An NMR-based metabolic signature to identify clinically significant prostate cancer in patients undergoing biopsy.

CONTEXT: Despite clinical suspicion of prostate cancer (PCa), 20-25% of patients exhibit a tumor-negative biopsy result. OBJECTIVE: To assess the serum metabolic profile of clinically significant (cs) compared to clinically insignificant (ci) PCa or benign (Be) patients. STUDY DESIGN: 1078 serum samples were analyzed. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Nuclear magnetic resonance (NMR) spectroscopy was used to quantify 73 metabolites, Random Forest for model algorithm. RESULTS: We identified a 22-metabolite panel, which discriminated csPCa (ISUP 2-5, n=328) from ciPCa (ISUP 1, n=101) and benign patients (negative biopsy, n=649) with a higher performance when combined with the standard clinical parameters age, prostate specific antigen (PSA), and percentage free PSA (%fPSA) (AUC 0.84) than the clinical parameters alone (AUC 0.73). Our study further revealed significant dysregulations of the urea cycle and the choline pathway along with changes in tricarboxylic acid (TCA) cycle, cholesterol metabolism, and a significant increase of the inflammation marker GlycB in csPCa patients. In particular, ornithine and dimethylglycine were the 2 most important features to discriminate csPCa from Be+ciPCa with significantly higher ornithine and lower dimethylglycine levels in patients with csPCa (ornithine: 63.7 ± 26.5 µmol/l, dimethylglycine: 12.6 ± 6.3 µmol/l, p<0.001) compared to Be+ciPCa patients (ornithine: 50.3 ± 31.6 µmol/l, dimethylglycine: 14.9 ± 7.7 µmol/l). CONCLUSIONS: This study discovered a 22-metabolite panel to discriminate patients with csPCa from Be+ciPCa patients when combined with age, PSA, and %fPSA. It may therefore be used as supportive biomarker to reduce the number of unnecessary biopsies and also to identify novel therapeutic targets in the future.

Arabidopsis thaliana argininosuccinate lyase structure uncovers the role of serine as the catalytic base.

Arginine is an important amino acid in plants, as it not only plays a structural role and serves as nitrogen storage but is also a precursor for various molecules, including polyamines and proline. Arginine is produced by argininosuccinate lyase (ASL) which catalyzes the cleavage of argininosuccinate to arginine and fumarate. ASL belongs to the fumarate lyase family and while many members of this family were well-characterized, little is known about plant ASLs. Here we present the first crystal structures of ASL from the model plant, Arabidopsis thaliana (AtASL). One of the structures represents the unliganded form of the AtASL homotetramer. The other structure, obtained from a crystal soaked in argininosuccinate, accommodates the substrate or the reaction products in one of four active sites of the AtASL tetramer. Each active site is located at the interface of three neighboring protomers. The AtASL structure with ligands allowed us to analyze the enzyme-substrate and the enzyme-product interactions in detail. Furthermore, based on our analyses, we describe residues of AtASL crucial for catalysis. The structure of AtASL gives the rationale for the open-to-close transition of the GSS mobile loop and indicates the importance of serine 333 from this loop for the enzymatic action of the enzyme. Finally, we supplemented the structural data with the identification of sequence motifs characteristic for ASLs.

Management of a urea cycle disorder in the setting of socioeconomic and language barriers.

Argininosuccinic aciduria (ASA) is a disorder that results from a deficiency in the urea cycle enzyme argininosuccinate lyase. Variable manifestations of this hereditary disorder are associated with hyperammonemia and can include lethargy, somnolence, and respiratory alkalosis in neonates, and vomiting, headaches, and neurocognitive deficiencies later in life. Management of ASA includes rapid measures to address hyperammonemia and long-term steps to maintain metabolic stability. Management paradigms should also consider social determinants of health, which are non-medical factors that influence health outcomes. Here, we describe the case of a male pediatric patient with ASA whose treatment has included considerations for his family's refugee status, language barriers, cultural adjustments, limited income, and transportation challenges.

Treating the whole patient: Facilitating health care for patients facing health inequity.

