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ObjectiveNeonatal-onset mitochondrial disease has not been fully characterised owing to its heterogeneity. We analysed neonatal-onset mitochondrial disease in Japan to clarify its clinical features, molecular diagnosis and prognosis.DesignRetrospective observational study from January 2004 to March 2020.SettingPopulation based.PatientsPatients (281) with neonatal-onset mitochondrial disease diagnosed by biochemical and genetic approaches.InterventionsNone.Main outcome measuresDisease types, initial symptoms, biochemical findings, molecular diagnosis and prognosis.ResultsOf the 281 patients, multisystem mitochondrial disease was found in 194, Leigh syndrome in 26, cardiomyopathy in 38 and hepatopathy in 23 patients. Of the 321 initial symptoms, 236 occurred within 2 days of birth. Using biochemical approaches, 182 patients were diagnosed by mitochondrial respiratory chain enzyme activity rate and 89 by oxygen consumption rate. The remaining 10 patients were diagnosed using a genetic approach. Genetic analysis revealed 69 patients had nuclear DNA variants in 36 genes, 11 of 15 patients had mitochondrial DNA variants in five genes and four patients had single large deletion. The Cox proportional hazards regression analysis showed the effects of Leigh syndrome (HR=0.15, 95% CI 0.04 to 0.63, p=0.010) and molecular diagnosis (HR=1.87, 95% CI 1.18 to 2.96, p=0.008) on survival.ConclusionsNeonatal-onset mitochondrial disease has a heterogenous aetiology. The number of diagnoses can be increased, and clarity regarding prognosis can be achieved by comprehensive biochemical and molecular analyses using appropriate tissue samples.

BACKGROUND Cardiomyopathy is a risk factor for poor prognosis in pediatric patients with mitochondrial disease. However, other risk factors including genetic factors related to poor prognosis in mitochondrial disease has yet to be fully elucidated. METHODS AND RESULTS Between January 2004 and September 2019, we enrolled 223 consecutive pediatric mitochondrial disease patients aged

AimsMitochondrial cardiomyopathy (MCM) is difficult to make a definite diagnosis because of various cardiovascular phenotypes and no diagnostic criteria in the pathology examination. We aim to add myocardial pathology to the diagnostic criteria for mitochondrial respiratory chain disorders.MethodsQuantitative analysis of mitochondria using electron microscopy and immunohistopathological analysis with respiratory chain enzyme antibodies were performed in 11 patients with hypertrophic or restrictive cardiomyopathy who underwent endomyocardial biopsy for possible MCM . Respiratory chain enzymatic assay in biopsied myocardium and genetic studies were also performed in all the subjects to define MCM.ResultsFour patients were diagnosed with MCM according to the recent criteria of mitochondrial respiratory chain disorders. Using electron microscopy with quantitative analysis, the volume density of mitochondria within cardiac muscle cells was significantly increased in the MCM group compared with the non-MCM group (p=0.007). Immunohistopathological results were compatible with the result of the respiratory chain enzymatic assay.ConclusionsPathological diagnosis of MCM could be confirmed by a quantitative study of electron microscopy and immunohistopathological analysis using the mitochondrial respiratory chain enzyme subunit antibody.

Leigh syndrome is a major phenotype of mitochondrial diseases in children. With new therapeutic options being proposed, assessing the mortality and clinical condition of Leigh syndrome patients is crucial for evaluating therapeutics. As data are scarce in Japan, we analysed the mortality rate and clinical condition of Japanese Leigh syndrome patients that we diagnosed since 2007. Data from 166 Japanese patients diagnosed with Leigh syndrome from 2007 to 2017 were reviewed. Patients' present status, method of ventilation and feeding, and degree of disability as of April 2018 was analysed. Overall, 124 (74.7%) were living, 40 (24.1%) were deceased, and 2 (1.2%) were lost to follow‐up. Median age of living patients was 8 years (1‐39 years). Median length of disease course was 91 months for living patients and 23.5 months for deceased patients. Nearly 90% of deaths occurred by age 6. Mortality rate of patients with onset before 6 months of age was significantly higher than that of onset after 6 months. All patients with neonatal onset were either deceased or bedridden. MT‐ATP6 deficiency caused by m.8993T>G mutation and MT‐ND5 deficiency induced a severe form of Leigh syndrome. Patients with NDUFAF6, ECHS1, and SURF1 deficiency had relatively mild symptoms and better survival. The impact of onset age on prognosis varied across the genetic diagnoses. The clinical condition of many patients was poor; however, few did not require mechanical ventilation or tube‐feeding and were not physically dependent. Early disease onset and genetic diagnosis may have prognostic value.

