Pathogenic Potential of a PCK1 Gene Variant in Cytosolic PEPCK Deficiency: A Compelling Case Study.

BACKGROUND Cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C) deficiency is an extremely rare autosomal recessive inherited error of metabolism in which gluconeogenesis is impaired, resulting in life-threatening episodes of hypoglycemia and metabolic acidosis. The diagnosis of gluconeogenesis disorders is challenging. In the diagnostic pathway, the molecular test plays a paramount role. CASE REPORT The aim of the paper is to present the case report of a girl with recurrent episodes of severe hypoglycemia, in whom molecular diagnosis enabled the confirmation of PEPCK - C deficiency. The patient experienced 4 episodes of severe hypoglycemia. Most of them were accompanied by hyperlacticaemia, metabolic acidosis, and elevated liver enzymes. All of the metabolic decompensations were triggered by infectious agents. The episodes resolved after continuous infusion of high-dose glucose. Due to the recurrent character of the disease, a genetic condition was suspected. The differential diagnosis included metabolic and endocrinological causes of hypoglycemia. Two variants in the PCK1 gene were detected: c.265G>A p.(Glu89Lys) in exon 3 and c.925G>A p.(Gly309Arg) in exon 6. As c.925G>A p.(Gly309Arg) is a known pathogenic variant, the second variant was first described in June 2023 in the ClinVar database and described as "with unknown clinical significance". CONCLUSIONS According to the clinical symptoms observed in the presented case, the variant c.265G>A p.(Glu89Lys) in PCK1 gene should be considered likely pathogenic. We suggest considering molecular diagnostics in every patient presented with recurrent, severe hypoglycemia with accompanying liver damage as most accurate, feasible, and reliable method.

Diagnosis and Management of Mucopolysaccharidosis Type II (Hunter Syndrome) in Poland.

Mucopolysaccharidosis type II (MPS II; also known as Hunter syndrome) is a rare, inherited lysosomal storage disease. The disease is caused by deficiency of the lysosomal enzyme iduronate-2-sulphatase (I2S) due to mutations in the IDS gene, which leads to accumulation of glycosaminoglycans (GAGs). Deficiency of I2S enzyme activity in patients with MPS II leads to progressive lysosomal storage of GAGs in the liver, spleen, heart, bones, joints, and respiratory tract. This process disturbs cellular functioning and leads to multisystemic disease manifestations. Symptoms and their time of onset differ among patients. Diagnosis of MPS II involves assessment of clinical features, biochemical parameters, and molecular characteristics. Life-long enzyme replacement therapy with idursulfase (recombinant human I2S) is the current standard of care. However, an interdisciplinary team of specialists is required to monitor and assess the patient's condition to ensure optimal care. An increasing number of patients with this rare disease reach adulthood and old age. The transition from pediatric care to the adult healthcare system should be planned and carried out according to guidelines to ensure maximum benefit for the patient.

Anthropometric Parameters in Patients with Fatty Acid Oxidation Disorders: A Case-Control Study, Systematic Review and Meta-Analysis.

This study compared the anthropometric parameters of patients with fatty acid oxidation disorders (FAOD) and healthy controls, showing an increased prevalence of abnormal body weight (overweight and obesity) in the FAOD group. First, differences in BMI, BMI percentiles and z-scores, and weight and weight percentiles were compared in a cohort of 39 patients with FAOD and 156 healthy controls, as well as between patients born before and after the introduction of a populational newborn screening programme (NBS) in 2014 in Poland. We also performed a systematic literature review yielding 12 studies mentioning anthropometric parameters in 80 FAOD patients and 121 control subjects, followed by a meta-analysis of data from 8 studies and our cohort. There were significant differences in body weight percentiles (p = 0.001), BMI (p = 0.022), BMI percentiles (p = 0.003) and BMI z-scores (p = 0.001) between FAOD patients and controls in our cohort but not between pre- and post-newborn-screening patients. The meta-analysis did not show any differences in weight and BMI in all tested subgroups, i.e., all FAOD patients vs. controls, medium-chain acyl-CoA dehydrogenase (MCADD) patients vs. controls and patients with FAOD types other than MCAD vs. controls. These results, however, should be interpreted with caution due to the overall low quality of evidence as assessed by GRADE, the small sample sizes and the significant heterogeneity of the included data.

Clinical characteristics and long-term outcomes of patients with glycogen storage disease type 1b: a retrospective multi-center experience in Poland.