Social determinants of health (SDOH) are conditions in which people are born, grow, live, work, and age. Variations in these conditions are largely responsible for health inequities, the differences in health status or distribution of health resources within a population. Despite recent increases in attention to SDOH in research and clinical practice, few, if any, resources exist to describe how these complex dynamics impact patients with inborn errors of metabolism. Recognizing the role real-life narratives have as a powerful educational tool, we compiled a series of 3 original cases, published as part of this special supplement, to illustrate challenges and learnings related to SDOH within the context of urea cycle disorders and phenylketonuria.

Fatal consequences of limited health literacy in a patient with a rare metabolic disease.

A Black young adult female diagnosed with argininosuccinate lyase deficiency at 6 months of age encountered significant barriers to care for the first 16 years of her life due to socioeconomic factors and parental neglect. Once in the care of her paternal grandmother, she received appropriate treatment with a nitrogen scavenger, amino acid supplementation, and a low-protein diet. However, due to repeated hyperammonemic crises early in her life, she was minimally communicative and unable to perform activities of daily living. During her final hyperammonemic crisis, she presented to a hospital unfamiliar with urea cycle disorders and without a metabolic service. As a result, she did not receive optimal care and died.

Determination of the Protein and Amino Acid Content of Fruit, Vegetables and Starchy Roots for Use in Inherited Metabolic Disorders.

Amino acid (AA)-related inherited metabolic disorders (IMDs) and urea cycle disorders (UCDs) require strict dietary management including foods low in protein such as fruits, vegetables and starchy roots. Despite this recommendation, there are limited data on the AA content of many of these foods. The aim of this study is to describe an analysis of the protein and AA content of a range of fruits, vegetables and starchy roots, specifically focusing on amino acids (AAs) relevant to AA-related IMDs such as phenylalanine (Phe), methionine (Met), leucine (Leu), lysine (Lys) and tyrosine (Tyr). AA analysis was performed using high-performance liquid chromatography (HPLC) on 165 food samples. Protein analysis was also carried out using the Dumas method. Foods were classified as either 'Fruits', 'Dried fruits', 'Cruciferous vegetables', 'Legumes', 'Other vegetables' or 'Starchy roots'. 'Dried fruits' and 'Legumes' had the highest median values of protein, while 'Fruits' and 'Cruciferous vegetables' contained the lowest median results. 'Legumes' contained the highest and 'Fruits' had the lowest median values for all five AAs. Variations were seen in AA content for individual foods. The results presented in this study provide useful data on the protein and AA content of fruits, vegetables and starchy roots which can be used in clinical practice. This further expansion of the current literature will help to improve diet quality and metabolic control among individuals with AA-related IMDs and UCDs.

Redox remodeling of central metabolism as a driving force for cellular protection, proliferation, differentiation, and dysfunction.

The production of reactive oxygen species (ROS) is elevated via metabolic hyperactivation in response to a variety of stimuli such as growth factors and inflammation. Tolerable amounts of ROS moderately inactivate enzymes via oxidative modification, which can be reversed back to the native form in a redox-dependent manner. The excessive production of ROS, however, causes cell dysfunction and death. Redox-reactive enzymes are present in primary metabolic pathways such as glycolysis and the tricarboxylic acid cycle, and these act as floodgates for carbon flux. Oxidation of a specific form of cysteine inhibits glyceraldehyde-3-phosphate dehydrogenase, which is reversible, and causes an accumulation of upstream intermediary compounds that increases the flux of glucose-6-phosphate to the pentose phosphate pathway. These reactions increase the NADPH and ribose-5-phosphate that are available for reductive reactions and nucleotide synthesis, respectively. On the other hand, oxidative inactivation of mitochondrial aconitase increases citrate, which is then recruited to synthesize fatty acids in the cytoplasm. Decreases in the use of carbohydrate for ATP production can be compensated via amino acid catabolism, and this metabolic change makes nitrogen available for nucleic acid synthesis. Coupling of the urea cycle also converts nitrogen to urea and polyamine, the latter of which supports cell growth. This metabolic remodeling stimulates the proliferation of tumor cells and fibrosis in oxidatively damaged tissues. Oxidative modification of these enzymes is generally reversible in the early stages of oxidizing reactions, which suggests that early treatment with appropriate antioxidants promotes the maintenance of natural metabolism.

