Pegvaliase therapy for phenylketonuria: Real-world case series and clinical insights.

OBJECTIVE: The aim of this study is to present a series of case studies on the real-life use of pegvaliase in Italy in managing patients affected by phenylketonuria (PKU) and provide practical insight and support to healthcare professionals currently approaching and facing this novel enzyme substitution therapy. METHODS: A panel of 11 PKU experts from seven leading Italian treatment centers attended online virtual meetings with the aim of reviewing their clinical and practical experiences with pegvaliase based on occurred cases. In selecting the cases, specific consideration was given to the nationwide representation of the centers involved and to the number of patients with PKU managed. Cases were thoroughly reviewed, with comprehensive discussions enabling the identification of key take-home messages regarding pegvaliase therapy. RESULTS: The panel discussed 18 cases, 11 males and 7 females (age range 17-43 years). At the last follow-up (up to 111 weeks after pegvaliase initiation), 11 out of 18 patients (61%) reached Phe levels below 600 µmol/l. Outcomes varied significantly across cases. All cases underscore the potential of pegvaliase in reducing Phe levels, enhancing the quality of life, and promoting social skills and independence. Additionally, the cases highlight the challenges associated with pegvaliase therapy, including managing adverse events and ensuring patient motivation and adherence. CONCLUSION: This is the first report about the Italian experience of managing patients affected by PKU with pegvaliase. Given the limited real-world data on the use of pegvaliase in PKU management, this case series offers valuable insights into the practical implementation and management of pegvaliase therapy in this Country. Continued research and data collection will be crucial to confirm and progress with this treatment. Despite potential challenges, pegvaliase therapy represents a substantial promise in managing PKU in Italy. Patient education, personalized treatment approaches, and careful monitoring are important to ensure optimal patient outcomes.

Effect of enzyme substitution therapy on brain magnetic resonance imaging and cognition in adults with phenylketonuria: A case series of three patients.

Phenylketonuria, the most common inherited metabolic disease, results from a deficiency of phenylalanine hydroxylase enzyme activity that causes high blood phenylalanine levels. Most adults do not adhere to the gold standard therapy: lifelong treatment with a low-phenylalanine diet. Elevated and fluctuating phenylalanine levels in untreated adults can cause white matter abnormalities, neurological symptoms, and cognitive dysfunction (executive function). Pegvaliase, a derivative of the phenylalanine ammonia-lyase enzyme, metabolizes phenylalanine to trans-cinnamic acid and ammonia, and is approved by the US Food and Drug Administration and European Medicines Agency for subcutaneous administration in adults with phenylketonuria and blood phenylalanine concentrations > 600 µmol/L. In clinical trials, it reduced blood phenylalanine, even in patients consuming an unrestricted diet. We report longitudinal results on the first three such adults, in whom phenylalanine levels were quantified monthly, starting 1 year before pegvaliase administration and continuing through achievement of a pegvaliase response (defined as six consecutive monthly blood phenylalanine concentrations < 360 µmol/L while consuming an unrestricted diet). Brain magnetic resonance imaging (MRI) and neuropsychological assessments were performed before starting therapy and after response was achieved. Our results show that all three patients had significantly reduced white matter hyperintensities on brain MRI and improved executive function on neuropsychological assessment, especially on the Paced Auditory Serial Addition Test, which is known to be very sensitive to white matter functioning. To the best of our knowledge, this is the first report of concomitant improvements in cognitive performance and white matter damage after a pharmacological intervention to normalize phenylalanine levels in adults with phenylketonuria consuming an unrestricted diet.

Availability of psychological resources for parents receiving communication of positivity at newborn screening for metabolic diseases in Italy.

