Phenotypic and genetic spectra of galactose mutarotase deficiency: A nationwide survey conducted in Japan.

PURPOSE: Galactose mutarotase (GALM) deficiency was first reported in 2019 as the fourth type of galactosemia. This study aimed to investigate the clinical and genotypic spectra of GALM deficiency. METHODS: This was a questionnaire-based retrospective survey conducted in Japan between February 2022 and March 2023. RESULTS: We identified 40 patients with GALM deficiency in Japan (estimated prevalence: 1:181,835). Four of 38 patients (10.5%) developed cataracts, which resolved with lactose restriction in 3 out of 4 patients. Transient transaminitis was the most common symptom (23.1%). All of the patients followed lactose restriction; discontinuation of the restriction after infancy did not cause any complications. Moreover, none of the participants experienced long-term complications. Two variants, GALM NM_138801.3: c.294del and c.424G>A, accounted for 72.5% of the identified pathogenic variants. The patients showed moderately elevated blood galactose levels with lactose intake; however, the elevation was lower than that observed in galactokinase deficiency. CONCLUSION: GALM deficiency is characterized by a similar but milder phenotype and lower blood galactose elevation than in galactokinase deficiency. Diagnosis and initiation of lactose restriction in early infancy should be essential for prevention of cataracts, especially in cases of irreversible opacity.

One-year-old boy with refractory Listeria monocytogenes meningitis due to persistent hypercytokinemia.

We had a case of Listeria monocytogenes (LM) meningitis complicated with hypercytokinemia and hemophagocytic lymphohistiocytosis in a healthy 22-month-old boy. He was admitted to our hospital with a fever, vomiting, mild consciousness disturbances, and extraocular muscle paralysis. Magnetic resonance imaging (MRI) revealed bilateral deep white matter lesions. After receiving ampicillin, meropenem, and gentamicin, his cerebrospinal fluid (CSF) culture results turned negative on the third day of hospitalization. However, the fever intermittently persisted, and it took approximately 40 days to completely resolve. During this period, various inflammatory cytokine levels, particularly neopterin, in the blood and CSF remained elevated. Therefore, long-term administration of corticosteroids in addition to antibiotics was required. The use of dexamethasone appeared to be effective for neurological disorders such as consciousness disturbance and extraocular muscle paralysis associated with abnormal brain MRI findings. LM meningitis may present with encephalopathy and persistent fever due to hypercytokinemia. In such cases, corticosteroid therapy should be considered.

The efficacy of pacemaker implantation for extracardiac total cavopulmonary connection in a pediatric patient with bradycardia-tachycardia syndrome.

A 9-year-old boy, diagnosed with double outlet right ventricle after birth, suffered sinus node dysfunction and non-sustained junctional tachycardia after an extracardiac total cavopulmonary connection (TCPC). Spontaneous atrial tachycardia appeared 3 years after an extracardiac TCPC. Sotalol was administered but the bradycardia was obvious. It was difficult to increase sotalol and atrial tachycardia was uncontrollable. Atrial tachycardia continued with symptoms; direct current (DC) cardioversion was frequently required. Five years after extracardiac TCPC, we implanted a pacemaker with atrial antitachycardia pacing (ATP) using epicardial leads. On day 2 post operation, wide QRS tachycardia appeared. Due to decreased blood pressure, DC cardioversion was immediately performed, but it recurred from atrial premature contraction. We judged this was atrial tachycardia with 1:1 atrioventricular conduction based on an intracardiac electrogram and it was terminated by burst atrial pacing from the pacemaker. After changing atrial pacing rate to 150 ppm, atrial tachycardia could be suppressed. Due to atrial pacing and increasing sotalol gradually, junctional tachycardia terminated spontaneously, and atrial tachycardia was not induced after pacemaker implantation. In conclusion, implantation of a pacemaker with ATP and intensification of antiarrhythmic drugs is an effective treatment strategy for pediatric patients with bradycardia-tachycardia syndrome after extracardiac TCPC. .

Severity estimation of very-long-chain acyl-CoA dehydrogenase deficiency via 13C-fatty acid loading test.

