[Newborn screening in France: news and perspectives]

Newborn screening is a major public health concern. In France, it was established in 1972 with systematic screening for phenylketonuria. Subsequently, other screenings, including congenital hypothyroidism, congenital adrenal hyperplasia, cystic fibrosis, and sickle cell disease, were added. The introduction of tandem mass spectrometry in screening laboratories in 2020 enabled the inclusion of eight additional inherited metabolic diseases: aminoacidopathies (tyrosinemia type I, maple syrup urine disease, and homocystinuria), organic acidurias (isovaleric and glutaric type I acidurias), and disorders of fatty acid metabolism (MCADD, long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD), and primary carnitine deficiency). We briefly present these newly added diseases, of which public awareness is still incomplete.

Result of a Pilot External Quality Assessment Scheme for Clinical Diagnosis of Inherited Metabolic Disorders in China

BACKGROUND

We aimed to evaluate the diagnostic capabilities of Chinese laboratories for inherited metabolic disorders (IMDs) using gas chromatography-mass spectrometry (GC-MS) on urine samples. Meanwhile, based on the result of the pilot external quality assessment (EQA) scheme, we hope to establish a standardized and reliable procedure for future EQA practice.

METHODS

We recruited laboratories that participated in the EQA of quantitative analysis of urinary organic acids with GC-MS before joining the surveys. In each survey, a set of five real urine samples was distributed to each participant. The participants should analyze the sample by GC-MS and report the "analytical result", "the most likely diagnosis", and "recommendation for further tests" to the NCCL before the deadline.

RESULTS

A total of 21 laboratories participated in the scheme. The pass rates were 94.4% in 2020 and 89.5% in 2021. For all eight IMDs tested, the analytical proficiency rates ranged from 84.7% - 100%, and the interpretational performance rate ranged from 88.2% - 97.0%. The performance on hyperphenylalaninemia (HPA), 3-methylcrotonyl-CoA carboxylase deficiency (MCCD), and ethylmalonic encephalopathy (EE) samples were not satisfactory.

CONCLUSIONS

In general, the participants of this pilot EQA scheme are equipped with the basic capability for qualitative organic acid analysis and interpretation of the results. Limited by the small size of laboratories and samples involved, this activity could not fully reflect the state of clinical practice of Chinese laboratories. NCCL will improve the EQA scheme and implement more EQA activities in the future.

Glycomacropeptide-Based Protein Substitutes for Children with Phenylketonuria in Italy: A Nutritional Comparison

Advancements in food science technology have allowed the development of new products for the therapeutic management of inherited metabolic diseases such as phenylketonuria (PKU). Glycomacropeptide (GMP), a peptide derived from casein, is naturally low in phenylalanine (Phe) and, thus, adequate for protein substitutes (PSs) for the management of PKU in children. This review aims primarily to analyse the differences in the nutritional composition of GMP-based protein substitutes in different formulations (ready to drink, powdered, and bars), and secondarily to assess the quality of these products, comparing their nutritional composition with that of standard amino acid (L-AA) mixtures. Thirty-five GMP-based PSs produced by six different companies were included in this review: twenty-one powdered PSs, eight ready to drink, and six bars. The analysis revealed great heterogeneity not only among the different formulations (powdered, ready to drink, and bars) but also within the same group, in terms of energy content and nutritional composition. GMP-based PSs were shown to have higher contents of sugars and saturated fatty acids compared to L-AA PSs, especially in ready-to-drink formulations and bars. The latter also provided the highest amounts of energy among the GMP-based products. This finding may be related to a higher risk of developing overweight and obesity. The greater palatability of these GMP-based PSs, combined with improved nutritional quality, could not only improve adherence to diet therapy but also reduce the incidence of obesity-related comorbidities in PKU.

Mechanisms underlying the efficacy and limitation of dopa and tetrahydrobiopterin therapies for the deficiency of GTP cyclohydrolase 1 revealed in a novel mouse model

Dopa and tetrahydrobiopterin (BH4) supplementation are recommended therapies for the dopa-responsive dystonia caused by GTP cyclohydrolase 1 (GCH1, also known as GTPCH) deficits. However, the efficacy and mechanisms of these therapies have not been intensively studied yet. In this study, we tested the efficacy of dopa and BH4 therapies by using a novel GTPCH deficiency mouse model, Gch1KI/KI, which manifested infancy-onset motor deficits and growth retardation similar to the patients. First, dopa supplementation supported Gch1KI/KI mouse survival to adulthood, but residual motor deficits and dwarfism remained. Interestingly, RNAseq analysis indicated that while the genes participating in BH4 biosynthesis and regeneration were significantly increased in the liver, no significant changes were observed in the brain. Second, BH4 supplementation alone restored the growth of Gch1KI/KI pups only in early postnatal developmental stage. High doses of BH4 supplementation indeed restored the total brain BH4 levels, but brain dopamine deficiency remained. While total brain TH levels were relatively increased in the BH4 treated Gch1KI/KI mice, the TH in the striatum were still almost undetectable, suggesting differential BH4 requirements among brain regions. Last, the growth of Gch1KI/KI mice under combined therapy outperformed dopa or BH4 therapy alone. Notably, dopamine was abnormally high in more than half, but not all, of the treated Gch1KI/KI mice, suggesting the existence of variable synergetic effects of dopa and BH4 supplementation. Our results provide not only experimental evidence but also novel mechanistic insights into the efficacy and limitations of dopa and BH4 therapies for GTPCH deficiency.

Evaluating change in diet with pegvaliase treatment in adults with phenylketonuria: Analysis of phase 3 clinical trial data

Phenylketonuria (PKU), a genetic disorder characterized by phenylalanine hydroxylase (PAH) deficiency and phenylalanine (Phe) accumulation, is primarily managed with a protein-restricted diet and PKU-specific medical foods. Pegvaliase is an enzyme substitution therapy approved for individuals with PKU and uncontrolled blood Phe concentrations (>600 μmol/L) despite prior management. This analysis assessed the effect of pegvaliase on dietary intake using data from the Phase 3 PRISM-1 (NCT01819727), PRISM-2 (NCT01889862), and 165-304 (NCT03694353) clinical trials. Participants (N = 250) had a baseline diet assessment, blood Phe ≥600 μmol/L, and had discontinued sapropterin; they were not required to follow a Phe-restricted diet. Outcomes were analyzed by baseline dietary group, categorized as >75%, some (>0% but ≤75%), or no protein intake from medical food. At baseline, mean age was 29.1 years, 49.2% were female, mean body mass index was 28.4 kg/m2, and mean blood Phe was 1237.0 μmol/L. Total protein intake was stable up to 48 months for all 3 baseline dietary groups. Over this time, intact protein intake increased in all groups, and medical protein intake decreased in those who consumed any medical protein at baseline. Of participants consuming some or >75% medical protein at baseline, 49.1% and 34.1% were consuming no medical protein at last assessment, respectively. Following a first hypophenylalaninemia (HypoPhe; 2 consecutive blood Phe measurements <30 μmol/L) event, consumption of medical protein decreased and consumption of intact protein increased. Substantial and sustained Phe reductions were achieved in all 3 baseline dietary groups. The probability of achieving sustained Phe response (SPR) at ≤600 μmol/L was significantly greater for participants consuming medical protein versus no medical protein in an unadjusted analysis, but no statistically significant difference between groups was observed for probability of achieving SPR ≤360 or SPR ≤120 μmol/L. Participants with alopecia (n = 49) had longer pegvaliase treatment durations, reached HypoPhe sooner, and spent longer in HypoPhe than those who did not have alopecia. Most (87.8%) had an identifiable blood Phe drop before their first alopecia episode, and 51.0% (n = 21/41) of first alopecia episodes with known duration resolved before the end of the HypoPhe episode. In conclusion, pegvaliase treatment allowed adults with PKU to lower their blood Phe, reduce their reliance on medical protein, and increase their intact and total protein intake. Results also suggest that HypoPhe does not increase the risk of protein malnutrition in adults with PKU receiving pegvaliase.

Outcomes in 14 live births resulting from Pegvaliase-treated pregnancies in PKU-affected females

BACKGROUND

Adults with PKU have difficulty maintaining plasma phenylalanine (Phe) in the range that is safe for neurologic function. Elevated plasma Phe is a risk factor for congenital anomalies and developmental delay in offspring resulting from pregnancies with poor Phe control in women with PKU. Enzyme supplementation with pegvaliase allows adults with PKU to eat an unrestricted diet and have plasma Phe levels in a safe range for pregnancy but pegvaliase has not been approved for use in pregnant females with PKU. We report the results of chart review of 14 living offspring of females affected with PKU who were responsive to pegvaliase and chose to remain on pegvaliase throughout their pregnancy.

METHODS

Fourteen pregnancies (one triplet pregnancy) and their offspring were identified at eight PKU treatment centers and medical records from pregnancy and birth were submitted for this study. Institutional Review Board approval was obtained. Responses to a dataset were provided to a single center and analyzed.