Receiving information in the case of a positive or false-positive expanded newborn screening (ENBS) result for metabolic diseases is a stressful event. The availability of psychological support to families is crucial across the different communication steps and is recommended by different guidelines and position papers. However, more information is needed about the availability of psychological resources in the ENBS process. This national survey aimed to provide an overview of the availability of psychological resources for parents who received communication of positivity at the ENBS in the 23 Italian centers and how the support is provided to parents. An online survey was sent to the Heads of the ENBS centers asking about the availability of a clinical psychologist, their involvement in the ENBS process, and an estimation of parents receiving psychological support. More than 60% of the centers report having a clinical psychologist in the ENBS team; however, in more than 50% of cases, the psychologist does not participate in the consultation with parents (nor for the first consultation post-positivity or at confirmation of diagnosis). Furthermore, nearly 60% of the centers reported the experience of parental rejection of psychological sessions.  Conclusion: There is a need for harmonization among the Italian ENBS centers concerning the availability of psychological resources and how these resources are provided to families. Parents' needs remained only partially fulfilled. What is Known: • Receiving communication of positivity at the ENBS can be highly stressful for parents and requires adequate psychological support. • The guidelines recommend psychological support for parents during the ENBS process. What is New: • Only 14/23 (60.9%) of Italian ENBS centers have a clinical psychologist within the team. • In half of the consultations with parents receiving communication of positivity, the clinical psychologist is never involved.

Long-term follow-up of a patient with neonatal form of Gaucher disease.

Gaucher disease is the most common of the lysosomal storage diseases. It presents a wide phenotypic continuum, in which one may identify the classically described phenotypes, including type 1 form with visceral involvement, type 2 acute neuropathic early-infantile form, and type 3 subacute neuronopathic form. At the most severe end there is the perinatal form with onset in utero or during the neonatal period. The very few reported cases of neonatal onset Gaucher disease presented high and early mortality, due to neurological or visceral involvement, including liver failure. We report our experience treating a patient with the neonatal form of Gaucher disease who presented at birth with thrombocytopenia, hepatosplenomegaly and cholestasis. Despite early enzyme replacement therapy, liver disease was progressive. Liver biopsy showed hepatocellular giant-cell transformation, a nonspecific finding consistent with inflammation. The lack of response to enzyme replacement therapy and the microscopic findings suggested that mechanisms apart from substrate accumulation and Gaucher cells may play a role in the hepatic pathogenesis in Gaucher disease. An attempt to use corticosteroids at the age of 3 months resulted in a dramatic improvement in liver function and resulted in long-term survival. The patient is alive and 2 years old at this writing. Our case suggests that inflammatory processes may be important in the early pathogenesis of Gaucher disease and that early use of corticosteroids may open the way to a new therapeutic approach.

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.

Detection of 3-O-methyldopa in dried blood spots for neonatal diagnosis of aromatic L-amino-acid decarboxylase deficiency: The northeastern Italian experience.

OBJECTIVE: Aromatic L-amino acid decarboxylase (AADC) deficiency is a rare inherited autosomal recessive disorder of biogenic amine metabolism. Diagnosis requires analysis of neurotransmitter metabolites in cerebrospinal fluid, AADC enzyme activity analysis, or molecular analysis of the DDC gene. 3-O-methyldopa (3-OMD) is a key screening biomarker for AADC deficiency. METHODS: We describe a rapid method for 3-OMD determination in dried blood spots (DBS) using flow-injection analysis tandem mass spectrometry with NeoBase™ 2 reagents and 13C6-tyrosine as an internal standard, which are routinely used in high-throughput newborn screening. We assessed variability using quality control samples over a range of 3-OMD concentrations. RESULTS: Within-day and between-day precision determined with quality control samples demonstrated coefficients of variation <15%. 3-OMD concentrations in 1000 healthy newborns revealed a mean of 1.33 µmol/L (SD ± 0.56, range 0.61-3.05 µmol/L), 100 non-AADC control subjects (age 7 days - 1 year) showed a mean of 1.19 µmol/L (SD ± 0.35-2.00 µmol/L), and 81 patients receiving oral L-Dopa had a mean 3-OMD concentration of 14.90 µmol/L (SD ± 14.18, range 0.4-80.3 µmol/L). A patient with confirmed AADC was retrospectively analyzed and correctly identified (3-OMD 10.51 µmol/L). In April 2020, we started a pilot project for identifying AADC deficiency in DBSs routinely submitted to the expanded newborn screening program. 3-OMD concentrations were measured in 21,867 samples; no patients with AADC deficiency were identified. One newborn had a high 3-OMD concentration due to maternal L-Dopa treatment. DISCUSSION: We demonstrated a rapid new method to identify AADC deficiency using reagents and equipment already widely used in newborn screening programs. Although our study is limited, introduction of our method in expanded neonatal screening is feasible and could facilitate deployment of screening, allowing for early diagnosis that is important for effective treatment.