BACKGROUND: The clinical severity of very-long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is difficult to predict using conventional diagnostic methods. METHODS: Peripheral blood mononuclear cells obtained from 14 VLCAD deficiency patients and 23 healthy adults were loaded with carbon-13-universally labeled (U-13C-) fatty acids. Differences in acylcarnitine ratios between the patients and healthy groups and correlations between acylcarnitine ratios and a newly established clinical severity score (CSS) in the patient group were statistically examined. RESULTS: There was a significant decrease in the 13C-C2/13C-C18 and 13C-C12/13C-C14 ratios in the U-13C-stearic acid loading test and in the 13C-C2/13C-C18:1 and 13C-C12:1/13C-C14:1 ratios in the U-13C-oleic acid loading test in the patient group. The values of each ratio were significantly correlated with the CSS, suggesting that they could predict disease severity. Additionally, patients with a higher 13C-C16/13C-C18 ratio than the 13C-C14/13C-C18 ratio in the U-13C-stearic acid loading test had a significantly higher CSS and were presumed to have more severe disease. CONCLUSIONS: Our data indicated that this method could be used to predict the clinical severity of VLCAD deficiency, and identify patients at a risk of severe disease. IMPACT: We established a novel method to predict the severity of VLCAD deficiency by performing a loading test with carbon-13-labeled fatty acids on peripheral blood mononuclear cells. The U-13C-oleic acid loading test was useful for comparing the patient group with the control group in terms of disease severity. The U-13C-stearic acid loading test was useful for identifying the more severely affected patients. These methods are relatively less invasive and enable rapid evaluation of the clinical severity.

Two autopsy cases of sudden unexpected death from Dravet syndrome with novel de novo SCN1A variants.

AIM: Dravet syndrome (DS) is characterized by high epilepsy-related premature mortality with a markedly young age at death, however, autopsy report of sudden unexpected death with DS has been fewer than expected. METHODS: We report two autopsy cases with sudden unexpected death from DS. Case 1 was a 13-year-old male who drowned in a bathtub, and Case 2 was a 3-year-old female who died while sleeping. In Case 1, the blood concentration of the anticonvulsant, valproic acid, was below the recommended therapeutic range. Neuropathological investigation and genetic analysis of 402 cardiovascular disease-related and 146 epilepsy-related genes by next generation sequencing were applied. RESULTS: No significant neuronal loss with gliosis was observed in the brain of either patient. Although possible mild malformations of cortical development were found in both, the degree thereof was similar to that of age-matched controls. Genetic analysis identified a novel variant in SCN1A intron 23 (c.4477-3T > C) in Case 1 that falls outside of the minor splicing consensus sequence. In vitro splicing functional assays with minigene constructs revealed that this intronic variant leads to a 2-bp insertion immediately before exon 24 that results in protein truncation. Similarly, a novel de novo missense mutation of unknown significance, SCN1A_Arg187Pro, was identified in Case 2. In both cases, we also identified cardiomyopathy-related variants classified as likely pathogenic; however, the effect of these variants at death was minimal because there was an absence of pathological change indicating inherited cardiomyopathy. CONCLUSION: The present cases emphasize the need for multifaceted examination of DS cases so as to obtain a definitive autopsy diagnosis and to explore the mechanism of sudden unexpected death.

Long QT syndrome with a de novo CALM2 mutation in a 4-year-old boy.

BACKGROUND: Human calmodulin (CALM) gene mutation has been reported to be related to inherited arrhythmia syndromes, but the genotype-phenotype relationship remains unclear. METHODS AND RESULTS: We report here a 4-year-old boy who had cardiac arrest while playing in a kindergarten playground. Cardiopulmonary resuscitation was initiated immediately. Eleven minutes after the cardiac arrest, ambulance crews arrived and an automated external defibrillator was attached. His heart rhythm, which was ventricular fibrillation (VF), was returned to sinus rhythm after only one shock delivery. The boy was brought to hospital by air ambulance. During transfer, electrocardiogram (ECG) showed transient VF. On arrival, chest radiograph showed a cardiothoracic ratio of 55% without pulmonary congestion. A 12-lead ECG showed a normal sinus rhythm, biphasic T wave, and prolongation of the corrected QT interval. On ECG, VF was preceded by torsade de pointes or frequent polymorphic premature ventricular contractions (PVC). Echocardiography showed a normal heart structure with decreased cardiac function. On the second day of hospitalization, ECG showed remarkable QT prolongation, T-wave alternans, and frequent PVC. Thereafter, propranolol was started. The ECG showed rapid improvement of QT prolongation and T-wave abnormality. Genetic test indicated a CALM2 mutation, and he was diagnosed with long QT syndrome-15 (LQT15). CONCLUSIONS: CALM mutations cause long QT syndrome (LQTS), catecholaminergic polymorphic ventricular tachycardia (CPVT) and idiopathic VF. This patient with a CALM2 p.N98S mutation had both phenotypes of LQTS and CPVT.

Exclusive breast-feeding and postnatal changes in blood sodium, ketone, and glucose levels.