In-depth analysis of OTC A208T case induced by OTC gene mutation and research on the prediction and simulation of the impact on protein function.

Background: Ornithine transcarbamylase deficiency (OTCD), a rare hereditary disease caused by gene mutation of ornithine transcarbamylase (OTC), is the most prevalent type among urea cycle disorders. OTCD typically leads to mitochondrial enzyme dysfunction, preventing the synthesis of citrulline from carbamoyl phosphate and ornithine, and is characterized by a remarkable increase in blood ammonia. Specific symptoms may include neurological abnormalities, growth retardation, and other manifestations. Methods: We presented a case of a child diagnosed with OTCD (OMIM: 311250). By using whole-genome sequencing (WGS) for the pedigree and in-depth whole-exome sequencing (WES), we aimed to identify the disease-causing genes. Gene mutation prediction tools were employed to verify the pathogenicity, and the molecular dynamics simulation method was utilized to assess the impact of this mutation on the activity and structural stability of the OTC protein. Results: Whole-exome sequencing detected an OTC variant [NM_000531: c.622 (exon6) G > A, p.A208T]. Through comprehensive analysis with various gene mutation prediction tools and in line with the ACMG guidelines, this mutation site was firmly established as a pathogenic site. Moreover, the molecular dynamics simulation results clearly demonstrated that this mutation would significantly compromise the stability of the OTC protein structure. Conclusion: This study deepens our understanding of the clinical manifestations and characteristics of OTCD, especially the OTC A208T gene mutation site. Given the lack of specific clinical manifestations in OTCD patients, early and accurate diagnosis is crucial for effective treatment and prognosis improvement. To our knowledge, this is the first case of this mutation site reported in China.

Perioperative Management of Argininemia Child Undergoing Circumcision: A Case Report.

Argininemia is a rare autosomal recessive metabolic disorder characterized by a deficiency of arginase, a vital enzyme in the urea cycle. This metabolic defect results in the accumulation of arginine and its metabolites, leading to hyperammonemia and associated neurological symptoms. We present a case detailing the perioperative management of an 11-year-old male child diagnosed with argininemia undergoing circumcision. The perioperative management of patients with argininemia presents unique challenges due to the risk of hyperammonemia and neurological decompensation triggered by physiological stress, fasting, and the catabolic state associated with surgery. This case report highlights the importance of individualized anesthetic strategies for patients with rare metabolic disorders like argininemia. A multidisciplinary approach involving collaboration among anesthesiologists, endocrinologists, dietitians, and surgeons is essential to ensuring a safe perioperative experience for these patients. Further research is essential to refine perioperative protocols and optimal anesthetic interventions for individuals with argininemia undergoing surgical procedures.

A preliminary retrospective evaluation of screening and diagnosis of ornithine transcarbamylase deficiency in high-risk patients at a referral center in Vietnam.

Introduction: To date, newborn screening (NBS) for proximal urea cycle disorders, including Ornithine transcarbamylase deficiency (OTCD), was not recommended due to the lack of appropriate tests and insufficient evidence of the benefits. This study aimed to investigate the potential of tandem mass spectrometry (MS/MS) for OTCD screening and its value in guiding further investigation to obtain a final diagnosis in high-risk patients. Methods: The study included patients with OTCD referred to the National Children's Hospital between April 2020 and November 2023. A retrospective evaluation of amino acid concentrations measured by MS/MS and their ratios in patients with early-onset and late-onset OTCD was conducted. Results: While all ten early-onset cases had glutamine concentrations above the upper limit, only five of them had citrulline concentrations below the lower limit of the reference interval. Only two late-onset cases had elevated glutamine levels, while all had citrulline within reference intervals. The Cit/Phe ratio was decreased, and the Gln/Cit and Met/Cit ratios were increased in all early-onset OTCD cases, while they were abnormal in only one late-onset case. Conclusions: The preliminary results suggest that hyperglutaminemia, in combination with low or normal citrulline concentrations and specific ratios (Gln/Cit, Met/Cit, and Cit/Phe), can serve as reliable markers for screening early-onset OTCD in high-risk patients. However, these markers proved less sensitive for detecting the late-onset form, even in symptomatic patients.