Health-related quality of life in paediatric patients with intoxication-type inborn errors of metabolism: Analysis of an international data set.

Acute intoxication-type inborn errors of metabolism (IT-IEM) such as urea cycle disorders and non-acute IT-IEM such as phenylketonuria have a major impact on paediatric patients' life. Patients have to adhere to a strict diet but may face neurocognitive impairment and - in acute diseases - metabolic decompensations nevertheless. Research on the subjective burden of IT-IEM remains sparse. Studies with appropriate sample sizes are needed to make valid statements about health-related quality of life (HrQoL) in children and adolescents with IT-IEM. Six international metabolic centres contributed self-reports and proxy reports of HrQoL (assessed with the Paediatric Quality of Life Inventory) to the final data set (n = 251 patients; age range 2.3-18.8 years). To compare HrQoL of the patient sample with norm data and between acute and non-acute IT-IEM, t tests were conducted. To examine the influence of child age, sex, diagnosis and current dietary treatment on HrQoL, multiple linear regression analyses were conducted. Self-reports and proxy reporst showed significantly lower HrQoL total scores for children with IT-IEM compared to healthy children. Current dietary treatment significantly predicted lower proxy reported total HrQoL. Children with non-acute IT-IEM reported significantly lower psychosocial health and emotional functioning than children with acute IT-IEM. The patient sample showed significantly impaired HrQoL and a diet regimen remains a risk factor for lower HrQoL. Differences in HrQoL between acute and non-acute IT-IEM subgroups indicate that factors beyond symptom severity determine the perception of disease burden. Identifying these factors is of crucial importance to develop and implement appropriate interventions for those in need.

The combined use of enzyme activity and metabolite assays as a strategy for newborn screening of mucopolysaccharidosis type I.

Objectives Mucopolysaccharidosis type I (MPS I) was added to our expanded screening panel in 2015. Since then, 127,869 newborns were screened by measuring α-L-iduronidase (IDUA) enzyme activity with liquid chromatography tandem mass spectrometry (LC-MS/MS). High false positives due to frequent pseudodeficiency alleles prompted us to develop a second-tier test to quantify glycosaminoglycan (GAG) levels in dried blood spot (DBS). Methods Heparan-sulfate (HS) and dermatan-sulfate (DS) were measured with LC-MS/MS after methanolysis. DBSs were incubated with methanolic-HCl 3 N at 65 °C for 45 min. Chromatographic separation used an amide column with a gradient of acetonitrile and water with 10 mM ammonium acetate in a 9-min run. The method was validated for specificity, linearity, lower limit of quantification (LOQ), accuracy and precision. Results Intra- and inter-day coefficients of variation were <15% for both metabolites. Reference values in 40 healthy newborns were: HS mean 1.0 mg/L, 0-3.2; DS mean 1.5 mg/L, 0.5-2.7). The two confirmed newborn MPS I patients had elevated HS (4.9-10.4 mg/L, n.v. <3.2) and DS (7.4-8.8 mg/L, n.v. <2.7). Since its introduction in February 2019, the second-tier test reduced the recall rate from 0.046% to 0.006%. Among 127,869 specimens screened, the incidence was 1:63,935 live births. Both patients started enzyme replacement therapy (ERT) within 15 days of birth and one of them received allogenic hematopoietic stem cell transplantation (HSCT) at ht age of 6 months. Conclusions GAGs in DBS increased the specificity of newborn screening for MPS I by reducing false-positives due to heterozygosity or pseudodeficiency. Early diagnosis and therapeutical approach has improved the outcome of our patients with MPS I.

The neurological and psychological phenotype of adult patients with early-treated phenylketonuria: A systematic review.