BACKGROUND: Blood sodium and ketone are parameters of dehydration and fasting, respectively. Little is known, however, about the postnatal changes in these parameters in healthy, term, exclusively breast-fed neonates. METHODS: Capillary blood sodium, ß-hydroxybutyrate (ß-OHB), and glucose levels in 628 samples obtained from 392 healthy, term, exclusively breast-fed neonates during the first 12-143 h of life were examined. RESULTS: Blood sodium and ß-OHB gradually increased and reached a peak at 48-59 h of life (mean blood sodium, 142.3 ± 2.8 mEq/L; mean blood sodium increase, 3.3 mEq/L; mean ß-OHB, 1.16 ± 0.46 mmol/L; mean ß-OHB increase, 0.65 mmol/L), and then gradually decreased and reached a nadir at 120-143 h of life. Blood glucose gradually decreased and reached a nadir at 48-59 h of life (mean, 62.4 ± 12.2 mg/dL; mean decrease, 4.7 mg/dL), and then gradually increased and peaked at 120-143 h of life. These changes were synchronized with changes in weight-loss percentage. CONCLUSIONS: The postnatal changes in blood sodium, ketone, and glucose levels during the first 12-143 h of life are described in healthy, term, exclusively breast-fed neonates. The parameters seemed to be associated with the sufficiency of the breast-milk supply. These results can serve as normal reference values for healthy, term, exclusively breast-fed neonates during the early postnatal period.

Catecholaminergic polymorphic ventricular tachycardia managed as orthostatic dysregulation and epilepsy in 11- and 15-year-old sisters.

BACKGROUND: In pediatric patients, syncope commonly occurs as vasovagal syncope, or in epilepsy or orthostatic dysregulation. Cardiogenic syncope is rare but it is lethal, and needs to be promptly diagnosed and treated. METHODS AND RESULTS: We describe the cases of 11- and 15-year-old sisters with frequent syncope during exercise and emotional stress since the age of 10 and 12, respectively. There were no abnormalities on 12-lead electrocardiogram (ECG) at rest. They were first diagnosed with orthostatic dysregulation and epilepsy. Because of recurrent exercise-induced syncope, cardiac examinations were performed. On treadmill exercise stress test, bidirectional ventricular tachycardia was induced in the 11-year-old girl, which degenerated into ventricular fibrillation; frequent polymorphic premature ventricular contractions were induced in her elder sister. They were diagnosed with catecholaminergic polymorphic ventricular tachycardia (CPVT) and started on oral beta-blockers and exercise restriction. CONCLUSIONS: It is important to suspect CPVT in pediatric exercise-induced syncope, and to recognize that CPVT does not show ECG abnormalities at rest.

Infantile traumatic brain injury with a biphasic clinical course and late reduced diffusion.

Reduced diffusion in the subcortical white matter has been reported in some infants with traumatic brain injury (TBI), including abusive head trauma. However, the pathomechanisms of the lesions and clinical features are uncertain. We herein report two infants with TBI who presented with biphasic clinical courses and late reduced diffusion in the subcortical white matter, and reviewed seven clinically and radiologically similar patients with TBI. Their clinical features (secondary neurological symptoms on days 3 to 6) and radiological findings (normal diffusion on days 1 to 2, followed by reduced diffusion on days 3 to 6) are very similar to those observed in patients with acute encephalopathy with biphasic seizures and late reduced diffusion (AESD). MR spectroscopy in one patient revealed a transient increase of glutamine, which is also observed in AESD, suggesting excitotoxicity as a possible pathomechanism.

Capillary Blood Ketone Levels as an Indicator of Inadequate Breast Milk Intake in the Early Neonatal Period.

OBJECTIVE: To determine the utility of capillary blood ketone levels as an indicator of inadequate intake of breast milk in the early postnatal period. STUDY DESIGN: Levels of capillary blood beta-hydroxybutyrate (ßOHB), the main ketone body in the blood, were measured with a bedside ketone meter in 585 full-term neonates aged 48-95 hours who were breastfed exclusively. Relationships between weight-loss percentage, blood sodium, glucose, pH, partial pressure of carbon dioxide, base-deficit levels, and ßOHB levels were investigated. The diagnostic accuracy of ßOHB for predicting excessive weight loss (weight loss ≥10% of birth weight) and hypernatremic dehydration (blood sodium level ≥150 mEq/L) was determined. RESULTS: ßOHB levels were correlated positively with weight-loss percentage and blood sodium levels and were correlated negatively with blood glucose levels. The diagnostic accuracy of ßOHB was 0.846 (optimal cut off, 1.55 mmol/L; sensitivity, 80.9%, specificity, 74.0%) for predicting excessive weight loss and 0.868 (optimal cut off, 1.85 mmol/L; sensitivity, 94.3%; specificity, 69.9%) for predicting hypernatremic dehydration according to the area under the receiver operating characteristic curve. Multiple logistic analysis revealed that ßOHB and weight loss percentage were the only independent predictors of hypernatremic dehydration. Increases in ßOHB levels also were associated with worsening metabolic acidosis and hypocapnia. CONCLUSION: High ßOHB levels were associated with inadequate intake of breast milk in the early postnatal period. The use of bedside capillary blood ketone levels may be clinically useful as an indicator of dehydration, energy depletion, and acid-base imbalance in breastfeeding infants in the early postnatal period.