Neonatal Presentation of Ornithine Transcarbamylase Deficiency Associated With a Hypomorphic OTC Variant (p.Leu301Phe) Previously Reported in Later-Onset Disease.

Ornithine transcarbamylase deficiency (OTCD) is the most common subtype of urea cycle disorders. Caused by mutations in the X-linked gene OTC,it often leads to hyperammonemia which can result in neurotoxicity, coma, and death. We describe the clinical course of a male newborn known to carry a hypomorphic variant (p.Leu301Phe) in OTC previously reported in cases with later-onset OTCD. Despite being clinically asymptomatic, our affected patient presented with hyperammonemia in the neonatal period. Oral feedings were temporarily discontinued, and low protein medical formula and ammonia scavenger medications were initiated to normalize ammonia levels. This case supports the pathogenicity of the reported OTC gene variant and early presentation that necessitates disease-specific management. Our report will help provide guidance surrounding the most appropriate management of future patients with this variant as they will likely require management in the newborn period.

Severity-adjusted evaluation of initial dialysis on short-term health outcomes in urea cycle disorders.

OBJECTIVE: In individuals with urea cycle disorders (UCDs) and neonatal disease onset, extracorporeal detoxification by continuous kidney replacement therapy is considered the therapeutic method of choice in addition to metabolic emergency treatment to resolve hyperammonemic decompensation. However, the indications for the initiation of dialysis are heterogeneously implemented transnationally, thereby hampering our understanding of (optimal) short-term health outcomes. METHODS: We performed a retrospective comparative analysis evaluating the therapeutic effects of initial dialysis on survival as well as neurocognitive outcome parameters in individuals with UCDs in comparison to a severity-adjusted non-dialyzed control cohort. Overall, 108 individuals with a severe phenotype of male ornithine transcarbamylase deficiency (mOTC-D), citrullinemia type 1 (CTLN1) and argininosuccinic aciduria (ASA) were investigated by stratification based on a recently established and validated genotype-specific disease prediction model. RESULTS: Mortality is associated with the height of initial peak plasma ammonium concentration, but appears to be independent from treatment with initial dialysis in mOTC-D. However, improved survival after initial dialysis was observed in CTLN1, while there was a trend towards improved survival in ASA. In survivors, annual frequency of (subsequent) metabolic decompensations did not differ between the dialyzed and non-dialyzed cohorts. Moreover, treatment with initial dialysis was not associated with improved neurocognitive outcomes. INTERPRETATION: The present severity-adjusted comparative analysis reveals that general practice of initial dialysis is neither associated with improved survival in individuals with mOTC-D nor does it differ with regard to the neurocognitive outcome for the investigated UCD subtypes. However, initial dialysis might potentially prove beneficial for survival in CTLN1 and ASA. CLINICAL TRIAL REGISTRATION: The UCDC database is recorded at the US National Library of Medicine (https://clinicaltrials.gov).

Clinical characteristics and molecular genetic analysis of ten cases of ornithine carbamoyltransferase deficiency in southeastern China.