Newborn screening for phenylketonuria (PKU) and early introduction of dietary therapy has been remarkably successful in preventing the severe neurological features of PKU, including mental retardation and epilepsy. However, concerns remain that long-term outcome is still suboptimal, particularly in adult patients who are no longer on strict phenylalanine-restricted diets. With our systematic literature review we aimed to describe the neurological phenotype of adults with early-treated phenylketonuria (ETPKU). The literature search covered the period from 1 January 1990 up to 16 April 2018, using the NLM MEDLINE controlled vocabulary. Of the 643 records initially identified, 83 were included in the analysis. The most commonly reported neurological signs were tremor and hyperreflexia. The overall quality of life (QoL) of ETPKU adults was good or comparable to control populations, and there was no evidence for a significant incidence of psychiatric disease or social difficulties. Neuroimaging revealed that brain abnormalities are present in ETPKU adults, but their clinical significance remains unclear. Generally, intelligence quotient (IQ) appears normal but specific deficits in neuropsychological and social functioning were reported in early-treated adults compared with healthy individuals. However, accurately defining the prevalence of these deficits is complicated by the lack of standardized neuropsychological tests. Future research should employ standardized neurological, neuropsychological, and neuroimaging protocols, and consider other techniques such as advanced imaging analyses and the recently validated PKU-specific QoL questionnaire, to precisely define the nature of the impairments within the adult ETPKU population and how these relate to metabolic control throughout life.

Newborn screening for lysosomal storage disorders by tandem mass spectrometry in North East Italy.

BACKGROUND: Lysosomal storage diseases (LSDs) are inborn errors of metabolism resulting from 50 different inherited disorders. The increasing availability of treatments and the importance of early intervention have stimulated newborn screening (NBS) to diagnose LSDs and permit early intervention to prevent irreversible impairment or severe disability. We present our experience screening newborns in North East Italy to identify neonates with Mucopolysaccharidosis type I (MPS I) and Pompe, Fabry, and Gaucher diseases. METHODS: Activities of acid ß-glucocerebrosidase (ABG; Gaucher), acid α-glucosidase (GAA; Pompe), acid α-galactosidase (GLA; Fabry), and acid α-L-iduronidase (IDUA; MPS-I) in dried blood spots (DBS) from all newborns during a 17-month period were determined by multiplexed tandem mass spectrometry (MS/MS) using the NeoLSD® assay system. Enzymatic activity cutoff values were determined from 3500 anonymous newborn DBS. In the screening study, samples were retested if the value was below cutoff and a second spot was requested, with referral for confirmatory testing and medical evaluation if a low value was obtained. RESULTS: From September 2015 to January 2017, 44,411 newborns were screened for the four LSDs. We recalled 40 neonates (0.09%) for collection of a second DBS. Low activity was confirmed in 20, who had confirmatory testing. Ten of 20 had pathogenic mutations: two Pompe, two Gaucher, five Fabry, and one MPS-I. The incidences of Pompe and Gaucher diseases were similar (1/22,205), with Fabry disease the most frequent (1/8882) and MPS-I the rarest (1/44411). The combined incidence of the four disorders was 1/4411 births. CONCLUSIONS: Simultaneously determining multiple enzyme activities by MS/MS, with a focus on specific biochemical markers, successfully detected newborns with LSDs. The high incidence of these disorders supports this screening program.

The long-term treatment of a patient with type 1 diabetes mellitus and glutaric aciduria type 1: the effect of insulin.

UNLABELLED: The coexistence of two diseases associated with different metabolic disorders is a very rare event. Some associations, although sporadic, can be particularly challenging both in terms of diagnostic and therapeutic management and in terms of theoretical perspective. Here, we report a child affected by type 1 diabetes mellitus (T1DM) and glutaric aciduria type 1 (GA1). The child was diagnosed with classical T1DM at 15 months of age, with a tendency toward hypoglycemia. A few months later, during an acute intercurrent infective episode, the child displayed acute hypotonia of the lower limbs and limbs dystonia. A brain MRI showed bilateral striatal necrosis, suggesting GA1 diagnosis. Treatment with a low-lysine dietary regimen and carnitine supplementation was started and resulted in an improvement in metabolic control and a reduction of hypoglycemic episodes along with an increasing in insulin daily dose. After 2 years, the neurological outcome consisted of a reduction in dystonic movements and a metabolic stability of both diseases. CONCLUSION: This case provides some insight into the reciprocal interconnections between the two metabolic disorders. Similar pathogenic mechanisms responsible for the neuronal injury might have impacted each other, and a strict relationship between a specific aspect of GA1-impaired metabolism and glucose homeostasis might explain how the tailored management of GA1 was not only effective in controlling the disease, but it also resulted in an improvement in the control of the glycemic profile. What in known: • Glutaric aciduria type 1 (GA1) usually presents in childhood with severe and possibly irreversible neuronal damage, triggered by a catabolic stress • The association of GA1 with other diseases, including type 1 diabetes mellitus (T1DM), is a rare event, complicating the treatment management What is new: • Insulin treatment has a role in preventing GA1 metabolic decompensation, even in the catabolic condition of hypoglycemia • Promoting GA1 metabolic equilibrium by tailoring drug and dietary treatment in our patient affect by T1DM has a positive impact also in improving glycemic balance.

