Carglumic Acid Contributes to a Favorable Clinical Course in a Case of Severe Propionic Acidemia

Propionic acidemia (PA) is manifested as an abnormal accumulation of propionic acid and its metabolites, including methylcitrate, 3-hydroxypropionic acid, and propionylglycine, and is caused by a defect of propionyl-CoA carboxylase. PA is complicated by acute life-threatening metabolic crises, which are precipitated by a catabolic state and result in multiple organ failure or even death, if untreated. A neonate with PA recovered from the first metabolic crisis 3 days after birth but developed a second metabolic crisis during the recovery phase. This patient was considered to have severe PA and was accordingly given carglumic acid treatment in combination with carnitine supplementation and protein restriction, which was expected to prevent a recurrent metabolic attack. The patient did not develop hyperammonemia after receiving carglumic acid and was never hospitalized. Moreover, she did not present with acidosis even during viral infection. At 26 months of age, she led a stable life while receiving carglumic acid and regular rehabilitation. Carglumic acid treatment in combination with carnitine supplementation and protein restriction prevented metabolic decompensation, which would have otherwise required hospitalization, and resulted in improved quality of life and developmental outcomes

Adrenocorticotropic Hormone Therapy Improved Spasms and Sleep Disturbance in Smith–Magenis Syndrome: A Case Report

Smith–Magenis syndrome (SMS) is a complex disorder characterized by variable mental retardation, sleep disturbances, craniofacial and skeletal anomalies, self-injurious and attention-seeking behaviors, and speech and motor delays. The case of a 14-month-old girl with SMS who was experiencing spasm clusters and sleep disturbances with sleep–wake intervals of 1.5 to 2 h persisting from the neonatal period was examined. The patient’s spasms stopped and interictal electroencephalography did not show epileptic discharges after undergoing a high-dose adrenocorticotropic hormone (ACTH) therapy. Moreover, the patient’s sleep cycle stabilized 1 month after receiving the ACTH therapy. Dramatic reductions in the patient’s self-injurious behaviors were also noted. At 1 year following ACTH treatment, the patient’s improved sleep was maintained. High-dose ACTH treatment was considered to contribute to the normal adaptation of the hypothalamic–pituitary–adrenal axis by regulating the release of corticotropin-releasing hormone, resulting in improvement of the patient’s infantile spasms and sleep disturbances

Urea cycle disorders-update

The urea cycle is a metabolic pathway for the disposal of excess nitrogen, which arises primarily as ammonia. Nitrogen is essential for growth and life-maintenance, but excessive ammonia leads to life-threatening conditions. The urea cycle disorders (UCDs) comprise diseases presenting with hyperammonemia that arise in either the neonatal period (about 50% of cases) or later. Congenital defects of the enzymes or transporters of the urea cycle cause the disease. This cycle utilizes five enzymes, two of which, carbamoylphosphate synthetase 1 and ornithine transcarbamylase are present in the mitochondrial matrix, whereas the others (argininosuccinate synthetase, argininosuccinate lyase and arginase 1) are present in the cytoplasm. In addition, N-acetylglutamate synthase and at least two transporter proteins are essential to urea cycle function. Severity and age of onset depend on residual enzyme or transporter function and are related to the respective gene mutations. The strategy for therapy is to prevent the irreversible toxicity of high-ammonia exposure to the brain. The pathogenesis and natural course are poorly understood because of the rarity of the disease, so an international registry system and novel clinical trials are much needed. We review here the current concepts of the pathogenesis, diagnostics, including genetics and treatment of UCDs

Total spondylectomy following carbon ion radiotherapy to treat chordoma of the mobile spine.

The main form of treatment of a chordoma of the mobile spine is total en bloc spondylectomy (TES), but the clinical results are not satisfactory. Stand-alone carbon ion radiotherapy (CIRT) for bone and soft-tissue sarcomas has recently been reported to have a high rate of local control with a low rate of local recurrence. We report two patients who underwent TES after CIRT for treating a chordoma in the lumbar spine with good medium-term outcomes. At operation, there remained histological evidence of viable tumour cells in both cases. After the combination use of TES following CIRT, neither patient showed signs of recurrence at the follow-up examination. These two cases suggest that CIRT should be combined with total spondylectomy in the treatment of chordoma of the mobile spine. Cite this articl

Early-onset neonatal hyperkalemia associated with maternal hypermagnesemia: a case report