Glycogen storage disease type 1b (GSD 1b) is an inherited metabolic defect caused by a deficiency of microsomal glucose-6-phosphate (G6P) transport protein across the endoplasmic reticulum membrane. Patients with GSD 1b have hypoglycemia episodes, lactate acidosis, hypertriglyceridemia, hypercholesterolemia, hyperuricemia, neutropenia and in imaging studies hepatomegaly and/or nephromegaly. The primary goals of treatment are to maintain proper blood glucose levels and to increase the number of properly functioning neutrophils. The aim of the study was a retrospective analysis of the clinical picture and treatment results of pediatric patients with type 1b glycogen storage disease from Poland. The study included 13 patients from 3 clinical centers, with a median age at diagnosis as 5 months. In 11/13 patients, the diagnosis was confirmed by molecular test, by the presence of pathogenic variants on both alleles of the SLC37A4 gene. Ten out of 13 patients developed the first symptoms in the form of severe infection (sepsis and/or pneumonia) already in the neonatal-infant period. A hypoglycemia episode was observed before diagnosis in 8/13 patients, of which 4/8 patients presented symptoms in the form of generalized relaxation and/or seizures. Two patients developed hypertension, and 4/13 required long-term treatment of inflammatory bowel disease.

Phenylketonuria Patients' and Their Caregivers' Perception of the Pandemic Lockdown: The Results of a National Online Survey.

The first pandemic lockdown dramatically impacted many aspects of everyday life, including healthcare systems. The purpose of this study was to identify problems of patients with phenylketonuria (PKU) and their parents/caregivers during that time. We aimed to analyse potential differences in the self-reported compliance and characteristics of contacts with a doctor/dietitian before and during the pandemic lockdown and the perception of access to special food and opinions on remote contacts between a particular group of respondents. All participants (n = 614) were asked to complete an online questionnaire that consisted of 31 questions on pandemic-related events and circumstances which may have directly or indirectly impacted health and treatment. The people who completed the survey were divided into three groups: parents of PKU children (n = 403), parents of PKU adults (n = 58) and PKU patients older than 16 years (n = 153). The differences among the three analysed groups were found in the number of contacts, the way of contacting a doctor/dietitian during the pandemic and satisfaction with remote contact. Caregivers of children with PKU reported better therapy compliance, more frequent contacts with specialists and more satisfaction with remote visits than adult patients. We also observed a relationship between satisfaction from remote contact and self-reported frequency of contacts with a doctor/dietitian, as well as a relationship between satisfaction from remote contact and recommended blood Phe levels reported by both patients and caregivers. Travel time exceeding three hours from the respondents' location to their doctor was associated with higher odds of their recognition of remote contact as a method of PKU treatment only in the group of caregivers. In the caregiver groups, the reported worse access to low-Phe products during the lockdown was linked to the perceived difficulty of maintaining the diet. However, such a relationship was not found among patients. In conclusion, significant differences in the perception of the pandemic lockdown and its impact on health and treatment-related issues were found.

COVID-19 Pandemic and Patients with Rare Inherited Metabolic Disorders and Rare Autoinflammatory Diseases-Organizational Challenges from the Point of View of Healthcare Providers.

COVID-19 pandemic is an organisational challenge for both healthcare providers and patients. People with rare inherited metabolic disorders (IMD) and rare autoinflammatory diseases (AD) are vulnerable patients whose well-being is deeply connected with regular follow-ups. This study aimed to assess how e one year of coronavirus pandemic has impacted the treatment of patients with IMD and AD in Poland. Surveys were distributed to all healthcare providers that coordinate the treatment of IMD and AD patients. Thirty-two responders (55%) answered the survey. They provide care to 1726 patients with IMD/AD, including 246 patients on dedicated treatment. In 35% of units, the regular appointments were disrupted, primarily because of patient infection. In 18 hospitals, remote visits were implemented, but only 66.6% of patients used this form of consultation. In 14/32 hospitals, administration of the therapy was delayed (median: 17.4 days). Forty-four patients suffered from SARS-COV-2 infection, in majority with mild symptoms. However, four adult patients developed complications, and one died following a SARS-COV-2 infection. Although most hospitals managed to maintain regular visits during the pandemic, more comprehensive implementation of telemedicine and switch to oral therapy or home infusions would be a reasonable solution for the current epidemic situation.

Helicobacter pylori Infection in Children with Phenylketonuria Does Not Depend on Metabolic Control and Is Not More Frequent Than in Healthy Subjects-A Cross-Sectional Study.