RESULTS

Six females and eight males were born without congenital anomalies and all offspring had normal growth parameters. While mothers had preexisting comorbidities, no additional comorbidities were reported in the offspring. Four of eleven infants (excluding triplet pregnancies) were delivered preterm (36%), a higher rate than the general population (12%). A single first trimester (eight weeks) miscarriage in a 40y was not counted in this cohort of 14 live born infants.

CONCLUSION

This retrospective study suggests that pegvaliase is effective at maintaining safe maternal blood Phe levels during pregnancy without deleterious effects on mother or child. A tendency toward premature birth (4/11; 36%) is higher than expected.

The COVID-19 pandemic impact on continuity of care provision on rare brain diseases and on ataxias, dystonia and PKU. A scoping review

One of the most relevant challenges for healthcare providers during the COVID- 19 pandemic has been assuring the continuity of care to patients with complex health needs such as people living with rare diseases (RDs). The COVID-19 pandemic accelerated the healthcare sector's digital transformation agenda. The delivery of telemedicine services instead of many face-to-face procedures has been expanded and, many healthcare services not directly related to COVID-19 treatments shifted online remotely. Many hospitals, specialist centres, patients and families started to use telemedicine because they were forced to. This trend could directly represent a good practice on how care services could be organized and continuity of care could be ensured for patients. If done properly, it could boast improved patient outcomes and become a post COVID-19 major shift in the care paradigm. There is a fragmented stakeholders spectrum, as many questions arise on: how is e-health interacting with 'traditional' healthcare providers; about the role of the European Reference Networks (ERNs); if remote care can retain a human touch and stay patient centric. The manuscript is one of the results of the European Brain Council (EBC) Value of Treatment research project on rare brain disorders focusing on progressive ataxias, dystonia and phenylketonuria with the support of Academic Partners and in collaboration with European Reference Networks (ERNs) experts, applying empirical evidence from different European countries. The main purpose of this work is to investigate the impact of the COVID-19 pandemic on the continuity of care for ataxias, dystonia and phenylketonuria (PKU) in Europe. The analysis carried out makes it possible to highlight the critical points encountered and to learn from the best experiences. Here, we propose a scoping review that investigates this topic, focusing on continuity of care and novel methods (e.g., digital approaches) used to reduce the care disruption. This scoping review was designed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews (PRISMA-ScR) standards. This work showed that the implementation of telemedicine services was the main measure that healthcare providers (HCPs) put in place and adopted for mitigating the effects of disruption or discontinuity of the healthcare services of people with rare neurological diseases and with neurometabolic disorders in Europe.

Phenylketonuria from the perspectives of patients in Türkiye

BACKGROUND

The present study aimed to determine the problems, unmet needs and expectations of phenylketonuria (PKU) patients in Türkiye regarding follow-up and treatment in order to provide data for future planning and implementations on PKU.

METHODS

The study included patients diagnosed with PKU and/or their parents. They were informed about the study via phone calls and their verbal consents were obtained. Questions in the data collection forms, which were established separately for pediatric, adolescent, and adult age groups, were applied during the interviews and the answers were recorded.

RESULTS

Among 182 classical PKU patients, 66 (36.3%) were in the pediatric group (0-12 years old), 44 (24.2%) were in the adolescent group (13-19 years old), and 72 (39.5%) were in the adult group (≥ 20 years old). In all patient groups, phenylalanine-restricted diet and medical nutrition products were the main options for treatment. The median of the last measured blood phenylalanine concentration (patient-reported) was 290 µmol/L, 425 µmol/L, and 750 µmol/L in the pediatric, adolescent, and adult groups, respectively. The frequency of blood testing for serum phenylalanine level according to the age groups was appropriate in nearly half of the patients. While the majority of the patients have been visiting the metabolism center they have been diagnosed with PKU for control, considerable proportion of the patients would like to change the center or the doctor they visit for control if they could. It was determined that nearly half of the patients had trouble in accessing the metabolism center. Treatment options' being limited and expensive were the major problems. The main requests of the patients and patient relatives included easier access to the metabolism centers and more options for treatment and diet.

CONCLUSIONS

Access to the services should be easier to improve the patients' follow-up and treatment. There is need for low-cost, easily applicable, and accessible nutrition products and effective novel pharmacological agents. Focusing on these issues in health policies by providing pedagogic/psychological support, establishing support programs also comprising the families, and increasing the awareness activities were the key outcomes.

Dietary intake in individuals with phenylketonuria: an integrative review

Introduction

Introduction: the dietary intake of individuals with phenylketonuria (PKU) may vary widely according to different cultural eating habits, lifestyle, access to multidisciplinary team, and metabolic formulas available. Thus, knowing the dietary intake of this population makes it possible to tailor nutritional treatment strategies to impact their health. Objective: to analyze the evidence on the dietary intake of individuals with PKU. Methods: an integrative literature review was conducted on the dietary intake of individuals with PKU in the databases PUBMED, BIREME and Science Direct. Original articles that addressed the energy and macronutrient food intake of children, adolescents and/or adults with PKU were included in the study, without time restriction, in any language. A total of 384 articles were found and 27 articles were selected and analyzed. Results: evidence about the nutritional composition of their diet showed that individuals with PKU consume between 1160-2721 kcal of energy -7.2-17.4 % (32.4-76.9 g) of energy as protein, 45.9-69.2 % of energy as carbohydrates, 16.6-39 % of energy as lipids- and between 7.6 and 20 g of fiber. Conclusion: most individuals with PKU have low energy, protein and fiber intake, adequate lipid intake, and high carbohydrate intake. Metabolic control of the disease is still a challenge in all countries. Nutritional strategies to improve dietary nutritional composition and phenylalanine blood levels in individuals with PKU remain an urgent issue.

The investigation of serum phenylalanine levels based on infant feeding method: a cross-sectional study of children less than two years old with phenylketonuria (PKU)

BACKGROUND

Clinical advice may suggest discontinuing breastfeeding after the diagnosis of phenylketonuria in infants as the only effective way to monitor the newborn's intake and accurate measurement of phenylalanine (Phe). This study aims to investigate the prevalence and duration of breastfeeding, as well as its effect on serum Phe levels in infants with phenylketonuria at Education and Therapy Medical Center, Be'sat Hospital, Iran.

METHODS

We conducted a cross-sectional study of 34 children under two years old diagnosed with phenylketonuria between September 2018 and December 2022. Infants were categorized as breastfed and non-breastfed (bottle-fed) based on their feeding method after diagnosis. Data on age at diagnosis, medical records, demographic information, and anthropometric indices were collected, and infants with incomplete data or mixed feeding (formula + breast milk) were excluded from the study.

RESULTS

Of 94 infants managed in our hospital, 34 had complete medical records. Among the all patients 13 (38%) continued to be breastfed combined with phenylalanine-free amino acid-based protein substitute, while 21 (62%) were did not receive breast milk. The mean duration of breastfeeding was 2.57 ± 0.59 (1-3) months. The mean age at diagnosis was 22.6 ± 18.4 days. Phenylalanine concentrations at diagnosis were mean 10, SD 5.44; range 4-24 mg/dL [0.22-1.33 μmol/L] in the breastfed group and mean 14.3, SD 10.2; range 5-37 mg/dL [0.27-2.05 μmol/L] in the non-breastfed group.Non-breastfed infants had lower serum Phe levels than breastfed infants: mean 3.76, SD 2.10; range 1-7 mg/dL [0.05-0.38 μmol/L] and mean 4.89, SD 3.68; range 2-19 mg/dL [0.11-1.05 μmol/L], respectively, although not statistically significant [(t (34) = 118.0, P = 0.51]. Also we found no significant associations in body measurements for weight, height, and head circumference at birth and final assessment.

CONCLUSIONS

In conclusion, during treatment, there were no statistically significant associations between breastfeeding and serum Phe levels with growth in children with phenylketonuria.

Odimet®: A Pioneering Tele-Health Tool to Empower Dietary Treatment and the Acute Management of Inborn Errors of Metabolism-An Assessment of Its Effectiveness during the COVID Pandemic

Strict adherence to a diet is an essential pillar of long-term treatment for many inborn errors of metabolism (IEMs). Tools that educate patients about dietary management can positively condition adherence and prevent morbidity. We designed a free online dietary calculation program (Odimet®, version 2.1.) for IEMs patients in 2008, updated in 2022, that provides detailed information on the content of amino acids, protein, lipids, carbohydrates, vitamins and minerals in >3000 food products, including specific medical foods for IEM. We analyzed the statistics on visits to Odimet® to evaluate its usefulness for long-term dietary management during a 5-year period focusing on three periods: pre-pandemic (15 March 2018-14 March 2020); pandemic 1 (15 March 2020-14 March 2021); and pandemic 2 period (15 March 2021-15 March 2023), in 120 patients with the following distribution: 84 patients with phenylketonuria (PKU); 12 with maple syrup urine disease (MSUD); 11 with urea cycle disorders (UCDs); and 13 with classical galactosemia. The evolutionary levels of their specific metabolic markers were evaluated, showing that globally, both pediatric and adult patients maintain a good metabolic control, even during a pandemic (median levels of phenylalanine in pediatric PKU patients 213.4 µmol/L and 482.3 µmol/L in adults; of leucine in MSUD patients: 144.2 µmol/L; of glutamine in UCDs: 726.8 µmol/L; and of galactose 1-phosphate levels in galactosemia: 0.08 µmol/L). The proportion of patients using Odimet® ranges from 78-100%. An increase in the number of diets being calculated was observed during COVID-19 pandemic. Currently, 14,825 products have been introduced (3094 from the general database, and 11,731 added by users to their own profiles). In 2023 63 emergency dietary adjustments in the studied intoxication-type pathologies were calculated in Odimet®. Our results suggest that its regular use contributes to maintaining metabolic stability in IEMs patients, allowing them to adapt their menus to their lifestyle, and represents a powerful complementary tele-health tool which can be used to perform remote real-time dietary follow-up.