Quality of Life (QoL) assessment in a cohort of patients with phenylketonuria.

BACKGROUND: Phenylketonuria (PKU) is a chronic inborn error of amino acid metabolism that requires lifelong follow-up and intervention, which may represent strains on Quality of Life (QoL). This observational study evaluated QoL in a cohort of PKU patients, using updated and detailed instruments. METHODS: 22 patients with mild PKU respondent to BH4 and 21 patients with classical PKU treated with diet were recruited in this study. Adult patients completed WHOQOL questionnaire-100 (WHOQOL-100) and pediatric patients the Pediatric QoL inventory (PedsQL(TM)). Psychiatric and mood disorders were also evaluated using TAD or BDI and STAI-Y inventories. A multivariable linear regression model was fitted to investigate the predictors of QoL, including age, sex, treatment type, length of current treatment, educational level and employment status (only for adults) as covariates. Results were presented as regression coefficients with 95% confidence interval. RESULTS: Global QoL scores were within normal range both in patients with mild and classical disease but global QoL scores were significantly higher in patients with mild PKU under BH4 treatment as compared to those affected by classical disease who were under diet regimen. Furthermore, QoL significantly increased in long treated PKU patients. Among adult patients, QoL scores were significantly lower in males, in patients with lower education and in those employed or unemployed as compared to students (baseline). CONCLUSIONS: Both diet and medical treatment based upon BH4 seem to be associated with higher QoL in the long run. However, patients with mild PKU can rely on BH4 to achieve a higher Phe tolerance and a better compliance to therapy due to diet relaxation/avoidance. Some specific categories of patients with a lower QoL should be investigated more in depth, engaging with those at risk of lower treatment compliance. The questionnaires employed in the present study seemed to be able to effectively detect criticalities in QoL assessment and represent an advance from previous inventories employed in the past.

Unmet needs in phenylketonuria: an exploratory Italian survey among patients and caregivers.

OBJECTIVE: Patients with phenylketonuria (PKU) require a strict diet to maintain phenylalanine (Phe) levels within the desired range. However, the diet can be onerous, resulting in poor adherence. We carried out the first online national survey in Italy to better understand the perceptions, knowledge, and experiences of both patients with PKU and caregivers with the goal of improving patient outcomes. METHODS: An online survey of 35 questions to patients and 36 questions to caregivers was distributed in September 2022 through physicians and relevant Italian associations. The information collected included knowledge and impact of PKU, unmet needs, knowledge of available drugs, and satisfaction with therapy. RESULTS: Overall, 241 questionnaires were completed by 85 patients and 156 caregivers (96.0% were parents). Knowledge of the pathogenic basis of PKU was generally high. The most common patient-reported symptoms were agitation/anxiety (48.8%), fatigue (41.1%), mood disorders (39.8%), and difficulty concentrating (33.4%). Different perspectives on adherence to a low-Phe diet were observed (22.9% of patients reported strict adherence vs. 47.0% of caregivers). Drugs that allow more freedom were needed by 49.4% of patients and 61.7% of caregivers, along with a wider range of choices of non-dietary treatments (48.2% and 60.0%, respectively). Unmet informational needs of patients included PKU and pregnancy, complications, travel, sports, and transition into adult care. CONCLUSIONS: Our data showed that patients with PKU and their caregivers reported difficulties in adherence to diet therapy and indicated interest in new therapeutic approaches. Apparent differences between patient and caregiver perspectives were identified. More informational resources on PKU are needed.