Abstract Background Neonatal nonoliguric hyperkalemia (NOHK) is a metabolic abnormality that occurs in extremely premature neonates at approximately 24 h after birth and is mainly due to the immature functioning of the sodium (Na+)/potassium (K+) pump. Magnesium sulfate is frequently used in obstetrical practice to prevent preterm labor and to treat preeclampsia; this medication can also cause hypermagnesemia and hyperkalemia by a mechanism that is different from that of NOHK. Herein, we report the first case of very early-onset neonatal hyperkalemia induced by maternal hypermagnesemia. Case presentation A neonate born at 32 weeks of gestation developed hyperkalemia (K+ 6.4 mmol/L) 2 h after birth. The neonate’s blood potassium concentration reached 7.0 mmol/L 4 h after birth, despite good urine output. The neonate and his mother had severe hypermagnesemia caused by intravenous infusion of magnesium sulfate given for tocolysis due to pre-term labor. Conclusion The early-onset hyperkalemia may have been caused by the accumulation of potassium ions transported through the placenta, the shift of potassium ions from the intracellular to the extracellular space in the infant due to the malfunctioning of the Na+/K+ pump and the inhibition of renal distal tube potassium ion secretion, there is a possibility that these mechanisms were induced by maternal and fetal hypermagnesemia after maternal magnesium sulfate administration. Because neonatal hyperkalemia poses a significant risk for the development of life-threatening cardiac arrhythmia, this case highlights the necessity of maternal blood magnesium monitoring during magnesium sulfate administration and neonatal blood potassium monitoring when there is severe maternal hypermagnesemia at delivery

Detection of novel Fabry disease‐associated pathogenic variants in Japanese patients by newborn and high‐risk screening

Abstract Background In Japan, newborn and high‐risk screening for Fabry disease (FD), an inherited X‐linked disorder caused by GLA mutations, using dried blood spots was initiated in 2006. In newborn screening, 599,711 newborns were screened by December 2018, and 57 newborns from 54 families with 26 FD‐associated variants were detected. In high‐risk screening, 18,235 individuals who had symptoms and/or a family history of FD were screened by March 2019, and 236 individuals from 143 families with 101 FD‐associated variants were detected. Totally 3, 116 variants were detected; 41 of these were not registered in Fabry‐database.org or ClinVar and 33 were definitely novel. Herein, we report the clinical outcomes and discuss the pathogenicity of the 41 variants. Methods We traced nine newborns and 46 individuals with the 33 novel variants, and nine newborns and 10 individuals with eight other variants not registered in the FD database, and analyzed the information on symptoms, treatments, and outcomes. Results Thirty‐eight of the 46 individuals with the 33 novel variants showed symptoms and received enzyme‐replacement therapy and/or chaperone treatment. Conclusion Delayed diagnosis should be avoided in patients with FD. Our results will help clinicians diagnose FD and determine the appropriate treatment for patients with these variants

Expression and function of the urea cycle in widely-used hepatic cellular models

The group of rare metabolic defects termed urea cycle disorders (UCDs) occur within the ammonia elimination pathway and lead to significant neurocognitive sequelae for patients surviving decompensation episodes. Besides orthotopic liver transplantation, curative options are lacking for UCDs, with dietary management being the gold clinical standard. Novel therapeutic approaches are essential for UCDs; however, such effort presupposes preclinical testing in cellular models that effectively capture disease manifestation. Several cellular and animal models exist and aim to recapitulate the broad phenotypic spectrum of UCDs; however, the majority of those lack extensive molecular and biochemical characterization. The development of cellular models is emerging since animal models are extremely time and cost consuming, and subject to ethical considerations, including the 3R principle that endorses animal welfare over unchecked preclinical testing. The aim of this study was to compare the extent of expression and functionality of the urea cycle in two commercial hepatoma-derived cell lines, induced pluripotent stem cell hepatocytes (iPSC-Heps), primary human hepatocytes (PHHs) and human liver cell preparations. Using immunoblotting, immunocytochemistry, and stable isotope tracing of the urea cycle metabolites, we identified that the hepatoma-derived, 2-week differentiated HepaRG cells are urea cycle proficient and behave as cellular alternatives to PHHs. Furthermore, HepaRG cells were superior to iPSC-Heps, which are known to exhibit batch-to-batch variabilities in terms of hepatic maturity and enzyme expression. Finally, HepG2 cells lack the urea cycle enzymes ornithine transcarbamylase and arginase 1, the transporter ORNT1, which limits their suitability as model for the study of UCDs