Background: One of the main objectives of Phenylketonuria (PKU) management is represented by optimising the growth trend under restricted protein diet regimen. The data on long-term growth in PKU children are limited and mostly based on earlier studies. Methods: The data for this twelve-year longitudinal study were collected from 34 PKU children and 37 healthy peers, whose auxological parameters were taken at 7 time-points over the follow-up. The weight-for-length ratio (WLR) z-score and body mass index (BMI) z-score were considered according to age. Prevalence of overweight/obesity was evaluated at last assessment. Results: The median BMI z-score of PKU children was normal and not statistically different from that of controls on all the seven time-point assessments. Their distributions tended to be wider than those of peers, with the upper limit exceeding the normal range since 12 months old, with a peak specifically at 3 years of age. In controls, there was a tendency to approach the BMI z-score values of overweight in later childhood. The prevalence of overweight was comparable (29% vs. 25%, p: 0.78) between the two groups at last assessment, and obese subjects (3/37) were only detected in the control group. Conclusions: In this study, we report data from a long-term follow-up on growth, highlighting that the median BMI z-score of PKU children was normal and not statistically different from that of controls. Also, the prevalence of obesity at 12 years of age was overlapping. However, the high prevalence of overweight children in the general population may explain the lack of difference and does not reassure about patients’ nutritional risk.

Introduction: Protein substitutes (PSs) free of phenylalanine (Phe) represent the primary source of proteins and micronutrients in dietary management of classical Phenylketonuria (PKU). Over the last few years, the composition of PSs has undergone rapid and significant improvements, including the development of slow-release amino acid technologies, the introduction of glycomacropeptide-based products, as well as enhancements in taste and the variety of available formulations. However, their micronutrient content has received limited attention. This work aims to analyse the micronutrient composition of all PS formulations available in Italy for paediatric PKU patients and compare their micronutrient contribution to the recommended dietary allowance (RDA) and assess variability among products and age groups. Materials and Methods: The content of 28 micronutrients was analysed in 63 PSs, grouped according to the age ranges defined by the RDA guidelines: 0–6 months, 6–12 months, 1–3 years, 3–8 years, 8–14 years. The micronutrient content was standardised for 10 g of protein equivalent (PE). Results: Compared to the RDA, many micronutrients were found to be over-supplemented across all age groups, particularly in the 0–6 month group, where peak levels were observed for vitamin K, chromium, and manganese. The 1–3 age group showed the lowest levels of supplementation, with most micronutrients falling within the sub-supplementation range. The variability in supplementation among PSs was broad and showed the highest values in the latter age ranges, reaching maximum levels for biotin and copper. Among different ages, the variability was higher in the first two age ranges, particularly for vitamin A. Choline is not supplemented in many PSs across different age ranges. Conclusions: Many micronutrients supplemented in the PSs exceed the RDA for all age groups, with high variability among different PSs and age groups. When prescribing a PS, the daily amount of synthetic proteins of the diet should be considered in order to evaluate the real daily intake of micronutrients in a PKU diet.

Background/Objectives: Skeletal impairment has been reported as a common finding in Hyperphenylalaninemia (HPA)/Phenylketonuria (PKU) patients regardless of age and method of diagnosis, both in children and adults. Quantitative Ultrasound (QUS) is a radiation-free and low-cost method for assessing bone quality, used in various chronic conditions. Methods: Bone quality was evaluated using a calcaneal QUS device. Auxological parameters, nutritional intakes, and plasma levels of key bone biomarkers were also registered. The population was divided into four groups: PKU patients under diet therapy and HPA patients on a free diet, both divided into receiving or not receiving single vitamin D supplementation. Results: All HPA/PKU patients had median bone quality index (BQI) Z- and T-score values lower than −1, with slightly better values in HPA children and PKU-supplemented adults. Dietary vitamin D intake in PKU patients was significantly higher than in HPA subjects (p < 0.001), due to protein substitute supplementation. However, plasma 25(OH) vitamin D levels, although increased compared to baseline, were still overlapping among groups (p = 0.845) after supplementation. Approximately a quarter of both pediatric and adult non-supplemented PKU patients had Z-score and T-score levels below −2, and this percentage decreased with vitamin D supplementation in all groups. In PKU-supplemented patients, the Broadband Ultrasound Attenuation (BUA) was significantly higher than in the other groups (p = 0.040). Conclusions: The improvement in BUA may represent preliminary evidence of the effect of vitamin D on bone architecture, which could encourage this supplementation to prevent the worsening of bone structure and reduce the risk of fractures.