In a small preliminary study, phenylketonuria and poor metabolic control were suggested as risk factors for Helicobacter pylori infection in children as detected with an antigen stool test. We aimed to determine Helicobacter pylori prevalence in an adequately sized group of individuals with phenylketonuria and healthy subjects using the standard gold test (urea breath test). Further, we correlated Helicobacter pylori infection with metabolic control. The study comprised 103 individuals with phenylketonuria and 103 healthy subjects on whom a 13C urea breath test was performed. Blood phenylalanine levels in the preceding year were analysed. The infection rate did not differ between individuals with phenylketonuria and healthy subjects (10.7% vs 15.5%; p = 0.41). The frequency of testing and phenylalanine concentrations of Helicobacter pylori-positive and Helicobacter pylori-negative patients with phenylketonuria did not differ (p = 0.92 and p = 0.54, respectively). No associations were detected for body mass index or metabolic control. Forward stepwise regression models revealed that age (p = 0.0009-0.0016) was the only independent correlate of Helicobacter pylori infection with a relatively low fraction of the variability of the condition being explained (adjR2 = 0.0721-0.0754; model p = 0.020-0.023). In conclusion, Helicobacter pylori infection in phenylketonuria is not more frequent than in the general population. Moreover, it does not depend on metabolic control.

The Impact of the First 2020 COVID-19 Lockdown on the Metabolic Control of Patients with Phenylketonuria.

The present study assessed patients' metabolic control of phenylketonuria (PKU) during the first 2020 COVID-19 lockdown in Poland. Blood (phenylalanine) Phe results of the tests of 535 patients, performed in 2019 and in the first months of 2020, were analysed. The six-week lockdown period was compared to the preceding six-week period as well as to the two corresponding periods of 2019 (three non-lockdown periods). More patients failed to perform Phe tests in the lockdown period (32.7%) than in non-lockdown periods (15.6%, 15.1%, 17.2%; p < 0.001 for all). The median Phe levels for those patients who performed testing in all the four periods did not differ between periods. However, these patients tended to perform only one test during the lockdown (ORs: 1.43 to 1.60; 95% CI: from 1.01-2.04 to 1.11-2.30, p-value 0.02 to 0.005). Patients who did not take blood during the lockdown (46.7%) performed significantly fewer blood tests in the remaining periods (median : 1 <0-1> vs. 2 <1-4>; p < 0.001). In conclusion, direct assessment of patients' compliance based upon Phe levels during the pandemic lockdown was not possible. Pre-pandemic non-compliant patients frequently failed to perform the test during the lockdown, whereas the previously compliant ones were more likely to perform only one test. This strongly suggests that metabolic control might have worsened.

The Impact of the COVID-19 Pandemic on the Perception of Health and Treatment-Related Issues among Patients with Phenylketonuria in Poland-The Results of a National Online Survey.

There is agreement that the pandemic has affected the healthcare system and behaviour of patients. This study aims to identify problems encountered by patients with phenylketonuria (PKU) and their parents/caregivers during the six-week pandemic lockdown in Poland (15 March to 30 April 2020). To determine the factors that influenced health and treatment-related issues, as well as the respondents' perception of the impact of the pandemic, study participants were asked to complete a non-validated online questionnaire comprising 31 questions (including 27 single-choice, two multiple-choice and two open-ended ones). A total of 571 patients or their parents completed the questionnaire, with 9.5% of respondents not performing any blood phenylalanine (Phe) test in the analysed period, 21.3% declaring a blood Phe increase, and 15.3% a decrease. Increased problems in contacting the doctor or dietitian were reported by 26.1% of subjects, whereas 39.3% of them felt restricted access to dietary products. Most (63.4%) participants were satisfied with remote contact with their PKU clinic. Better compliance was associated with higher odds of acceptance of remote contact and of reporting fewer problems with contacting the doctor, and with lower odds of missing Phe testing. Self-reported high stress was associated with higher odds of reporting the limited availability of low-Phe products and Phe-free formulas, as well as with increased Phe concentrations and non-PKU-related health problems. These patients also had poor dietary compliance and experienced more problems in contacting specialists. Health and treatment-related problems experienced during the pandemic lockdown were related to a higher intensity of stress in patient's family and worse therapy compliance before the pandemic. Previous experience of remote visits resulted in a better perception of this method of contact. It seems that this form of communication should be popularized and improved to increase therapy effectiveness in case of different limitations in the future. Special attention should be paid to vulnerable patients who may be at extra risk when the provision of standard care is affected.