Longitudinal study on the effectiveness of vitamin D supplements in exclusively breast-fed infants.

Vitamin D deficiency is a common health problem in infancy. Breast-fed infants are at a higher risk of rickets than formula-fed infants. We observed fluctuations in vitamin D levels in infancy (phase I, 2009-2010) and considered the benefits of vitamin D supplementation specifically in exclusively breast-fed infants in Japan (phase II, 2015). Infants born at our hospital were enrolled in this study. In phase I, we measured 25-hydroxyvitamin D [25(OH)D] levels at 1- to 6-mo intervals from birth. In phase II, we measured 25(OH)D levels before and after supplementation. Vitamin D deficiency was defined as 25(OH)D levels of < 20 ng/mL. All 38 infants in phase I were deficient at birth, and none of the exclusively breast-fed infants achieved 25(OH)D sufficiency by 5 mo of age. Formula-fed infants achieved 25(OH)D sufficiency earlier. The majority of the 71 infants in phase II were deficient at birth. We recommended an oral vitamin D supplement at a daily dose of 4.0 µg for the 15 exclusively breast-fed infants, starting at 1 mo of age; 14 (93.3%) of them achieved 25(OH)D sufficiency by 5 months of age. Exclusively breast-fed infants are at a high risk of vitamin D deficiency; adequate supplementation is an effective preventative strategy.

Virus myocarditis in a 1-month-old boy presenting as two types of paroxysmal supraventricular tachycardia.

Herein we describe the case of a 1-month-old boy with acute viral myocarditis, who presented with two kinds of paroxysmal supraventricular tachycardia, and who was cured after medical treatment. He was brought to the emergency room with poor feeding due to fever. On the third day of hospitalization, a narrow QRS tachycardia (180-200 beats/min) was detected. Echocardiography showed a high echoic area at the atrial septum around the atrioventricular node. The patient was clinically diagnosed with acute myocarditis. The narrow QRS tachycardia was diagnosed as incessant junctional ectopic tachycardia. The patient was treated with propranolol and landiolol. The frequency of the tachycardia decreased, but a different narrow QRS tachycardia was detected on the 15th day of hospitalization on electrocardiogram (220 beats/min), which was ascribed to atrioventricular nodal re-entrant tachycardia. Atenolol was effective for the tachycardia. At 2 years follow up, cardiac function was normal and tachycardia had not recurred.

Serum tau protein as a marker of disease activity in enterohemorrhagic Escherichia coli O111-induced hemolytic uremic syndrome.

Tau protein levels in cerebrospinal fluid (CSF) and serum are elevated in patients with various central nervous system diseases. We investigated whether serum tau protein levels are useful for predicting and assessing disease activity of acute encephalopathy (AE) in enterohemorrhagic Escherichia coli (EHEC) O111-induced hemolytic uremic syndrome (HUS; EHEC encephalopathy). Serum samples were obtained from 14 patients with EHEC O111/HUS, 20 patients with non-EHEC-related AE, and 20 age- and sex-matched healthy controls. CSF samples were obtained from 2 patients with EHEC encephalopathy and 20 patients with non-EHEC-related AE. Tau protein levels and levels of several proinflammatory cytokines were quantified by enzyme-linked immunosorbent assays. Results were compared with the clinical features of EHEC encephalopathy, including magnetic resonance image (MRI) findings. Serum tau levels in patients with EHEC encephalopathy were significantly elevated compared with those in patients with EHEC O111/HUS without encephalopathy, patients with non-EHEC-related AE, and healthy controls. The ratio of CSF tau levels to serum tau levels was >1.0 in all patients with non-EHEC-related AE but <1.0 in 2 patients with EHEC encephalopathy. Serum tau protein levels increased rapidly and markedly in patients with severe EHEC 0111/HUS and encephalopathy when HUS occurred, but were not elevated in mild patients, even in the HUS phase. Furthermore, changes in serum tau protein levels in patients with EHEC encephalopathy were consistent with abnormalities on brain MRI and were positively correlated with proinflammatory cytokine levels. Our results indicate that serum tau protein might be useful to predict and assess disease activity of EHEC encephalopathy.