Triple Genetic Diagnosis in a Patient with Late-Onset Leukodystrophy and Mild Intellectual Disability

We describe the complex case of a 44-year-old man with polycystic kidney disease, mild cognitive impairment, and tremors in the upper limbs. Brain MRI showed lesions compatible with leukodystrophy. The diagnostic process, which included clinical exome sequencing (CES) and chromosomal microarray analysis (CMA), revealed a triple diagnosis: autosomal dominant polycystic kidney disease (ADPKD) due to a pathogenic variant, c.2152C>T-p.(Gln718Ter), in the PKD1 gene; late-onset phenylketonuria due to the presence of two missense variants, c.842C>T-p.(Pro281Leu) and c.143T>C-p.(Leu48Ser) in the PAH gene; and a 915 Kb duplication on chromosome 15. Few patients with multiple concurrent genetic diagnoses are reported in the literature; in this ADPKD patient, genome-wide analysis allowed for the diagnosis of adult-onset phenylketonuria (which would have otherwise gone unnoticed) and a 15q11.2 duplication responsible for cognitive and behavioral impairment with incomplete penetrance. This case underlines the importance of clinical genetics for interpreting complex results obtained by genome-wide techniques, and for diagnosing concurrent late-onset monogenic conditions.

Progress of newborn screening in China

Newborn screening (NBS) plays a significant role in reducing the risk of birth defects. NBS in China began in the early 1980s. Under the protection of laws and regulations and the leadership of the national health administration, approved screening centers in public hospitals took the responsibility for publicity, screening, diagnosis, treatment, follow-up and management of birth defects. As of 2022, 31 provinces (autonomous regions and municipalities directly under the central government) have carried out NBS for phenylketonuria, congenital hypothyroidism, and hearing loss, 23 provinces have carried out screening for glucose-6-phosphate dehydrogenase (with a screening rate of 89.24%), and 24 provinces have carried out screening for congenital adrenal cortical hyperplasia (91.45% screening rate). Over the past four decades, screening techniques have evolved from bacterial inhibition, fluorescence analysis, and tandem mass spectrometry for the detection of biochemical markers to genetic testing, which has greatly contributed to the expansion of the types of diseases screened for. The combined use of metabolomics and genomics is currently being explored. Effective management and rigorous quality control of NBS are prerequisites for improving the quality and ensuring the accuracy of screening. The Quality Management System for Newborn Screening System Network (QMS-NBS), established by the National Center for Clinical Laboratories, covers all screening centers and related blood collection agencies. The operation of the QMS-NBS allows the quality and performance of screening to be transparent and measurable, ensuring the quality and efficiency of screening. This article provides an overview of the history of NBS, especially the evolution of policies for the NBS in China, the construction of screening institutions, the number of newborns screened, the incidence rates of screened diseases, the changes in screening technology, the expansion of new diseases screened for, and the quality control of NBS. Overall, the progress in NBS in China has not only benefited from the development and standardization at the technological level, but also benefited from the construction of policies, regulations and ethics.

Parent knowledge regarding food selection for children with PKU: Results of a survey in the United States

OBJECTIVES

Dietary treatment is the main therapy for most patients with phenylketonuria (PKU). Parental knowledge regarding food selection is crucial to ensure adequate metabolic control and brain development during childhood and to promote lifelong adherence and healthy dietary behavior in the offspring. The aims of this study were to assess whether parental or caregiver knowledge regarding nutritional selection for children with PKU is in accordance with medical recommendations and to evaluate factors that influence their level of knowledge.

METHODS

This was a cross-sectional observational study. An online or paper survey (N = 178) was distributed throughout the United States. The survey included a validated food selection questionnaire to assess whether the respondent adequately identified foods that require certain restrictions versus foods that can be consumed freely by an individual with PKU.

RESULTS

General knowledge of food selection among the caregivers was very high or high in nearly 60% (60-98th score percentile). Participants with the lowest scores in general knowledge of the PKU diet (quartile 1) were more likely to label allowed foods incorrectly. Respondents with the highest scores (quartile 4) were more likely to label limited foods correctly but incorrectly label allowed items.

CONCLUSION

Knowledge of restricted foods is important to avoid poor metabolic control, but knowledge of allowed foods can be just as important to allow for a diet that is diverse, palatable, and nutritionally balanced.

Natural Protein Intake in Children with Phenylketonuria: Prescription vs. Actual Intakes

In phenylketonuria (PKU), an important component of the UK dietary management system is a 50 mg phenylalanine (Phe)/1 g protein exchange system used to allocate the Phe/natural protein intakes according to individual patient tolerance. Any foods containing protein ≤ 0.5 g/100 g or fruits/vegetables containing Phe ≤ 75 mg/100 g are allowed without measurement or limit. In children with PKU, we aimed to assess the difference between the prescribed natural protein intake and their actual consumed intake, and to calculate the natural protein/Phe intake from foods given without measurement or restriction. Over a 6-month duration, three one-day diet diaries were collected every month by caregivers of children with PKU at the beginning of a follow-up study. Dietary intakes of Phe, as well as natural and total protein intakes, were calculated using Nutritics® (v5.09). Weekly blood Phe spots were collected by caregivers. The target blood Phe level was ≤360 μmol/L for ages up to 12 years and ≤600 μmol/L for ages ≥12 years. Sixteen early treated children (69% females) with PKU were recruited. The median age was 11 years (range: 9-13), and most had classical PKU (n = 14/16). A median of 18 (range 12-18) one-day diaries and 22 blood spots were analysed for each subject over 6 months. The median prescribed natural protein was 6 g/day (range: 3-27), but when calculated, the actual median intake from all foods consumed was 10 g/day (range: 4-37). The median prescribed Phe was 300 mg/day (range: 150-1350), but the actual median intake was 500 mg/day (range: 200-1850). The median difference between the prescribed and actual natural protein daily intakes was +4 g/day (range: -2.5 to +11.5), with a median percentage increase of 40% for natural protein/Phe intake (p < 0.001). The median blood Phe level was 250 μmol/L (range 20-750), with 91% of blood Phe levels within the target range. Only one patient (11 years) had less than 75% of their blood Phe levels within the target range. The UK Phe exchange system provides flexibility in the dietary management of PKU. With this method, the actual natural protein intake was 167% higher than the prescribed amount. Although this led to a variable daily protein intake, the majority of children (n = 15/16) experienced no deterioration in their metabolic control.

Total Protein Intake in Patients with PKU: Adequacy Evaluation According to the European PKU Guidelines from 2017

In PKU, the protein requirements are contentious. In 2018, we evaluated the protein intake in patients with PKU. Ninety-nine early treated patients aged 19.3 ± 8.2 years (54% males) were studied. A total of 24 had hyperphenylalaninemia (HPA), 48 mild and 27 classical PKU. All had an annual nutritional status evaluation. A total of 83% were on diet therapy only, and 17% were on diet with tetrahydrobiopterin therapy. Anthropometry, metabolic control and nutritional intake [total protein (TP, g/kg), natural protein (NP, g/kg), protein equivalent from protein substitutes (PE, g/kg)] were collected. TP adequacy (TPA) was calculated as a % of WHO (2007) safe levels of protein intake. Results were compared with the European PKU Guidelines (EPG). The median % contribution NP of TP intake was 53% [31-100]. Most patients (78%) had a TP intake above the EPG recommendations. The median TPA was 171% [146-203], with 79% [51-165] from NP and 84% [0-109] from PE. A TPA of 100-140% was observed in 16 (16%) patients. Only n = 6 (6%) patients had a TPA < 100%. These results emphasize the heterogeneity of PKU. More research is needed to understand the necessity of a single protein recommendation for all, as a 'one-size-fits-all' solution might not be appropriate.

Late-onset symptomatic hyperprolactinemia in 6-pyruvoyl-tetrahydropterin synthase deficiency

BACKGROUND

Tetrahydrobiopterin (BH4) deficiency caused by 6-pyruvoyl-tetrahydropterin synthase (PTPS) deficiency is a rare disorder that is one of the major causes of hyperphenylalaninemia in Taiwan.

METHODS

In this study, we reviewed the clinical courses of 12 adolescent and adult patients (7 females and 5 males) with PTPS deficiency.

