medical treatment was successful, the patient and his family preferred to avoid other possible minimally invasive treatments unless pharmacological and dietary approaches failed.

Background: Continued dietary treatment since early diagnosis through newborn screening programs usually prevents brain-related complications in phenylketonuria (PKU). However, subtle neurocognitive and brain alterations may be observed in some adult patients despite early treatment. Nevertheless, neuropsychological and neuroimaging studies in the field remain scarce.Objectives: This work aimed to determine possible neuropsychological and structural brain alterations in treated adult patients with PKU.Methods: Thirty-five patients with PKU and 22 healthy controls (HC) underwent neuropsychological assessment and T1-weighted magnetic resonance imaging on a 3 T scanner.FreeSurfer(v.7.1) was used to obtain volumetric measures and SPSS (v27.0.1.0) was used to analyze sociodemographic, neuropsychological, volumetric, and clinical data (p < 0.05).Results: Adult patients with PKU showed significantly lower performance than HC in Full Scale IQ (t = 2.67;p = .010) from the WAIS-IV. The PKU group also showed significantly lower volumes than HC in the pallidum (U = 224.000;p = .008), hippocampus (U = 243.000;p = .020), amygdala (U = 200.000;p = .002), and brainstem (t = 3.17;p = .006) as well as in total cerebral white matter volume (U = 175.000;p = .001). Blood phenylalanine (Phe) levels in PKU patients were negatively correlated with the pallidum (r = -0.417;p = .013) and brainstem (r = -0.455,p = .006) volumes.Conclusions: Adult patients with early-treated PKU showed significantly lower global intelligence than HC. Moreover, these patients showed reduced global white matter volume as well as reductions in the volume of several subcortical grey matter structures, which might be related to the existence of underlying neurodevelopmental alterations. Higher blood Phe levels were also negatively correlated with pallidum and brainstem, suggesting a higher vulnerability of these structures to Phe toxicity.

The use of gut-hormone receptors agonists as new therapeutic options for obesity and some of its related comorbidities, such as type 2 diabetes, has resulted in an unprecedented efficacy in the medical management of people living with obesity (PLWO). Appraisal of the safety of these drugs is of utmost importance considering the large number of PLWO, and the potentially long exposure to these pharmacotherapies. In this narrative review we summarize the evidence on the safety of liraglutide, semaglutide, and tirzepatide as derived from randomized clinical trials conducted in adults living with obesity. Additionally, the safety of these drugs is put into perspective with that of other drugs currently approved for the treatment of PLWO. Overall, the available data support a favorable efficacy versus safety balance for gut-hormone hormone receptor analogues in the treatment of these subjects. Nonetheless, it should be acknowledged that in the context of a chronic disease that has reached epidemic proportions, data from randomized clinical trials aimed primarily at proving the efficacy of these drugs may have been insufficient to unveil all the safety issues. Thus, continuous surveillance on the adverse effects of liraglutide, semaglutide, and tirzepatide is required as we use these drugs in a broader population than that represented in currently available clinical trials.

Phenylketonuria (PKU) is the most frequent of the congenital errors of amino acid (AA) metabolism worldwide. It leads to the accumulation of the essential AA phenylalanine (Phe) and it is associated with severe neurological defects. The early diagnosis and treatment of this rare disease, achieved through newborn screening and low-Phe diet, has profoundly changed its clinical spectrum, resulting in normal cognitive development. We face the first generation of PKU patients perinatally diagnosed and treated who have reached adulthood, whose special needs must be addressed, including feeding through enteral nutrition (EN). However, recommendations regarding EN in PKU constitute a gap in the literature. Although protein substitutes for patients with PKU are offered in multiple forms (Phe-free L-amino acid or casein glycomacropeptide supplements), none of these commercial formulas ensures the whole provision of daily total energy and protein requirements, including a safe amount of Phe. Consequently, the combination of different products becomes necessary when artificial nutrition via tube feeding is required. Importantly, the composition of these specific formulas may result in physicochemical interactions when they are mixed with standard EN products, leading to enteral feeding tubes clogging, and also gastrointestinal concerns due to hyperosmolality. Herein, we present the first reported case of EN use in an adult patient with PKU, where the separate administration of protein substitutes and the other EN products avoided physicochemical interactions.

Lysinuric protein intolerance (LPI) is a rare inborn error of metabolism (IEM), classified as an inherited aminoaciduria, caused by mutations in the SLC7A7 gene, leading to a defective cationic amino acid transport. The metabolic adaptations to the demands of pregnancy and delivery cause significant physiological stress, so those patients affected by IEM are at greater risk of decompensation. A 28-year-old woman with LPI had experienced 3 early miscarriages. While pregnancy was finally achieved, diverse nutritional and medical challenges emerged (food aversion, intrauterine growth restriction, bleeding risk, and preeclampsia suspicion), which put both the mother and the fetus at risk. Moreover, the patient requested a natural childbirth (epidural-free, delayed cord clamping). Although the existence of multiple safety concerns rejected this approach at first, the application of novel strategies made a successful delivery possible. This case reinforces that the woman’s wish for a non-medicated, low-intervention natural birth should not be automatically discouraged because of an underlying complex metabolic condition. Achieving a successful pregnancy is conceivable thanks to the cooperation of interdisciplinary teams, but it is still important to consider the risks beforehand in order to be prepared for possible additional complications.