Extensive serum biomarker analysis in patients with enterohemorrhagic Escherichia coli O111-induced hemolytic-uremic syndrome.

Proinflammatory cytokines are related to the pathogenesis of enterohemorrhagic Escherichia coli infection and hemolytic-uremic syndrome (HUS). We employed an antibody array that simultaneously detects 174 serum cytokines. We identified five serum biomarkers, namely insulin growth factor-binding protein-2, angiopoietin-2, soluble interleukin-6 receptor, soluble tumor necrosis factor receptor type II, and matrix metalloprotease protein-3 whose levels increased with the development of HUS. Furthermore, the levels of these cytokines were significantly increased in severe HUS compared with mild HUS. These cytokines might play an important role in the pathogenesis of HUS and may also be used to predict the severity of HUS.

Cytokine profiles of patients with enterohemorrhagic Escherichia coli O111-induced hemolytic-uremic syndrome.

Proinflammatory cytokines are related to the pathogenesis of enterohemorrhagic Escherichia coli (EHEC) infection and hemolytic-uremic syndrome (HUS). We assessed the kinetics of the release of cytokines such as neopterin, interleukin (IL)-6, IL-8 and tumour necrosis factor (TNF)-α and the soluble forms of type I and II TNF receptors during EHEC O111-induced HUS (EHEC O111/HUS). Fourteen patients with EHEC O111/HUS were enrolled in this study. Serum concentrations of all cytokines other than TNF-α were significantly elevated in patients with severe HUS compared with those in patients with mild HUS. Although serum concentrations of TNF-α were not significantly higher in patients with severe HUS, most patients with acute encephalopathy showed elevated TNF-α levels. Serum concentrations of these cytokines rapidly and markedly increased, and massive hypercytokinaemia developed 1 day before the diagnosis of HUS in patients with severe HUS. Changes in the number of white blood cells and concentration of serum lactate dehydrogenase were significantly larger between the onset of hemorrhagic colitis and the time of the diagnosis of HUS in patients with severe HUS compared with those in patients with mild HUS. Proinflammatory cytokines play an important role in the pathogenesis of EHEC infection and development of severe complications, including HUS and encephalopathy. Monitoring the cytokine profile may be useful for assessing disease activity of EHEC O111 infections.

Thyroglobulin gene mutation with cold nodule on thyroid scintigraphy.

Thyroglobulin gene mutation is a rare cause of congenital hypothyroidism, but thyroglobulin gene mutations are thought to be associated with thyroid cancer development. A 21-year-old Japanese man treated with levothyroxine for congenital hypothyroidism had an enlarged thyroid gland with undetectable serum thyroglobulin despite elevated serum TSH level. The patient was diagnosed with thyroglobulin gene mutation, with compound heterozygosity for Gly304Cys missense mutation and Arg432X nonsense mutation. Ultrasonography showed a hypovascular large tumor in the left lobe that appeared as a cold nodule on thyroid scintigraphy. He underwent total thyroidectomy, but pathological study did not reveal findings of thyroid carcinoma, but rather a hyperplastic nodule with hemorrhage. Strong cytoplasmic thyroglobulin immunostaining was observed, but sodium iodide symporter immunostaining was hardly detected in the hyperplastic nodule. The clinical characteristics of patients with thyroglobulin gene mutations are diverse, and some patients are diagnosed by chance on examination of goiter in adults. The presence of thyroid tumors that appear as cold nodules on thyroid scintigraphy should consider the potential for thyroid carcinoma, if the patient has relatively low serum thyroglobulin concentration in relation to the degree of TSH without thyroglobulin autoantibody.

Left atrium thrombus in an extremely low-birthweight infant with late-onset circulatory dysfunction.

A left atrium thrombus, potentially a life-threatening complication, is an extremely rare in early infancy. Most cases are caused by mal-placement of central venous catheters or related to congenital heart diseases with left atrial blood congestion. Here we present an extremely low birth weight infant who developed a left atrial thrombus during the course of late onset circulatory dysfunction. The thrombus was successfully treated by recombinant tissue plasminogen activator. A hemodynamically unstable condition like late onset circulatory dysfunction should be taken into consideration as a potential risk condition of this rare disease.