RESULTS

The patients were treated shortly after diagnosis through newborn screening with a combination of BH4, levodopa/carbidopa, and 5-OH-tryptophan. Their plasma phenylalanine and tyrosine levels were well controlled, and their prolactin levels were also decreased after treatment. However, their prolactin levels gradually rose as they grew into puberty, and at a current age of 27.5 [interquartile range (IQR 7.9)] years, five of the 12 patients had either highly elevated prolactin levels (> 100 ng/mL in one male patient, normal reference values, male < 11 ng/mL, female < 17 ng/mL) or symptoms, including irregular menstruation, amenorrhea, and breast swelling (in four female patients). The dosage of levodopa in these five patients (14.3 (IQR 3.0) mg/kg/day) was slightly higher than that in the other patients (p = 0.05). Magnetic resonance imaging studies did not reveal an increase in the size of the anterior pituitary gland, although a Rathke cleft cyst was found in one patient. Two patients received cabergoline treatment, which promptly lowered prolactin levels and relieved symptoms.

CONCLUSIONS

Hyperprolactinemia is common in female patients with PTPS deficiency, especially after puberty. A long-acting dopamine agonist, such as cabergoline, may be a necessary adjunctive treatment for most patients with BH4 deficiency.

Possible role of tryptophan metabolism along the microbiota-gut-brain axis on cognitive & behavioral aspects in Phenylketonuria

Cognitive and psychiatric disorders are well documented across the lifetime of patients with inborn errors of metabolism (IEMs). Gut microbiota impacts behavior and cognitive functions through the gut-brain axis (GBA). According to recent research, a broad spectrum of GBA disorders may be influenced by a perturbed Tryptophan (Trp) metabolism and are associated with alterations in composition or function of the gut microbiota. Furthermore, early-life diets may influence children's neurodevelopment and cognitive deficits in adulthood. In Phenylketonuria (PKU), since the main therapeutic intervention is based on a life-long restrictive diet, important alterations of gut microbiota have been observed. Studies on PKU highlight the impact of alterations of gut microbiota on the central nervous system (CNS), also investigating the involvement of metabolic pathways, such as Trp and kynurenine (KYN) metabolisms, involved in numerous neurodegenerative disorders. An alteration of Trp metabolism with an imbalance of the KYN pathway towards the production of neurotoxic metabolites implicated in numerous neurodegenerative and inflammatory diseases has been observed in PKU patients supplemented with Phe-free amino acid medical foods (AA-MF). The present review investigates the possible link between gut microbiota and the brain in IEMs, focusing on Trp metabolism in PKU. Considering the evidence collected, cognitive and behavioral well-being should always be monitored in routine IEMs clinical management. Further studies are required to evaluate the possible impact of Trp metabolism, through gut microbiota, on cognitive and behavioral functions in IEMs, to identify innovative dietetic strategies and improve quality of life and mental health of these patients.

Actions speak louder than words: Home visits and its effect on dietary adherence in patients with phenylketonuria

AIM

Phenylketonuria (PKU) is an inherited metabolic disorder in which accumulation of phenylalanine (Phe) leads to poor neurological outcomes without treatment. Dietary therapy is the main treatment and nonadherence is associated with elevated blood Phe levels and correspondingly poor neuropsychiatric outcomes. This study aimed to examine the effect of home visits on blood Phe levels in PKU patients.

METHODS

Sixty-five paediatric PKU patients who were on low-phenylalanine diet were visited monthly at home for 6 months. At each visit, dietary education was provided, patients' height and weight were measured and blood samples were collected.

RESULTS

Twenty-eight (43.1%) patients had classic PKU and 37 (56.9%) had moderate PKU. Blood Phe levels decreased statistically significant at first, second, fifth, and sixth months compared with screening visit. Blood Phe levels in moderate PKU patients decreased significantly at the last visit unlike classic PKU patients. A significant decrease in blood Phe levels was observed in patients older than 10 years. Anthropometric parameters improved.

CONCLUSIONS

Dietary nonadherence is the main treatment failure in PKU. Home visits for education are a promising way to improve treatment outcomes by providing quality education, better assessment, and correction of mistakes but they should be ongoing and supported by different interventions that address patients' special needs.

Adult PKU Clinics in the UK-Users' Experiences and Perspectives

Adults with PKU require life-long management, and ideally, their care should be in a specialised adult metabolic clinic. Their outcomes and co-morbidities have received much attention, but data are lacking on their experience, satisfaction and expectations about the care they receive. This survey reports the experiences and care adults with PKU receive from specialist metabolic clinics in the UK. The online survey developed by the UK NSPKU (National Society for Phenylketonuria), was placed on the NSPKU website from February 2021 to December 2022, and was completed by adults with PKU (≥18 years) or their carers/family members. Sixty-five adult PKU patients and 9 caregivers of adult patients completed the questionnaire (63% female in total). Only 32% of respondents were following a Phe-restricted diet with protein substitute intake as prescribed; the rest were partially adherent or not on dietary restrictions. Nineteen per cent (n = 14/74) had not been reviewed in clinic for two years. Half of the respondents (50%) described their experience in adult clinics as "good". Half of the patients were unable to contact their dietitians with questions or concerns, and only 24% considered that they received adequate support. Clinic reviews usually included anthropometric (82%) and dietary assessments (64%), discussion on management of PKU in daily life (78%) and a blood test (71%). Eighty-eight per cent reported they had at least one neurocognitive, mental health or behavioural co-morbidity but less than half of the patients reported an assessment on their neurocognitive functioning or mental health issues. Adult male patients appeared to have less detailed clinic review than females. Less than half (44%) of the respondents reported that they performed a blood spot for blood Phe at least monthly, but only 32% considered they had been informed about the risk of high Phe levels in adulthood. Although time, cost and stress related to travelling were barriers to a face-to-face review, more than 40% of patients had concerns about remote appointments. The frequency and extent of monitoring of adults with PKU, attending specialist adult services, were less than those specified by the PKU European guidelines. The care of women of reproductive age is prioritised over men. Adult metabolic health services require further attention, development and resources to provide a high standard and equitable service to patients with PKU.

Accuracy of equations for estimating resting energy expenditure in children and adolescents living with phenylketonuria

BACKGROUND

Measuring resting energy expenditure (REE) in individuals living with phenylketonuria (PKU) using indirect calorimetry (IC) is unusual in healthcare facilities because it requires specific protocols and expensive equipment. Considering that determining REE is crucial for devising nutritional strategies for the management of PKU, the aim of this study was to identify the predictive equations that provide the best estimates of REE in children and adolescents living with PKU and to propose a predictive equation for determining REE in this population.

METHODS

An REE concordance study was conducted with children and adolescents living with PKU. Anthropometric and body composition assessments using bioimpedance and REE assessment using IC were performed. The results were compared to 29 predictive equations.

RESULTS

Fifty-four children and adolescents were evaluated. The REE obtained using IC differed from all estimated REE, except Henry's equation for male children (p = 0.058). Only this equation showed good agreement (0.900) with IC. Eight variables were associated with the REE obtained using IC with emphasis on fat-free mass (kg) (r = 0.786), weight (r = 0.775), height (r = 0.759) and blood phenylalanine (r = 0.503). With these variables, three REE equations were suggested, with R2  = 0.660, 0.635 and 0.618, respectively, and the third equation, which involves weight and height, showed adequate sample size for a statistical power of 0.942.

CONCLUSION

Most equations, not specific for individuals living with PKU, overestimate the REE of this population. We propose a predictive equation for assessing REE for children and adolescents living with PKU to be used in settings where IC is not available.

Breast feeding in infants diagnosed with phenylketonuria (PKU): a scoping review

BACKGROUND

Phenylketonuria (PKU) is the most common inherited disease of amino acid metabolism, characterised by elevated levels of phenylalanine (Phe). There is a lack of infant feeding guidance for those with PKU. From birth to 6 months of age, breast feeding is the optimal nutrition for an infant and continuing breast feeding for infants with PKU is recommended by European guidelines. However, human breast milk contains Phe in varying quantities, and therefore, the effects breast feeding might have on infants with PKU needs careful consideration.

AIM

To assess the effects of breast feeding (exclusive or partial) compared with low-Phe formula feeding in infants diagnosed with PKU, on blood Phe levels, growth and neurodevelopmental scores.

METHODS

The Cochrane Inborn Errors of Metabolism Trials Register, MEDLINE and Embase were searched (date of latest search: 9 August 2022). Studies were included if they looked at the effects of breast feeding in infants diagnosed with PKU compared with formula feeding. Predetermined outcomes included blood Phe levels, growth in the first 2 years of life and neurodevelopmental scores.

RESULTS

Seven observational studies (282 participants) met the inclusion criteria. All studies compared continuation of breast feeding with low-Phe formula versus formula feeding only. While most studies concluded that there was no difference in mean serum Phe levels in their follow-up period, two reported that breastfed infants were more likely to have a normal mean Phe level. Two studies described no difference in mean weight gain after birth, while one found that breastfed infants were more likely to have higher mean weight gain. Two studies commented that breastfed infants achieved higher developmental scores in childhood as compared with formula fed infants.

CONCLUSION

Although there are no randomised trials, observational evidence suggests that continuation of breast feeding and supplementation with low-Phe formula is safe and may be beneficial for infants diagnosed with PKU.

