Hyperammonemic encephalopathy in a child with ornithine transcarbamylase deficiency due to a novel combined heterozygous mutations

Acute liver dysfunction with delayed peak of serum aminotransferase levels as a presentation of ornithine transcarbamylase deficiency in females

We describe 10 females with ornithine transcarbamylase (OTC) deficiency and liver dysfunction, revealing a unique pattern of hepatocyte injury in which initial hyperammonemia and coagulopathy is followed by a delayed peak in aminotransferase levels. None of the patients required urgent liver transplantation, though five eventually underwent transplant for recurrent metabolic crises. We intend that this novel observation will initiate further investigations into the pathophysiology of liver dysfunction in OTC-deficient patients, and ultimately lead to the development of therapies and prevent the need for liver transplant.

Clinical features and underlying genetic causes in neonatal encephalopathy: A large cohort study

This study aimed to investigate the potential genetic causes of neonatal encephalopathy (NE) in a large cohort of Chinese patients. We included 366 neonates with encephalopathy. Whole exome sequencing was performed to assess the potential molecular defects. In this study, 43 patients (11.7%) were identified with pathogenic or likely pathogenic variants and 10 patients (2.7%) carried variants with unknown significance. Compared with patients without genetic findings (28.9%), patients with genetic findings (96.2%) displayed a significant higher incidence of seizure (P = .0009); however, a lower frequency of abnormal magnetic resonance imaging (MRI) results (P < .0001). Epileptic encephalopathy related genes account for nearly half (46.4%) of all genetic defects of NE with seizures. Follow-up results revealed genetic diagnosis, seizure and severe abnormal electroencephalograph results were significantly associated with high risk of developmental delay (P < .05). This study increases the understanding of genetic contribution to NE. Our findings suggest that the full-term NE patients with seizure, the greater the possibility of genetic diseases. However, for newborns especially the preterm babies with abnormal MRI findings, there is smaller possibility of genetic diseases. NE caused from genetic diseases have poor prognosis, and intensive intervention and follow-up is necessary for these newborns.

Clinical and cranial MRI features of female patients with ornithine transcarbamylase deficiency: Two case reports

INTRODUCTION

Ornithine transcarbamylase deficiency (OTCD) is a common metabolic disease of urea circulation disorder. We reported the clinical, brain imaging and genetic characteristics of 2 cases with OTCD. The patients' clinical features, novel gene mutations, cranial MR specific imaging changes and blood tandem mass spectrometry, and urine gas chromatography-mass spectrometry were, retrospectively, analyzed.

PATIENT CONCERNS

Patient 1 was a 1.6-year-old female. She was admitted to the hospital with 2-months history of general irritability and disturbance of consciousness for a day. Patient 2 was a 3.7-year-old female. She was admitted to the hospital due to decline of language ability and irritability for 5 days. Blood tandem mass spectrometry and urine gas chromatography-mass spectrometry showed uracil and orotate increased significantly in urine while amino acids in the urea cycle ring were in the normal range. The features of brain MRI are consistent with those of urea circulatory disorders. Gene detection showed 1 novel mutation in the OTC gene (c.658C>T) in patient 1 and, 1 novel mutation (c.298+2T>G) in the OTC gene in patient 2.

DIAGNOSIS

Combined with metabolic screening and gene detection, both patients were diagnosed with OTCD.

INTERVENTIONS

The patients' condition improved after following a low protein diet and receiving treatments for decreasing blood ammonia, energy supplement, correcting acid-base imbalance, and other symptomatic treatments.

OUTCOMES

After prompt symptomatic treatment, the consciousness and cognition of the children improved. Besides, liver function also improved significantly.

CONCLUSIONS

For patients with neurological symptoms and unexplained increase in transaminase and ammonia, OTCD should be considered as a possible diagnosis. Brain MRI can help the diagnosis of genetic metabolic encephalopathy and reflect the level of brain injury. Metabolic screening and genetic detection are helpful to make a confirmed diagnosis.

Liver involvement in urea cycle disorders: a review of the literature

Urea cycle disorders (UCDs) are inborn errors of metabolism of the nitrogen detoxification pathway and encompass six principal enzymatic deficiencies. The aging of UCD patients leads to a better knowledge of the long-term natural history of the condition and to the reporting of previously unnoticed manifestations. Despite historical evidence of liver involvement in UCDs, little attention has been paid to this organ until recently. Hence, we reviewed the available scientific evidence on acute and chronic liver dysfunction and liver carcinogenesis in UCDs and discuss their pathophysiology. Overall, liver involvement, such as acute liver failure or steatotic-like disease, which may evolve toward cirrhosis, has been reported in all six main UCDs. Excessive glycogen storage is also a prominent histologic feature, and hypoglycemia has been reported in citrin deficiency. Hepatocarcinomas seem frequent in some UCDs, such as in citrin deficiency, and can sometimes occur in non-cirrhotic patients. UCDs may differ in liver involvement according to the enzymatic deficiency. Ornithine transcarbamylase deficiency may be associated more with acute liver failure and argininosuccinic aciduria with chronic liver failure and cirrhosis. Direct toxicity of metabolites, downstream metabolic deficiencies, impaired tricarboxylic acid cycle, oxidative stress, mitochondrial dysfunction, energy deficit, and putative toxicity of therapies combine in various ways to cause the different liver diseases reported.

Toxic-metabolic Risk Factors in Pediatric Pancreatitis: Recommendations for Diagnosis, Management, and Future Research

Pancreatitis in children can result from metabolic and toxic risk factors, but the evidence linking these factors is sparse. We review the evidence for association or causality of these risk factors in pancreatitis, discuss management strategies, and their rationale. We conducted a review of the pediatric pancreatitis literature with respect to the following risk factors: hyperlipidemia, hypercalcemia, chronic renal failure, smoking exposure, alcohol, and medications. Areas of additional research were identified. Hypertriglyceridemia of 1000 mg/dL or greater poses an absolute risk for pancreatitis; persistent elevations of calcium are predisposing. Further research is necessary to determine whether end-stage renal disease leads to increased pancreatitis in children similar to adults. It is unknown whether cigarette smoking exposure, which clearly increases risk in adults, also increases risk in children. The role of alcohol in pediatric pancreatitis, whether direct or modifying, needs to be elucidated. The evidence supporting most cases of medication-induced pancreatitis is poor. Drug structure, improper handling of drug by host, and bystander status may be implicated. Other pancreatitis risk factors must be sought in all cases. The quality of evidence supporting causative role of various toxic and metabolic factors in pediatric pancreatitis is variable. Careful phenotyping is essential, including search for other etiologic risk factors. Directed therapy includes correction/removal of any agent identified, and general supportive measures. Further research is necessary to improve our understanding of these pancreatitis risk factors in children.