Vitamin K Status in Adherent and Non-Adherent Patients with Phenylketonuria: A Cross-Sectional Study.

This is the first study to evaluate vitamin K status in relation to dietary intake and phenylalanine dietary compliance in patients with phenylketonuria (PKU). The dietary and PKU formula intake of vitamin K was calculated in 34 PKU patients, with vitamin K status determined by the measurement of prothrombin induced by vitamin K absence (PIVKA-II). Blood phenylalanine concentrations in the preceding 12 months were considered. There were significantly more phenylalanine results exceeding 6 mg/dL in patients with normal PIVKA-II concentrations than in those with abnormal PIVKA-II levels (p = 0.035). Similarly, a higher total intake of vitamin K and dietary vitamin intake expressed as µg/day (p = 0.033 for both) and %RDA (p = 0.0002 and p = 0.003, respectively) was observed in patients with normal PIVKA-II levels. Abnormal PIVKA-II concentrations were associated with a lower OR (0.1607; 95%CI: 0.0273-0.9445, p = 0.043) of having a median phenylalanine concentration higher than 6 mg/dL. In conclusion, vitamin K deficiency is not uncommon in phenylketonuria and may also occur in patients with adequate vitamin K intake. PKU patients with better dietary compliance have a higher risk of vitamin K deficiency. The present findings highlight the need for further studies to re-evaluate dietary recommendations regarding vitamin K intake, both concerning formula-based and dietary consumption of natural products.

Overweight in classical phenylketonuria children: A retrospective cohort study.

PURPOSE: This cohort study aimed to determine the frequency of overweight and obesity in classical phenylketonuria children and to identify the possible influence of metabolic control on the BMI of the studied patients. PATIENTS AND METHODS: The study group included 63 classical phenylketonuria patients (40 girls and 23 boys; aged 5-16 years). Their z-score BMI, metabolic control, educational level of parents and socioeconomic status were determined. RESULTS: Twenty children were overweight or obese and only three were underweight. The percentages of overweight and obese children were 31.7% for the whole group, 21.7% (5 out of 23) for boys and 37.5% (15 out of 40) for girls. Overweight and obesity in these phenylketonuria patients was statistically significantly more frequent when compared to national reference studies (p = 0.0031). The five-year index of dietary control and the percentage of spikes exceeding 6 and 12 mg/dl (Spikes 6 and 12) indicated better metabolic control in the case of normal weight children than those who were overweight and obese (p < 0.049, p < 0.041 and p < 0.011, respectively). The odds ratio of being overweight or obese for those having poorer metabolic control (values higher vs lower than mean) was statistically significantly higher than for the remaining patients (for Spikes 12: 6.926 < 95%CI: 2.011-23.854 > ; p < 0.002). These results strongly suggest a link between overweight and diet non-compliance. CONCLUSIONS: Children with classical phenylketonuria presented higher odds of being overweight or obese as compared with reference national studies, with girls only having a higher frequency of overweight.

Therapy compliance in children with phenylketonuria younger than 5 years: A cohort study.

BACKGROUND: Phenylketonuria (PKU) is a metabolic disease. It is manifested by a complete or partial inability to convert phenylalanine (Phe) to tyrosine and leads to increased concentrations of Phe in the blood and in other tissues, including the brain, causing irreversible neurological damage if left untreated. Low-phenylalanine diet is a key component of classical PKU therapy. OBJECTIVES: The objective of this study was to assess the effectiveness of classical phenylketonuria therapy and compliance with doctors' recommendations in the first 5 years of life. MATERIAL AND METHODS: Data was collected from all diagnosed and treated patients (n = 57) born 1999-2010. Phenylalanine blood levels, the number of visits to a specialist outpatients' center, the number of blood tests, as well as socioeconomic status (SES) and parents' education level have been analyzed, and potential relationships have been assessed. RESULTS: In the 1st year of life patients visited their doctors (odds ratio (OR) = 6.8267; 95% confidence interval (95% CI) = 2.827-16.5163; p < 0.0001) and had their blood collected (OR = 2.7875; 95% CI = 1.0467-7.4234; p < 0.0402) significantly more frequently than in the 2nd year. This tendency persisted into subsequent years. Similarly, in infancy they had statistically significantly lower odds of exceeding more than 40% of their Phe levels over therapeutic range than 1 year later (OR = 3.6078; 95% CI = 1.4859-8.7599; p < 0.0046). No PKU child had more than 70% of Phe levels over the therapeutic range in the 1st year of life, whereas 4 years later there were 18 such children. Phe levels were correlated with the number of visits to a specialist (ρ = 0.39) and the number of Phe blood tests with index of dietary control (ρ = -0.33). The effectiveness of therapy and compliance with the doctor's recommendations seem to depend neither on the level of education of the patient's parents nor on their SES. CONCLUSIONS: Therapy effectiveness and patients' compliance in PKU is very good in infancy. However, both deteriorate in subsequent years. Moreover, they do not seem to depend on the family background.