Valorization of pistachio industrial waste: Simultaneous recovery of pectin and phenolics, and their application in low-phenylalanine cookies for phenylketonuria

This study introduces a sustainable approach to simultaneously produce pectin and phenolic compounds from pistachio industrial waste and applies them in the formulation of low-phenylalanine cookies. The co-optimization process was performed using the microwave-assisted technique and a Box-Behnken design, considering four variables and two responses: pectin yield and total phenolic content (TPC). The co-optimized condition (microwave power of 700 W, irradiation time of 210 s, pH level of 1.02, and LSR of 20 mL/g) resulted in a pectin yield of 15.85 % and a TPC of 10.12 %. The pectin obtained under co-optimized condition was evaluated for its physicochemical, structural, and thermal properties and the phenolic extract for its antiradical activity. Characterization of the pectin sample revealed a high degree of esterification (44.21 %) and a galacturonic acid-rich composition (69.55 %). The average molecular weight of the pectin was determined to be 640.236 kDa. FTIR and 1H NMR spectroscopies confirmed the structure of pectin, with an amorphous nature and high thermal stability observed through XRD and DSC analysis. Additionally, the extract exhibited significant antiradical activity comparable to butylated hydroxyanisole and ascorbic acid. The isolated ingredients were used to formulate low-protein, low-phenylalanine cookies for phenylketonuria patients. The addition of 0.5 % pectin and 1 mL/g extract led to increased moisture content (from 9.05 to 12.89 %) and specific volume (from 7.28 to 9.90 mL/g), decreased hardness (from 19.44 to 10.39 N × 102), and improved antioxidant properties (from 5.15 % to 44.60 % inhibition) of the cookies. Importantly, there was no significant increase observed in the phenylalanine content of the samples with pectin and extract addition. Furthermore, sensory evaluation scores demonstrated significantly higher scores for taste, odor, texture, and overall acceptability in cookies enriched with 0.5 % pectin and 1 mL/g extract, with scores of 4.53, 3.93, 4.40, and 4.60, respectively.

Feeding difficulties in patients with Phenylketonuria

PURPOSE

to analyze the results of an instrument that aims to assist in the identification of feeding difficulties in children with Phenylketonuria (PKU), compared to children without the disease.

METHODS

cross-sectional, controlled study with a convenience sample composed of patients with PKU and healthy individuals, matched for age and sex. The invitation to participate in the study was made through the dissemination of the research on social networks. The answers were provided by the guardians, 46 controls and 28 patients agreed to participate. In addition to these, 13 guardians of patients being followed up at an Outpatient Clinic for the Treatment of Inborn Errors of Metabolism were invited by phone call, and 12 accepted the invitation. All participants answered the Brazilian Infant Feeding Scale (in Portuguese Escala Brasileira de Alimentação Infantil (EBAI)) electronically.

RESULTS

the study included 86 participants, 40 patients (median of age = 2 years; interquartile range (IQR) = 2 - 4) and 46 controls (median of age = 3.5 years; IQR = 2 - 5.25). Ten (25%) patients and 13 (28.3%) controls had suspicion of feeding difficulties, demonstrating a similar frequency of feeding difficulties between groups. The study found that PKU patients had less feed autonomy (p = 0.005), were less breastfed (p = 0.002) and used more baby's bottle than controls (p = 0.028).

CONCLUSION

the frequency of feeding difficulties reported by caregivers was similar between the comparison groups, but children with PKU had less feed autonomy, were less breastfed and used more baby's bottles when compared to children without the disease.

Health-related quality of life in a european sample of adults with early-treated classical PKU

BACKGROUND

Phenylketonuria (PKU) is a rare inborn error of metabolism affecting the catabolism of phenylalanine (Phe). To date, findings regarding health-related quality of life (HRQoL) in adults with early-treated classical PKU are discrepant. Moreover, little is known about metabolic, demographic, and cognitive factors associated with HRQoL. Hence, we aimed to investigate HRQoL and its association with demographic, metabolic, and cognitive characteristics in a large European sample of adults with early-treated classical PKU.

RESULTS

This cross-sectional study included 124 adults with early-treated classical PKU from Hungary, Italy, Spain, Switzerland, and Turkey. All participants prospectively completed the PKU quality of life questionnaire (PKU-QoL), a questionnaire specifically designed to evaluate the impact of PKU and its treatment on HRQoL in individuals with PKU. In addition, information about Phe levels (concurrent and past year), demographic (age and sex), and cognitive variables (intelligence quotient, IQ) were collected. Most domains revealed little or no impact of PKU on HRQoL and more than three-quarters of the patients rated their health status as good, very good, or excellent. Nevertheless, some areas of concern for patients were identified. Patients were worried about the guilt that they experience if they do not adhere to the dietary protein restriction and they were most concerned about high Phe levels during pregnancy. Further, tiredness was the most affected symptom, and the supplements' taste was considered a main issue for individuals with PKU. The overall impact of PKU on HRQoL was higher in women (U = 1315.5, p = .012) and in adults with a lower IQ (rs = - 0.448, p = .005). The overall impact of dietary protein restriction was higher in adults with higher concurrent Phe levels (rs = 0.272, p = .007) and higher Phe levels during the past year (rs = 0.280, p = .009).

CONCLUSION

The impact of PKU on most domains assessed in the PKU-QoL was considered to be low. These results likely reflect the successful implementation of the newborn screening resulting in the prevention of severe adverse long-term outcomes. However, a particular clinical focus should be given to patients with lower IQ, higher Phe levels, and women, as these variables were associated with a lower HRQoL.

Mothers' Views on the Storage and Usage of Their Children's Biological Material Under the Danish Biobanking Model: A Narrative Approach Using Epistemic Injustice

OBJECTIVES

To investigate the knowledge and attitudes of mothers living in Denmark on the storage and usage of their children's biological material. The Danish Neonatal Screening Biobank contains blood from the Phenylketonuria-screening test. Legal, ethical, and moral concerns have been raised in several countries of how consent is obtained best in pediatric biobank governance. Research on knowledge and attitudes of Danish parents on the usage of their children's biological material is scarce.

METHODS

A coproduced study between a mother and 2 researchers. We analyzed 5 online focus group interviews using Ricoeur's hermeneutical narrative analysis.

RESULTS

Mothers have very little knowledge on the storage and usage of their children's biological material. They consider the Phenylketonuria-screening test to be part of a birth package, which leaves very little option of choice. They accept donating the material as a token of appreciation in an act of altruism toward the wider society but are only comfortable supporting Danish research.

CONCLUSIONS

An exploration of the communal narrative build in the interviews reveal an overall feeling of duty to help benefit society, an overwhelming trust toward the health system, and epistemic unjust storage information practices.

Association Analysis of Gene Sequencing by NeoSeq Combined with Tandem Mass Spectrum and Four Neonatal Diseases

BACKGROUND

NeoSeq is a new method of gene sequencing for newborn screening. The goal is to explore the relationship between gene sequencing by NeoSeq combined with tandem mass spectrum (TMS) and four neonatal diseases.

METHODS

A total of 1,989 newborns from August 2010 to December 2021 were enrolled. The case number of congenital hypothyroidism, phenylketonuria, adrenocortical hyperplasia, and glucose-6-phosphate dehydrogenase deficiency was counted, and the results of gene sequencing by NeoSeq and TMS were analyzed.

RESULTS

The proportion of male newborns was higher than that of female newborns (51.68% vs. 48.32%). The detection rate of glucose-6-phosphate dehydrogenase deficiency was higher than that of the other three diseases (0.60% vs. 0.05%, 0.05%, 0.15%). A total of 121 newborns were recalled from 1989 newborns by traditional screening technique, and TMS detected phenylketonuria, citrullinemia, glutaric acidemia type I, and 3-methylcro-tonyl-CoA carboxylase deficiency in 1 newborn each. Gene sequencing by NeoSeq of newborns with positive TMS results confirmed the presence of susceptibility genes, and 17 of 1,868 newborns with normal biochemical tests had pathogenic genes.

CONCLUSIONS

The incidence of glucose-6-phosphate dehydrogenase deficiency is relatively higher in four neonatal diseases, and the detection rate of gene sequencing by NeoSeq combined with TMS is high.