BACKGROUND: This study aimed to investigate the clinical and molecular genetic characteristics of ten children with ornithine carbamoyltransferase deficiency (OTCD) in southeastern China, as well as the correlation between the genotype and phenotype of OTCD. METHODS: A retrospective analysis was performed on the clinical manifestations, laboratory testing, and genetic test findings of ten children with OTCD admitted between August 2015 and October 2021 at Quanzhou Maternity and Children's Hospital of Fujian Province in China. RESULTS: Five boys presented with early-onset symptoms, including poor appetite, drowsiness, groaning, seizures, and liver failure. In contrast, five patients (one boy and four girls) had late-onset gastrointestinal symptoms as the primary clinical manifestation, all presenting with hepatic impairment, and four with hepatic failure.Nine distinct variants of the OTC gene were identified, including two novel mutations: c.1033del(p.Y345Tfs*50) and c.167T > A(p.M56K). Of seven patients who died, five had early-onset disease despite active treatment. Three patients survived, and two of them underwent liver transplantation. CONCLUSIONS: The clinical manifestations of OTCD lack specificity. However, elevated blood ammonia levels serve as a crucial diagnostic clue for OTCD. Genetic testing aids in more accurate diagnosis and prognosis assessment by clinicians. In addition, we identified two novel pathogenic variants and expand the mutational spectrum of the gene OTC, which may contribute to a better understanding of the clinical and genetic characteristics of OTCD patients.

Hierarchical tricarboxylic acid cycle regulation by hepatocyte arginase 2 links the urea cycle to oxidative metabolism.

Urea cycle impairment and its relationship to obesity and inflammation remained elusive, partly due to the dramatic clinical presentation of classical urea cycle defects. We generated mice with hepatocyte-specific arginase 2 deletion (Arg2LKO) and revealed a mild compensated urea cycle defect. Stable isotope tracing and respirometry revealed hepatocyte urea and TCA cycle flux defects, impaired mitochondrial oxidative metabolism, and glutamine anaplerosis despite normal energy and glucose homeostasis during early adulthood. Yet during middle adulthood, chow- and diet-induced obese Arg2LKO mice develop exaggerated glucose and lipid derangements, which are reversible by replacing the TCA cycle oxidative substrate nicotinamide adenine dinucleotide. Moreover, serum-based hallmarks of urea, TCA cycle, and mitochondrial derangements predict incident fibroinflammatory liver disease in 106,606 patients nearly a decade in advance. The data reveal hierarchical urea-TCA cycle control via ARG2 to drive oxidative metabolism. Moreover, perturbations in this circuit may causally link urea cycle compromise to fibroinflammatory liver disease.

Novel therapeutic targets: bifidobacterium-mediated urea cycle regulation in colorectal cancer.

BACKGROUND AND PURPOSE: Colorectal cancer (CRC) is a widespread malignancy with a complex and not entirely elucidated pathogenesis. This study aims to explore the role of Bifidobacterium in the urea cycle (UC) and its influence on the progression of CRC, a topic not extensively studied previously. EXPERIMENTAL APPROACH: Utilizing both bioinformatics and experimental methodologies, this research involved analyzing bacterial abundance in CRC patients in comparison to healthy individuals. The study particularly focused on the abundance of BA. Additionally, transcriptomic data analysis and cellular experiments were conducted to investigate the impact of Bifidobacterium on ammonia metabolism and mitochondrial function, specifically examining its regulation of the key UC gene, ALB. KEY RESULTS: The analysis revealed a significant decrease in Bifidobacterium abundance in CRC patients. Furthermore, Bifidobacterium was found to suppress ammonia metabolism and induce mitochondrial dysfunction through the regulation of the ALB gene, which is essential in the context of UC. These impacts contributed to the suppression of CRC cell proliferation, a finding corroborated by animal experimental results. CONCLUSIONS AND IMPLICATIONS: This study elucidates the molecular mechanism by which Bifidobacterium impacts CRC progression, highlighting its role in regulating key metabolic pathways. These findings provide potential targets for novel therapeutic strategies in CRC treatment, emphasizing the importance of microbiota in cancer progression.

A Novel Mutation of ORNT1 Detected in a Hyperornithinemia-Hyperammonemia-Homocitrullinuria Syndrome Child by Clinical Whole-Exome Sequencing.

Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome, an inborn error of metabolism, is an inherited syndrome caused by loss-of-function mutations in the SLC25A15, resulting in ornithine translocase1 (ORNT1) deficiency. Disrupted ornithine transportation in an affected individual usually manifests with the accumulation of intermediate metabolites, leading to neurological impairment, hepatitis, and/or protein intolerance at various ages of onset. In this paper, we report a compound heterozygous mutation in SLC25A15 from a 2-year-old girl who presented with neurological alterations and hepatic failure. Before developing neurological sequelae, she had signs of globally delayed development. The accumulation of toxic metabolites may explain these neurological consequences. After biochemical confirmation of HHH, whole-exome sequencing (WES) was performed, which identified mutations at codons 21 and 179 of SLC25A15 that are predicted to result in the loss of function of ORNT1. Each of the mutations was found to be inherited from one of her parents. After therapy, her toxic metabolites decreased significantly. In conclusion, HHH syndrome frequently manifests with nonspecific symptoms and unapparent biochemical profiles, which may lead to delayed diagnosis. Correction of the accumulating metabolites is necessary to prevent irreversible neurological impairment. Furthermore, performing a WES provides a shortcut for accurate diagnosis.

Seizure Characteristics and EEG Features in Intoxication Type and Energy Deficiency Neurometabolic Disorders in the Pediatric Intensive Care Unit: Single-Center Experience Over 10 Years.

BACKGROUND: Acute metabolic crises in inborn errors of metabolism (such as urea cycle disorders, organic acidemia, maple syrup urine disease, and mitochondrial disorders) are neurological emergencies requiring management in the pediatric intensive care unit (PICU). There is a paucity of data pertaining to electroencephalograms (EEG) characteristics in this cohort. We hypothesized that the incidence of background abnormalities and seizures in this cohort would be high. Neuromonitoring data from our center's PICU over 10 years are presented in this article. METHODS: Data were collected by retrospective chart review for patients with the aforementioned disorders who were admitted to the PICU at our institution because of metabolic/neurologic symptoms from 2008 to 2018. Descriptive statistics (χ2 test or Fisher's exact test) were used to study the association between EEG parameters and outcomes. RESULTS: Our cohort included 40 unique patients (8 with urea cycle disorder, 7 with organic acidemia, 3 with maple syrup urine disease, and 22 with mitochondrial disease) with 153 admissions. Presenting symptoms included altered mentation (36%), seizures (41%), focal weakness (5%), and emesis (28%). Continuous EEG was ordered in 34% (n = 52) of admissions. Twenty-three admissions were complicated by seizures, including eight manifesting as status epilepticus (seven nonconvulsive and one convulsive). Asymmetry and focal slowing on EEG were associated with seizures. Moderate background slowing or worse was noted in 75% of EEGs. Among those patients monitored on EEG, 4 (8%) died, 3 (6%) experienced a worsening of their Pediatric Cerebral Performance Category (PCPC) score as compared to admission, and 44 (86%) had no change (or improvement) in their PCPC score during admission. CONCLUSIONS: This study shows a high incidence of clinical and subclinical seizures during metabolic crisis in patients with inborn errors of metabolism. EEG background features were associated with risk of seizures as well as discharge outcomes. This is the largest study to date to investigate EEG features and risk of seizures in patients with neurometabolic disorders admitted to the PICU. These data may be used to inform neuromonitoring protocols to improve mortality and morbidity in inborn errors of metabolism.

Biotechnological application of Aureobasidium spp. as a promising chassis for biosynthesis of ornithine-urea cycle-derived bioproducts.

The ornithine-urea cycle (OUC) in fungal cells has biotechnological importance and many physiological functions and is closely related to the acetyl glutamate cycle (AGC). Fumarate can be released from argininosuccinate under the catalysis of argininosuccinate lyase in OUC which is regulated by the Ca2+ signaling pathway and over 93.9 ± 0.8 g/L fumarate can be yielded by the engineered strain of Aureobasidium pullulans var. aubasidani in the presence of CaCO3. Furthermore, 2.1 ± 0.02 mg of L-ornithine (L-Orn)/mg of the protein also can be synthesized via OUC by the engineered strains of Aureobasidum melanogenum. Fumarate can be transformed into many drugs and amino acids and L-Orn can be converted into siderophores (1.7 g/L), putrescine (33.4 g/L) and L-piperazic acid (L-Piz) (3.0 g/L), by different recombinant strains of A. melanogenum. All the fumarate, L-Orn, siderophore, putrescine and L-Piz have many applications. As the yeast-like fungi and the promising chassis, Aureobasidium spp, have many advantages over any other fungal strains. Further genetic manipulation and bioengineering will enhance the biosynthesis of fumarate and L-Orn and their derivates.