Deficiency of long-chain polyunsaturated fatty acids in phenylketonuria: a cross-sectional study.

The etiology of altered blood fatty acid (FA) profile in phenylketonuria (PKU) is understood only partially. We aimed to determine whether FAs deficiency is dependent on the diet or metabolic disturbances. The study comprised 40 PKU patients (20 female, 20 male; aged 11 to 35 years; 12 children and 28 adults) and 40 healthy subjects (HS; 20 female, 20 male, aged 18 to 33 years). We assessed the profile of FAs (gas chromatography/mass spectrometry) and analyzed the 72-hour dietary recalls. The amount of C14:0, C16:0 and C16:1n-7, C18:1n-9 did not differ between the analyzed groups. The percentage of C18:0 was higher, while C20:3n-9, C18:2n-6, C20:2n-6, C20:4n-6, C22:4n-6, C22:5n-6 and C22:6n-3 was lower in PKU than in HS. However, C18:3n-6, C18:3n-3 and n-6/n-3 ratio were higher in PKU patients. The C20:4n-6/C20:3n-6 ratio (reaction catalyzed by Δ5-desaturase), the C22:5n-6/C22:4n-6 and the C22:6n-3/C22:5n-3 ratio (both reactions catalyzed by Δ6 desaturase) were significantly lower in PKU patients. Therefore, the deficiency of long-chain polyunsaturated fatty acids in PKU patients may result not only from inadequate supply but also from metabolic disturbances.

Phenylketonuria is not a risk factor for changes of inflammation status as assessed by interleukin 6 and interleukin 8 concentrations.

BACKGROUND: High oxidative stress and a reduced potential for free radical scavenging in phenylketonuria (PKU) patients, a phenomenon confirmed in a few studies, may lead to systemic chronic inflammation. The aim of this study was to compare the inflammation status, as assessed by interleukin 6 and interleukin 8 concentrations, in patients with PKU and in healthy controls. METHODS: Twenty patients with classical PKU, aged 18-34 years and under dietary control, were enrolled in the study. The control group comprised of 20 healthy subjects matched for age and sex. Interleukin 6 and 8 levels were measured by enzyme-linked immunosorbent assay (ELISA) kits in all study participants. RESULTS: IL-6 concentrations in the study group ranged from 0.74 pg/ml to 1.34 pg/ml. No significant differences were found between IL-6 concentration between the study group and the control group (p = 0.989). IL-8 concentrations ranged from 17.56 pg/ml to 20.87 pg/ml. The obtained results of IL-8 levels did not differ significantly between the study group and control group (p = 0.192). No significant correlation was observed between Phe blood levels and IL-6 or IL-8 concentrations in the study group (ρ respectively: -0.225, 0.177). In a multivariate analysis, neither IL-6 nor IL-8 concentrations were correlated with sex, age, BMI and Phe levels. CONCLUSIONS: Phenylketonuria is not a risk factor for changes of inflammation status as assessed by IL-6 and IL-8 concentrations.

Molecular genetics of PKU in Poland and potential impact of mutations on BH4 responsiveness.

Tetrahydrobiopterin (BH4) has been recently approved as a treatment of patients with phenylketonuria. However, as a confirmation of BH4-responsiveness, it might require a very expensive trial treatment with BH4 or prolonged BH4-loading procedures. The selection of patients eligible for BH4-therapy by means of genotyping of the PAH gene mutations may be recommended as a complementary approach. A population-wide genotyping study was carried out in 1286 Polish phenyloketonuria-patients. The aim was to estimate the BH4 demand and to cover prospectively the treatment by a National Health Fund. A total of 95 types of mutations were identified. Genetic variants corresponding with probable BH4-responsiveness were found in 28.2% of cases. However, patients with mild or classical phenylketonuria who require continuous treatment accounted for 11.4% of the studied population only. Analysis of the published data shows similar percentage of the "BH4-responsive" variants of a PAH gene in patients from other countries of Eastern Europe. Therefore, it can be concluded, that the proportion of phenylketonuria-patients who could benefit from the use of BH4 reaches approximately 10% in the entire region.