Phenylalanine Tolerance over Time in Phenylketonuria: A Systematic Review and Meta-Analysis

In phenylketonuria (PKU), natural protein tolerance is defined as the maximum natural protein intake maintaining a blood phenylalanine (Phe) concentration within a target therapeutic range. Tolerance is affected by several factors, and it may differ throughout a person's lifespan. Data on lifelong Phe/natural protein tolerance are limited and mostly reported in studies with low subject numbers. This systematic review aimed to investigate how Phe/natural protein tolerance changes from birth to adulthood in well-controlled patients with PKU on a Phe-restricted diet. Five electronic databases were searched for articles published until July 2020. From a total of 1334 results, 37 articles met the eligibility criteria (n = 2464 patients), and 18 were included in the meta-analysis. The mean Phe (mg/day) and natural protein (g/day) intake gradually increased from birth until 6 y (at the age of 6 months, the mean Phe intake was 267 mg/day, and natural protein intake was 5.4 g/day; at the age of 5 y, the mean Phe intake was 377 mg/day, and the natural protein intake was 8.9 g/day). However, an increase in Phe/natural protein tolerance was more apparent at the beginning of late childhood and was >1.5-fold that of the Phe tolerance in early childhood. During the pubertal growth spurt, the mean natural protein/Phe tolerance was approximately three times higher than in the first year of life, reaching a mean Phe intake of 709 mg/day and a mean natural protein intake of 18 g/day. Post adolescence, a pooled analysis could only be performed for natural protein intake. The mean natural protein tolerance reached its highest (32.4 g/day) point at the age of 17 y and remained consistent (31.6 g/day) in adulthood, but limited data were available. The results of the meta-analysis showed that Phe/natural protein tolerance (expressed as mg or g per day) increases with age, particularly at the beginning of puberty, and reaches its highest level at the end of adolescence. This needs to be interpreted with caution as limited data were available in adult patients. There was also a high degree of heterogeneity between studies due to differences in sample size, the severity of PKU, and target therapeutic levels for blood Phe control.

A Retrospective Chart Review and Infant Feeding Survey in the Irish Phenylketonuria (PKU) Population (2016-2020)

Phenylketonuria (PKU) is an inherited disorder of protein metabolism. It is generally treated using dietary management with limited intake of phenylalanine (Phe). Partial breastfeeding (BF) is encouraged among mothers of infants with PKU, together with a Phe-free mixture of synthetic amino acids. Our aim was to describe our current BF rates and complementary feeding practices, as well as examining parental experiences of infant feeding. The objective was to better understand the challenges faced by families so that improvements can be made to clinical care. A chart review was carried out on 39 PKU patients, examining the BF rate and duration, use of second stage synthetic protein (SP), and average complementary feeding age. A parental questionnaire on complementary feeding and BF experience was designed: 26% of babies were partially breastfed at three months of age; 70% of mums would like to have breastfed for longer and cited PKU as a reason for stopping; 52% of parents reported challenges during the complementary feeding process including food refusal, protein calculation, and anxiety around maintaining good Phe levels. Suggestions to improve BF continuation and duration include active promotion of the benefits and suitability, access to lactation consultant, and peer support. The delay in introducing a second stage SP may contribute to long-term bottle use for SP. Improved patient education, written resources, and support is necessary to improve food choices and long-term acceptance of SP.

Neuroimaging in early-treated phenylketonuria patients and clinical outcome: A systematic review

Lacking direct neuropathological data, neuroimaging exploration has become the most powerful tool to give insight into pathophysiological alterations of early-treated PKU (ETPKU) patients. We conducted a systematic review of neuroimaging studies in ETPKU patients to explore 1) the occurrence of consistent neuroimaging alterations; 2) the relationship between them and neurological and cognitive disorders; 3) the contribution of neuroimaging in the insight of neuropathological background of ETPKU subjects; 4) whether brain neuroimaging may provide additional information in the monitoring of the disease course. Thirty-eight studies met the inclusion criteria for the full-text review, including morphological T1/T2 sequences, diffusion brain imaging (DWI/DTI) studies, brain MRI volumetric, functional neuroimaging studies, neurotransmission and brain energetic imaging studies. Non-progressive brain white matter changes were the most frequent and precocious alterations. As confirmed in hundreds of young adults with ETPKU, they affect over 90% of ETPKU patients. Consistent correlations are emerging between microstructural alteration (as detected by DWI/DTI) and metabolic control, which have also been confirmed in a few interventional trials. Volumetric studies detected later and less consistent cortical and subcortical grey matter alterations, which seem to be influenced by the patient's age and metabolic control. The few functional neuroimaging studies so far showed preliminary but interesting data about cortical activation patterns, skill performance, and brain connectivity. Further research is mandatory in these more complex areas. Recurrent methodological limitations include restricted sample sizes concerning the clinical variability of the disease, large age-range, variable measures of metabolic control, and prevalence of cross-sectional rather than longitudinal interventional studies.

Metabolic phenotyping in phenylketonuria reveals disease clustering independently of metabolic control

Phenylketonuria (PKU, MIM #261600) is one of the most common inborn errors of metabolism (IEM) with an incidence of 1:10000 in the European population. PKU is caused by autosomal recessive mutations in phenylalanine hydroxylase (PAH) and manifests with elevation of phenylalanine (Phe) in plasma and urine. Untreated PKU manifests with intellectual disability including seizures, microcephaly and behavioral abnormalities. Early treatment and good compliance result in a normal intellectual outcome in many but not in all patients. This study examined plasma metabolites in patients with PKU (n = 27), hyperphenylalaninemia (HPA, n = 1) and healthy controls (n = 32) by LC- MS/MS. We hypothesized that PKU patients would exhibit a distinct "submetabolome" compared to that of healthy controls. We further hypothesized that the submetabolome of PKU patients with good metabolic control would resemble that of healthy controls. Results from this study show: (i) Distinct clustering of healthy controls and PKU patients based on polar metabolite profiling, (ii) Increased and decreased concentrations of metabolites within and afar from the Phe pathway in treated patients, and (iii) A specific PKU-submetabolome independently of metabolic control assessed by Phe in plasma. We examined the relationship between PKU metabolic control and extended metabolite profiles in plasma. The PKU submetabolome characterized in this study represents the combined effects of dietary adherence, adjustments in metabolic pathways to compensate for defective Phe processing, as well as metabolic derangements that could not be corrected with dietary management even in patients classified as having good metabolic control. New therapeutic targets may be uncovered to approximate the PKU submetabolome to that of healthy controls and prevent long-term organ damage.

The effects of a self-learning package on mothers' knowledge and practices towards caring for their children with phenylketonuria

The objective of this study was to evaluate the effect of a self-learning package on mothers' knowledge and practices towards caring for their children with phenylketonuria. A pre/post quasi-experimental study was conducted, including 128 mothers of children diagnosed with phenylketonuria. A specifically designed and validated questionnaire was used to evaluate mothers' knowledge and reported practices toward their children before and after participating in the educational program. There was a highly positive association between knowledge and reported practice (.674 and .398). The self-learning package had a positive impact on mothers' knowledge and practices. Consequently, educational programs should be provided to all mothers of newly diagnosed cases to improve their children's adherence to the therapeutic regimen.

Charles Scriver: Epitome of the physician scientist

Charles Scriver is a towering figure in the medical genetics community. At 92 he can look back upon a remarkable career that established the field of biochemical genetics, a subsection of medical genetics that is translating the developments in basic genetics into the diagnoses and treatments of inherited biochemical diseases. This biographical sketch summarizes the key achievements of Dr. Scriver in research and medicine, integrating the different components of medical genetics into comprehensive provincial programs, teaching a generation of physicians and researchers, and developing worldwide collaborations. Charles has been a mighty figure in so many ways. He began his career by bringing amino acid chromatography from London to North America, thereby greatly enlarging the scope of metabolic disorders. Subsequently, his editorship of the classic Metabolic and Molecular Bases of Inherited Disease brought metabolism into genetics and established the field of biochemical genetics. He discovered a number of new diseases and was the first to recognize shared mediated amino acid transporters in the kidney, a medical breakthrough that has become a basic concept of amino acid homeostasis. He led the formation of the Quebec Network of Genetic Medicine, incorporating screening, diagnosis, counseling, treatment and research of genetic diseases, which to this day serves as a model for collaborative and comprehensive medical genetic programs internationally. He initiated the development of sapropterin (Kuvan®), the first non-dietary treatment for phenylketonuria (PKU) and helped identify the mechanism of this cofactor's action on phenylalanine hydroxylase in variants of PKU. His laboratory also led the development of phenylalanine ammonia lyase (Palynziq®), an enzyme substitution therapy that now serves as an alternative to dietary treatment for PKU. The ecosystem that Charles generated at the deBelle laboratory was collegial and highly fruitful. With the input and support of his remarkable wife Zipper, he found a way to integrate the concept of family into his work environment. Bustling with an endless series of evolving activities, he generated an inclusive setting which drew on the talents of brilliant clinical and research staff, as well as the input of patients and their families. In all these efforts, Charles managed to answer his own musings summarized in the following three questions: Who do we serve? How do we serve? Why do we serve? Charles Scriver's life is one well lived. An extraordinary physician scientist whose accomplishments are cause for pause and wonder; generating volumes of contribution which will forever seem impossible for one individual to deliver.

Complications of the Low Phenylalanine Diet for Patients with Phenylketonuria and the Benefits of Increased Natural Protein

Phenylketonuria (PKU) is an inherited disorder in which phenylalanine (Phe) is not correctly metabolized leading to an abnormally high plasma Phe concentration that causes profound neurologic damage if left untreated. The mainstay of treatment for PKU has centered around limiting natural protein in the diet while supplementing with medical foods in order to prevent neurologic injury while promoting growth. This review discusses several deleterious effects of the low Phe diet along with benefits that have been reported for patients with increased natural protein intake while maintaining plasma Phe levels within treatment guidelines.