Introduction: The psychosocial impact of living with an Inherited Metabolic Disorder (IMD) is becoming increasingly relevant and can have a significant impact on planning the future, conditioning the reproductive decisions made during adolescence and young adulthood. The aim of this paper is to explore thoughts about partner choices, parenthood and pregnancy among adolescents and young adults affected by IMDs. Methods: A cross-sectional study was performed. A sample of 23 patients affected by a range of IMDs were interviewed. Twenty-two questions were provided, distinguished into four main themes: partners, parenthood, pregnancy and need for information. Results: More than half of participants (57%) reported insecurities about relationships and declared that they were single for this reason, with most (70%) having a hope of having children in the future, although with the awareness and fear that they could also be affected. Almost all females (90%) consider themselves able to carry a pregnancy in a way similar to other women. There was the common need for more information about their potential fertility and parenthood linked to their condition. Conclusion: Being diagnosed with an IMD can influence personal decisions regarding relationships and reproduction. The early identification of issues in these domains may enhance referrals for personalized interventions and build more focused support programmes.

Background: Apulia and neighboring Southern Italian regions present a complex genetic stratification shaped by historical migrations. Phenylketonuria (PKU), caused by PAH mutations, serves as an excellent model for molecular epidemiology. This study maps the geographical distribution of PAH variants in a large Southern Italian cohort, evaluating their correlation with clinical phenotypes and long-term Body Mass Index (BMI). Methods: A retrospective cohort study was conducted on 344 patients followed for at least 10 years. Genetic characterization evolved from Sanger to Next-Generation Sequencing, and patients were stratified into micro-geographic clusters. Results: The genetic landscape was dominated by three ancestral variants (c.1208C>T, c.1066-11G>A, c.898G>T), accounting for 58% of the allelic pool. Significant micro-geographic polarization was observed: c.1222C>T clustered in Central-Northern Apulia, mirroring historical Norman-Swabian migration, whereas c.441+5G>T enriched in Southern Apulia. At final follow-up, classic PKU patients exhibited a four-fold increased risk of obesity, driven by severe null alleles enforcing lifelong dependency on engineered low-protein foods. Conclusion:PAH mutational stratification acts as a contemporary reflection of historical migratory maps. Incorporating regional and genotypic mapping provides a precision medicine framework to anticipate phenotype severity, optimize therapeutic management, and tailor long-term metabolic risk monitoring.

Background: Apulia and neighbouring Southern Italian regions present a complex genetic stratification shaped by historical migrations. Phenylketonuria (PKU), caused by PAH mutations, serves as an excellent model for molecular epidemiology. This study maps the geographical distribution of PAH variants in a large Southern Italian cohort, evaluating their correlation with clinical phenotypes and long-term Body Mass Index (BMI). Methods: A retrospective cohort study was conducted on 344 patients followed for at least 10 years. Genetic characterization evolved from Sanger to Next-Generation Sequencing, and patients were stratified into micro-geographic clusters. Results: The genetic landscape was dominated by three ancestral variants (c.1208C>T, c.1066-11G>A, c.898G>T), accounting for 58% of the allelic pool. Significant micro-geographic polarization was observed: c.1222C>T clustered in Central–Northern Apulia, mirroring historical Norman-Swabian migration, whereas c.441+5G>T enriched in Southern Apulia. At final follow-up, classic PKU adult patients exhibited a four-fold increased risk of obesity (p < 0.05), driven by severe null alleles that necessitate a lifelong dependency on engineered low-protein foods. Conclusions: PAH mutational stratification serves as a contemporary reflection of historical migratory maps. Incorporating regional and genotypic mapping provides a precision medicine framework to anticipate phenotype severity, optimize therapeutic management, and tailor long-term obesity risk monitoring.