OUC in fungal cells has biotechnological importance and many physiological functions; OUC is closely related to acetyl glutamate cycle (AGC). Fumarate, L-Orn, siderophore, putrescine and L-Piz produced from OUC have many applications.

Long-term neurodevelopmental outcomes following liver transplantation for metabolic disease-a single centre experience.

This study describes the neurodevelopmental outcome of children with urea cycle disorders (UCD) and organic acidemias (OA) preliver transplant (LT), 1-year, and 3-years post-LT. We performed a retrospective chart review of children with OA or UCD transplanted between January 2014 and December 2021. Standardized motor and cognitive assessment scores were collected from children who had ≥1 motor/cognitive assessment at any timepoint. Pre-LT brain magnetic resonance imaging (MRI) was graded. Associations between demographic/medical variables and neurodevelopmental outcomes were explored. Twenty-six children (64% male) underwent LT at a median age of 1.4 (interquartile range 0.71, 3.84) years. Fifteen (58%) had a UCD diagnosis, 14 (54%) required dialysis for hyperammonemia, and 10 (42%) had seizures typically around diagnosis. The proportion of children with gross motor scores >1 standard deviation (SD) below the mean increased across timepoints, and ≥50% demonstrated general intellect scores >2 SD below the mean at each timepoint. The following significant associations were noted: UCD diagnoses with lower general intellect scores (p = 0.019); arginosuccinate lyase deficiency diagnosis with lower visual motor scores at 3-years post-LT (p = 0.035); a history of seizures pre-LT with lower general intellect (>2SD below the mean) at 3-years post-LT (p = 0.020); dialysis pre-LT with lower motor scores (>1 SD below the mean) at 1-year post-LT (p = 0.039); pre-emptive LT with higher general intellect scores at 3-years post-LT (p = 0.001). MRI gradings were not associated with developmental scores. In our single centre study, children with UCD or OA had a higher prevalence of developmental impairment post-LT compared to population norms. Earlier screening, pre-emptive transplant, and rehabilitation may optimize long-term outcomes.

Unraveling the Link: Seizure Characteristics and Ammonia Levels in Urea Cycle Disorder During Hyperammonemic Crises.

BACKGROUND: This retrospective clinical study performed at a single clinical center aimed to identify the prevalence of seizures in individuals with urea cycle disorders (UCDs) with and without hyperammonemic (HA) crises. In addition, we sought to correlate the utility of biochemical markers and electroencephalography (EEG) in detecting subclinical seizures during HA. METHODS: Medical records of individuals with UCDs enrolled in Urea Cycle Disorders Consortium Longitudinal Study (UCDC-LS) (NCT00237315) at Children's National Hospital between 2006 and 2022 were reviewed for evidence of clinical and subclinical seizuress during HA crises, and initial biochemical levels concurrently. RESULTS: Eighty-five individuals with UCD were included in the analyses. Fifty-six of the 85 patients (66%) experienced HA crises, with a total of 163 HA events. Seizures are observed in 13% of HA events. Among all HA events with concomitant EEG, subclinical seizures were identified in 27% of crises of encephalopathy without clinical seizures and 53% of crises with clinical seizures. The odds of seizures increases 2.65 (95% confidence interval [CI], 1.51 to 4.66) times for every 100 µmol/L increase in ammonia and 1.14 (95% CI, 1.04 to 1.25) times for every 100 µmol/L increase in glutamine. CONCLUSIONS: This study highlights the utility of EEG monitoring during crises for patients presenting with clinical seizures or encephalopathy with HA. During HA events, measurement of initial ammonia and glutamine can help determine risk for seizures and guide EEG monitoring decisions.