Cortical thickness and its relationship to cognitive performance and metabolic control in adults with phenylketonuria

Despite good control of phenylalanine (Phe) levels during childhood and adolescence, adults with phenylketonuria (PKU) often show abnormalities in the white matter of the brain, which have been associated with poorer cognitive performance. However, whether such a relationship exists with cortical gray matter is still unknown. Therefore, we investigated cortical thickness and surface area in adults with early-treated PKU and their relationship to cognitive functions and metabolic control. We included 30 adult patients with early-treated and metabolically well-controlled PKU (median age: 35.5 years) and 54 healthy controls (median age: 29.3 years). Surface-based morphometry was derived from T1-weighted magnetic resonance images using FreeSurfer, and general intelligence, executive functions, and attention were assessed. Concurrent plasma Phe, tyrosine, and tryptophan levels were measured in patients. In addition, Phe levels were collected retrospectively to calculate the index of dietary control. Patients showed a thinner cortex than controls in regions of the bilateral temporal, parietal, and occipital lobes (effect size r = -0.34 to -0.42, p < 0.05). No group differences in surface area were found. In patients, accuracy in the working memory task was positively correlated with thickness in the left insula (r = 0.45, p = 0.013), left fusiform gyrus (r = 0.39, p = 0.032), and right superior temporal gyrus (r = 0.41, p = 0.024), but did not survive false discovery rate correction. Neither concurrent nor historical metabolic parameters were related to cortical thickness. Taken together, adults with PKU showed widespread reductions in cortical thickness despite good metabolic control in childhood and adolescence. However, alterations in cortical thickness were unrelated to metabolic parameters and cognitive performance.

Impact of pregnancy planning and preconceptual dietary training on metabolic control and offspring's outcome in phenylketonuria

To prevent maternal phenylketonuria (PKU) syndrome low phenylalanine concentrations (target range, 120-360 μmol/L) during pregnancy are recommended for women with PKU. We evaluated the feasibility and effectiveness of current recommendations and identified factors influencing maternal metabolic control and children's outcome. Retrospective study of first successfully completed pregnancies of 85 women with PKU from 12 German centers using historical data and interviews with the women. Children's outcome was evaluated by standardized IQ tests and parental rating of child behavior. Seventy-four percent (63/85) of women started treatment before conception, 64% (54/85) reached the phenylalanine target range before conception. Pregnancy planning resulted in earlier achievement of the phenylalanine target (18 weeks before conception planned vs. 11 weeks of gestation unplanned, p < 0.001) and lower plasma phenylalanine concentrations during pregnancy, particularly in the first trimester (0-7 weeks of gestation: 247 μmol/L planned vs. 467 μmol/L unplanned, p < 0.0001; 8-12 weeks of gestation: 235 μmol/L planned vs. 414 μmol/L unplanned, p < 0.001). Preconceptual dietary training increased the success rate of achieving the phenylalanine target before conception compared to women without training (19 weeks before conception vs. 9 weeks of gestation, p < 0.001). The majority (93%) of children had normal IQ (mean 103, median age 7.3 years); however, IQ decreased with increasing phenylalanine concentration during pregnancy. Good metabolic control during pregnancy is the prerequisite to prevent maternal PKU syndrome in the offspring. This can be achieved by timely provision of detailed information, preconceptual dietary training, and careful planning of pregnancy.

The relationship between metabolic control and basal ganglia morphometry and function in individuals with early-treated phenylketonuria

Abnormalities of the cortical white matter are the most prominent and widely-reported neurological findings in individuals with early-treated phenylketonuria (ETPKU). Much less is known regarding the effects of ETPKU on gray matter structures in the brain such as the basal ganglia. Previous findings on basal ganglia in ETPKU have been mixed. The current study was designed to further elucidate the effects of ETPKU and elevated phe levels on the morphometry of basal ganglia structures (i.e., putamen, caudate nucleus, nucleus accumbens, and globus pallidus). High resolution magnetic resonance imaging (MRI) data was collected from a sample of 37 adults with ETPKU and a demographically-matched comparison group of 33 individuals without PKU. No overall group differences (ETPKU vs. non-PKU) in basal ganglia volumes were observed. However, within the ETPKU group, poorer metabolic control (as reflected by higher blood phenylalanine levels) was associated with larger putamen volume. Vertex-wise shape analysis revealed that the volume increase was accompanied by shape changes in the middle left putamen. Consistent with this area's role in motor control, a significant correlation between left putamen volume and motor performance was also observed. Additional research is needed to fully understand the cellular level processes underlying this effect as well as to better understand the clinical impact of these morphometric changes and their potential relation to treatment response.

Impact of Fruit and Vegetable Protein vs. Milk Protein on Metabolic Control of Children with Phenylketonuria: A Randomized Crossover Controlled Trial

Fruits and vegetables containing phenylalanine ≤ 75 mg/100 g (except potatoes) have little impact on blood phenylalanine in phenylketonuria (PKU). In a randomized, controlled, crossover intervention trial, we examined the effect of increasing phenylalanine intake from fruits and vegetables, containing phenylalanine 76−100 mg /100 g, compared with milk protein sources on blood phenylalanine control. This was a five-phase study (4 weeks each phase). In Phase A, patients remained on their usual diet and then were randomly allocated to start Phase B and C (an additional phenylalanine intake of 50 mg/day, then 100 mg from fruits and vegetables containing phenylalanine 76−100 mg/100 g) or Phase D and E (an additional phenylalanine intake of 50 mg/day then 100 mg/day from milk sources). There was a 7-day washout with the usual phenylalanine-restricted diet between Phase B/C and D/E. Blood phenylalanine was measured on the last 3 days of each week. If four out of six consecutive blood phenylalanine levels were >360 μmol/L in one arm, this intervention was stopped. Sixteen patients (median age 10.5 y; range 6−12 y) were recruited. At baseline, a median of 6 g/day (range: 3−25) natural protein and 60 g/day (range: 60−80) protein equivalent from protein substitute were prescribed. Median phenylalanine levels were: Phase A—240 μmol/L; Phase B—260 μmol/L; Phase C—280 μmol/L; Phase D—270 μmol/L and Phase E—280 μmol/L. All patients tolerated an extra 50 mg/day of phenylalanine from fruit and vegetables, containing phenylalanine 76−100 mg/100 g, but only 11/16 (69%) tolerated an additional 100 mg /day. With milk protein, only 8/16 (50%) tolerated an extra 50 mg/day and only 5/16 (31%) tolerated an additional 100 mg/day of phenylalanine. Tolerance was defined as maintaining consistent blood phenylalanine levels < 360 μmol/L throughout each study arm. There was a trend that vegetable protein had less impact on blood phenylalanine control than milk protein, but overall, the differences were not statistically significant (p = 0.152). This evidence supports the PKU European Guidelines cutoff that fruit and vegetables containing 76−100 mg phenylalanine/100 g should be calculated as part of the phenylalanine exchange system. Tolerance of the ‘free use’ of these fruits and vegetables depends on inter-patient variability but cannot be recommended for all patients with PKU.

Neurocognitive outcome and mental health in children with tyrosinemia type 1 and phenylketonuria: A comparison between two genetic disorders affecting the same metabolic pathway

Tyrosinemia type 1 (TT1) and phenylketonuria (PKU) are both inborn errors of phenylalanine-tyrosine metabolism. Neurocognitive and behavioral outcomes have always featured in PKU research but received less attention in TT1 research. This study aimed to investigate and compare neurocognitive, behavioral, and social outcomes of treated TT1 and PKU patients. We included 33 TT1 patients (mean age 11.24 years; 16 male), 31 PKU patients (mean age 10.84; 14 male), and 58 age- and gender-matched healthy controls (mean age 10.82 years; 29 male). IQ (Wechsler-subtests), executive functioning (the Behavioral Rating Inventory of Executive Functioning), mental health (the Achenbach-scales), and social functioning (the Social Skills Rating System) were assessed. Results of TT1 patients, PKU patients, and healthy controls were compared using Kruskal-Wallis tests with post-hoc Mann-Whitney U tests. TT1 patients showed a lower IQ and poorer executive functioning, mental health, and social functioning compared to healthy controls and PKU patients. PKU patients did not differ from healthy controls regarding these outcome measures. Relatively poor outcomes for TT1 patients were particularly evident for verbal IQ, BRIEF dimensions "working memory", "plan and organize" and "monitor", ASEBA dimensions "social problems" and "attention problems", and for the SSRS "assertiveness" scale (all p values <0.001). To conclude, TT1 patients showed cognitive impairments on all domains studied, and appeared to be significantly more affected than PKU patients. More attention should be paid to investigating and monitoring neurocognitive outcome in TT1 and research should focus on explaining the underlying pathophysiological mechanism.