Some people are born with an abnormality in a gene called phenylalanine (Phe) hydroxylase, which controls the production of an enzyme that helps convert Phe (an important amino acid that forms proteins) to tyrosine. When Phe cannot be converted to tyrosine, it builds up in the body and becomes toxic. Phenylketone bodies then form and accumulate in the blood, resulting in a disease called phenylketonuria (PKU), which can lead to intellectual disability and epilepsy. People with PKU should follow a strict low-Phe diet so that Phe levels can remain low. However, following this diet is often difficult, resulting in poor control of PKU. We carried out the first online survey in Italy to better understand the perceptions, knowledge, and experiences of patients with PKU and their caregivers. The questionnaire was distributed in Italy in September 2022. The information collected included knowledge and impact of PKU, unmet needs of patients, knowledge of available drugs, and satisfaction with therapy. Overall, 241 questionnaires were completed by 85 patients and 156 caregivers (most were parents). Knowledge of the serious consequences of PKU was generally high. The most common symptoms were agitation/anxiety (48.8%), fatigue (41.1%), mood disorders (39.8%), and difficulty concentrating (33.4%). Our data showed that patients and caregivers reported difficulties in following the strict low-Phe diet and showed interest in treatments that allowed more freedom. There were notable differences between some patient and caregiver perspectives. More informational resources on PKU and pregnancy, complications, travel, sports, and transition from child to adult care are needed.

Non-Hodgkin lymphoma in a kidney transplanted patient with methylmalonic acidemia: Metabolic susceptibility and the role of immunosuppression.

Methylmalonic acidemia cblB type (MMA cblB) is an autosomal recessive inborn error of amino acid metabolism that results in impaired synthesis of adenosylcobalamin, a cofactor of methylmalonyl-CoA mutase. It presents with episodes of coma, vomiting, hypotonia, metabolic acidosis, and hyperammonemia. End-stage kidney disease is a long-term complication. Treatments include vitamin B12 supplementation, L-carnitine, and a low-protein diet. Liver, kidney, or combined liver-kidney transplantations are promising options, but they are not without complications. We report a patient suffering from MMA cblB who developed end-stage kidney disease at 18 years of age. Kidney transplantation allowed him to recover normal kidney function and good metabolic control. Unfortunately, after two decades, he developed non-Hodgkin lymphoma and severe chemotherapy toxicity which led to his death. The risk of lymphoproliferative diseases is known to increase after solid organ transplantation. However, in MMA, factors including mitochondrial dysfunction and oncometabolites, may further increase the risk of malignancy and drug toxicity. Our report highlights the importance of considering the increased risk of cancer in long-term follow-up of MMA cblB patients, especially after solid organ transplantation. Moreover, when chemotherapy is needed, the increased risk of toxicity and metabolic decompensation should be considered and monitored.

Metabolic stroke in a late-onset form of isolated sulfite oxidase deficiency.

We report the first case of late-onset isolated sulfite oxidase deficiency (ISOD) presenting with a stroke-like episode. Clinical, biochemical and neuroradiological features at diagnosis and during follow-up after dietary treatment intervention are described. Furthermore, pathogenic mechanisms possibly leading to stroke in ISOD are discussed.

Variant in the allosteric domain of CPS1 protein associated with effectiveness of N-carbamoyl glutamate therapy in neonatal onset CPS1 deficiency.

OBJECTIVES: Carbamoyl phosphate synthetase 1 (CPS1) deficiency is a severe urea cycle disorder. Patients can present with hyperammonemic coma in the first days of life. Treatment includes nitrogen scavengers, reduced protein intake and supplementation with L-arginine and/or L-citrulline. N-carbamoyl glutamate (NCG) has been hypothesized to stimulate the residual CPS1 function, although only few patients are reported. CASE PRESENTATION: We report a patient with neonatal-onset CPS1 deficiency who received NCG in association with nitrogen scavenger and L-citrulline. The patient carried the novel variants CPS1-c.2447A>G p.(Gln816Arg) and CPS1-c.4489T>C p.(Tyr1497His). The latter is localized in the C-terminal allosteric domain of the protein, and is implicated in the binding of the natural activator N-acetyl-L-glutamate. NCG therapy was effective in controlling ammonia levels, allowing to increase the protein intake. CONCLUSIONS: Our data show that the response to NCG can be indicated based on the protein structure. We hypothesize that variants in the C-terminal domain may be responsive to NCG therapy.

Newborn Screening for Fabry Disease: Current Status of Knowledge.

Fabry disease is an X-linked progressive lysosomal disorder, due to α-galactosidase A deficiency. Patients with a classic phenotype usually present in childhood as a multisystemic disease. Patients presenting with the later onset subtypes have cardiac, renal and neurological involvements in adulthood. Unfortunately, the diagnosis is often delayed until the organ damage is already irreversibly severe, making specific treatments less efficacious. For this reason, in the last two decades, newborn screening has been implemented to allow early diagnosis and treatment. This became possible with the application of the standard enzymology fluorometric method to dried blood spots. Then, high-throughput multiplexable assays, such as digital microfluidics and tandem mass spectrometry, were developed. Recently DNA-based methods have been applied to newborn screening in some countries. Using these methods, several newborn screening pilot studies and programs have been implemented worldwide. However, several concerns persist, and newborn screening for Fabry disease is still not universally accepted. In particular, enzyme-based methods miss a relevant number of affected females. Moreover, ethical issues are due to the large number of infants with later onset forms or variants of uncertain significance. Long term follow-up of individuals detected by newborn screening will improve our knowledge about the natural history of the disease, the phenotype prediction and the patients' management, allowing a better evaluation of risks and benefits of the newborn screening for Fabry disease.

Light and Shadows in Newborn Screening for Lysosomal Storage Disorders: Eight Years of Experience in Northeast Italy.

In the last two decades, the development of high-throughput diagnostic methods and the availability of effective treatments have increased the interest in newborn screening for lysosomal storage disorders. However, long-term follow-up experience is needed to clearly identify risks, benefits and challenges. We report our 8-year experience of screening and follow-up on about 250,000 neonates screened for four lysosomal storage diseases (Pompe disease, mucopolysaccharidosis type I, Fabry disease, Gaucher disease), using the enzyme activity assay by tandem mass spectrometry, and biomarker quantification as a second-tier test. Among the 126 positive newborns (0.051%), 51 infants were confirmed as affected (positive predictive value 40%), with an overall incidence of 1:4874. Of these, three patients with infantile-onset Pompe disease, two with neonatal-onset Gaucher disease and four with mucopolysaccharidosis type I were immediately treated. Furthermore, another four Gaucher disease patients needed treatment in the first years of life. Our study demonstrates the feasibility and effectiveness of newborn screening for lysosomal storage diseases. Early diagnosis and treatment allow the achievement of better patient outcomes. Challenges such as false-positive rates, the diagnosis of variants of uncertain significance or late-onset forms and the lack of treatment for neuronopathic forms, should be addressed.

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.

Abnormal activation of MAPKs pathways and inhibition of autophagy in a group of patients with Zellweger spectrum disorders and X-linked adrenoleukodystrophy.

BACKGROUND: Zellweger spectrum disorders (ZSD) and X-linked adrenoleukodystrophy (X-ALD) are inherited metabolic diseases characterized by dysfunction of peroxisomes, that are essential for lipid metabolism and redox balance. Oxidative stress has been reported to have a significant role in the pathogenesis of neurodegenerative diseases such as peroxisomal disorders, but little is known on the intracellular activation of Mitogen-activated protein kinases (MAPKs). Strictly related to oxidative stress, a correct autophagic machinery is essential to eliminated oxidized proteins and damaged organelles. The aims of the current study are to investigate a possible implication of MAPK pathways and autophagy impairment as markers and putative therapeutic targets in X-ALD and ZSDs. METHODS: Three patients with ZSD (2 M, 1 F; age range 8-17 years) and five patients with X-ALD (5 M; age range 5- 22 years) were enrolled. A control group included 6 healthy volunteers. To evaluate MAPKs pathway, p-p38 and p-JNK were assessed by western blot analysis on peripheral blood mononuclear cells. LC3II/LC3I ratio was evaluated ad marker of autophagy. RESULTS: X-ALD and ZSD patients showed elevated p-p38 values on average 2- fold (range 1.21- 2.84) and 3.30-fold (range 1.56- 4.26) higher when compared with controls, respectively. p-JNK expression was on average 12-fold (range 2.20-19.92) and 2.90-fold (range 1.43-4.24) higher in ZSD and X-ALD patients than in controls. All patients had altered autophagic flux as concluded from the reduced LC3II/I ratio. CONCLUSIONS: In our study X-ALD and ZSD patients present an overactivation of MAPK pathways and an inhibition of autophagy. Considering the absence of successful therapies and the growing interest towards new therapies with antioxidants and autophagy inducers, the identification and validation of biomarkers to monitor optimal dosing and biological efficacy of the treatments is of prime interest.