Spatio-temporal dynamics of pathogenic variants associated with monogenic disorders reconstructed with ancient DNA

Genetic disease burden in ancient communities has barely been evaluated despite an ever expanding body of ancient genomes becoming available. In this study, we inspect 2729 publicly available ancient genomes (100 BP—52000 BP) for the presence of pathogenic variants in 32643 disease-associated loci. We base our subsequent analyses on 19 variants in seven genes—PAH, EDAR, F11, HBB, LRRK2, SLC12A6 and MAOA, associated with monogenic diseases and with well-established pathogenic impact in contemporary populations. We determine 230 homozygote genotypes of these variants in the screened 2729 ancient DNA samples. Eleven of these are in the PAH gene (126 ancient samples in total), a gene associated with the condition phenylketonuria in modern populations. The variants examined seem to show varying dynamics over the last 10000 years, some exhibiting a single upsurge in frequency and subsequently disappearing, while others maintain high frequency levels (compared to contemporary population frequencies) over long time periods. The geographic distribution and age of the ancient DNA samples with established pathogenic variants suggests multiple independent origin of these variants. Comparison of estimates of the geographic prevalence of these variants from ancient and contemporary data show discontinuity in their prevalence and supports their recurrent emergence. The oldest samples in which a variant is established might give an indication of their age and place origin, and an EDAR gene pathogenic variant was established in a sample estimated to be 33210–32480 calBCE. Knowledge about the historical prevalence of variants causing monogenic disorders provides insight on their emergence, dynamics and spread.

Psychiatric Manifestations in Patients with Biopterin Defects

Psychiatric manifestations in patients with tetrahydrobiopterin (BH4) defects are common, and may occur even with treatment of the underlying disorder. The neurobiological background of these conditions has been linked to abnormalities of neurotransmitters, such as dopamine, serotonin, norepinephrine, and gamma-aminobutyric acid. Here, we review the psychiatric profile of all patients with BH4 defects followed in the pediatric and adult metabolic clinics at our center. Three patients with autosomal recessive (AR) guanosine triphosphate cyclohydrolase (GTPCH) deficiency and three patients with 6-pyruvoyl tetrahydropterin synthase (PTPS) deficiency were reviewed.All patients had behavioral disturbances and two had significant psychiatric comorbidities. These included attention deficit/hyperactivity disorder, anxiety, depression, aggression, or oppositional defiant disorder. One patient with PTPS deficiency had a severe psychiatric presentation, requiring inpatient admission and temporary placement into foster care for intensive behavioral therapy. Another with AR GTPCH deficiency was diagnosed with aggressive behavioral dysregulation requiring intensive psychiatric treatment. Management of the psychiatric manifestations of BH4 defects can be challenging, due to lack of information and studies of interactions between psychiatric medications on the deficient neurotransmitters and their receptors in these conditions. Further studies are needed to establish safety and efficacy of these treatments.

Evaluation of patients with phenylalanine metabolism disorder: a single center experience

AIM

The aim is to evaluate the clinical, demographic and laboratory data of the patients we followed up with phenylalanine metabolism disorder.

MATERIALS AND METHODS

In this study, patients with phenylalanine metabolism disorder who applied to Bursa Uludag University Faculty of Medicine, Department of Pediatrics, Pediatric Metabolism Department between 2011 and 2021 were retrospectively examined. The files of 397 patients who were followed up in our pediatric metabolism outpatient clinic and were found to have phenylalanine metabolism disorder by plasma phenylalanine level and molecular genetic analysis were evaluated.

RESULTS

According to the highest plasma phenylalanine levels at admission, mild hyperphenylalaninemia phenotype constituted the largest group of 397 patients with 282 cases (71.1%), while the least common phenotype was malignant phenylketonuria (BH4 metabolism disorder) with four patients (1.0%). The number of patients with classical phenylketonuria was 90 (22.6%). 61 (62.8%) of 97 phenylalanine metabolism disorder cases who underwent BH4 loading test had a response. The mean phenylalanine level of the patients was 3.62 ± 1.31 mg/dL in mild hyperphenylalaninemia, 7.98 ± 3.99 mg/dL in mild phenylketonuria and 11.71 ± 4.39 mg/dL in classical phenylketonuria. While 241 (76%) of 317 patients younger than 8 years old were in the well-controlled group, 76 (24%) were in the poorly-controlled group. While 41 (53.9%) of 76 patients older than 8 years of age were in the well-controlled group, 35 (46.1%) were in the poorly-controlled group.

CONCLUSIONS

In our study, the largest patient group consisted of patients with mild hyperphenylalaninemia, and the least common phenotype was mild phenylketonuria.

Dietetic Management of Adults with Phenylketonuria (PKU) in the UK: A Care Consensus Document

There is an increasing number of adults and elderly patients with phenylketonuria (PKU) who are either early, late treated, or untreated. The principal treatment is a phenylalanine-restricted diet. There is no established UK training for dietitians who work with adults within the specialty of Inherited Metabolic Disorders (IMDs), including PKU. To address this, a group of experienced dietitians specializing in IMDs created a standard operating procedure (SOP) on the dietetic management of adults with PKU to promote equity of care in IMD dietetic services and to support service provision across the UK. The group met virtually over a period of 12 months until they reached 100% consensus on the SOP content. Areas of limited evidence included optimal blood phenylalanine reporting times to patients, protein requirements in older adults, management of weight and obesity, and management of disordered eating and eating disorders. The SOP does not include guidance on maternal PKU management. The SOP can be used as a tool for training dietitians new to the specialty and to raise the standard of education and care for patients with PKU in the UK.

Italian national consensus statement on management and pharmacological treatment of phenylketonuria

BACKGROUND

Phenylketonuria (PKU) is a rare inherited metabolic disorder caused by defects in the phenylalanine-hydroxylase gene (PAH), the enzyme catalyzing the conversion of phenylalanine to tyrosine. PAH impairment causes phenylalanine accumulation in the blood and brain, with a broad spectrum of pathophysiological and neurological consequences for patients. Prevalence of disease varies, with peaks in some regions and countries, including Italy. A recent expert survey described the real-life of clinical practice for PKU in Italy, revealing inhomogeneities in disease management, particularly concerning approach to pharmacotherapy with sapropterin hydrochloride, analogous of the natural PAH co-factor, allowing disease control in a subset of patients. Therefore, the purpose of this paper is to continue the work initiated with the expert survey paper, to provide national guidances aiming to harmonize and optimize patient care at a national level.

PARTICIPANTS

The Consensus Group, convened by 10 Steering Committee members, consisted of a multidisciplinary crowd of 46 experts in the management of PKU in Italy.

CONSENSUS PROCESS

The Steering Committee met in a series of virtual meeting in order to discuss on clinical focuses to be developed and analyzed in guidance statements, on the basis of expert practice based evidence, large systematic literature review previously performed in the expert survey paper, and evidence based consensus published. Statements were re-discussed and refined during consensus conferences in the widest audience of experts, and finally submitted to the whole consensus group for a modified-Delphi voting.

RESULTS

Seventy three statements, divided in two main clinical areas, PKU management and Pharmacotherapy, achieved large consensus in a multidisciplinary group of expert in different aspects of disease. Importantly, these statements involve guidances for the use of sapropterin dihydrochloride, still not sufficiently implemented in Italy, and a set of good practice to approach the use of novel enzyme replacement treatment pegvaliase.

CONCLUSIONS

This evidence-based consensus provides a minimum set of guidances for disease management to be implemented in all PKU centers. Moreover, these guidances represent the first statement for sapropterin dihydrochloride use, implementation and standardization in Italy, and a guide for approaching pegvaliase treatment at a national level on a consistent basis.

L-carnitine protects DNA oxidative damage induced by phenylalanine and its keto acid derivatives in neural cells: a possible pathomechanism and adjuvant therapy for brain injury in phenylketonuria

Although phenylalanine (Phe) is known to be neurotoxic in phenylketonuria (PKU), its exact pathogenetic mechanisms of brain damage are still poorly known. Furthermore, much less is known about the role of the Phe derivatives phenylacetic (PAA), phenyllactic (PLA) and phenylpyruvic (PPA) acids that also accumulate in this this disorder on PKU neuropathology. Previous in vitro and in vivo studies have shown that Phe elicits oxidative stress in brain of rodents and that this deleterious process also occurs in peripheral tissues of phenylketonuric patients. In the present study, we investigated whether Phe and its derivatives PAA, PLA and PPA separately or in combination could induce reactive oxygen species (ROS) formation and provoke DNA damage in C6 glial cells. We also tested the role of L-carnitine (L-car), which has been recently considered an antioxidant agent and easily cross the blood brain barrier on the alterations of C6 redox status provoked by Phe and its metabolites. We first observed that cell viability was not changed by Phe and its metabolites. Furthermore, Phe, PAA, PLA and PPA, at concentrations found in plasma of PKU patients, provoked marked DNA damage in the glial cells separately and when combined. Of note, these effects were totally prevented (Phe, PAA and PPA) or attenuated (PLA) by L-car pre-treatment. In addition, a potent ROS formation also induced by Phe and PAA, whereas only moderate increases of ROS were caused by PPA and PLA. Pre-treatment with L-car also prevented Phe- and PAA-induced ROS generation, but not that provoked by PLA and PPA. Thus, our data show that Phe and its major metabolites accumulated in PKU provoke extensive DNA damage in glial cells probably by ROS formation and that L-car may potentially represent an adjuvant therapeutic agent in PKU treatment.