Background The mitochondrial DNA MT-ATP6 gene encodes the ATP6 subunit of the mitochondrial ATP synthase. The m.9185 T > C variant in MT-ATP6 has been reported to cause various neurological disorders including late-onset Leigh syndrome (LS). To our knowledge, there has been no reported case of infantile-onset LS associated with the m.9185 T > C variant. Herein, we report a patient with early-onset LS complicated with infantile spasms who exhibited profound developmental delay. Case report A 3-month-old Japanese girl presented with focal seizures. Brain magnetic resonance imaging (MRI) revealed bilateral lesions in the basal ganglia and cerebral peduncle. Laboratory evaluation demonstrated marked elevations of lactate and pyruvate in both venous blood and cerebrospinal fluid. At 6 months, she developed infantile spasms, which were ceased by adrenocorticotropic hormone therapy. At 2 years of age, she was bedridden due to hypotonic quadriplegia and was unable to make eye contact. Whole-exome sequencing identified apparently de novo homoplasmic m.9185 T > C variant in her blood. Conclusion This is the first case report describing early infantile-onset LS associated with the m.9185 T > C variant, and thereby broadens the phenotypic spectrum of m.9185 T > C-related disorders.

Prenatal diagnoses of mitochondrial diseases caused by defects in nuclear DNA (nDNA) or mitochondrial DNA have been reported in several countries except for Japan. The present study aimed to clarify the status of prenatal genetic diagnosis of mitochondrial diseases caused by nDNA defects in Japan. A comprehensive genomic analysis was performed to diagnose more than 400 patients, of which, 13 families (16 cases) had requested prenatal diagnoses. Eight cases diagnosed with wild type homozygous or heterozygous variants same as either of the heterozygous parents continued the pregnancy and delivered healthy babies. Another eight cases were diagnosed with homozygous, compound heterozygous, or hemizygous variants same as the proband. Of these, seven families chose to terminate the pregnancy, while one decided to continue the pregnancy. Neonatal- or infantile-onset mitochondrial diseases show severe phenotypes and lead to lethality. Therefore, such diseases could be candidates for prenatal diagnosis with careful genetic counseling, and prenatal testing could be a viable option for families.

Mitochondrial acyl-CoA dehydrogenase 9 (ACAD9) deficiency is one of the common causes of respiratory chain complex I deficiency, which is characterized by cardiomyopathy, lactic acidemia, and muscle weakness. Infantile cardiomyopathy is the most common phenotype and is usually lethal by the age of 5 years. Riboflavin treatment is known to be effective in ~65% of the patients; however, the remaining are unresponsive to riboflavin and are in need of additional treatment measures. In this report, we describe a patient with ACAD9 deficiency who developed progressive cardiomyopathy at 8 months of age. As the patient’s left ventricular ejection fraction (LVEF) kept decreasing to 45.4% at 1 year 8 months, sodium pyruvate treatment was introduced together with a beta-blocker and coenzyme Q10. This resulted in a steady improvement, with full and sustained normalization of cardiac function without riboflavin. The therapy, therefore, might be a useful addition for the treatment of ACAD9 deficiency.

Cardiomyopathy is a reported indicator of poor prognosis in children with mitochondrial disease. However, the association between prognosis and the genetic background of cardiomyopathy in children with mitochondrial disease has yet to be fully elucidated.Of 137 children with mitochondrial disease whose genetic diagnosis was made between 2004 and 2018, 29 had mitochondrial cardiomyopathy (21%). After a median follow-up of 35 months, the overall survival rate was significantly lower in patients with cardiomyopathy than in those without (p 0.001). Ten-year Kaplan-Meier estimates of overall survival were 18 and 67%, respectively. Among the 21 cardiomyopathy patients who died, two died within one month of birth (COQ4 in one patient, and COX10 in one patient), ten died within one year (BOLA3 in three patients, QRSL1 in two patients, large chromosomal deletions in two patients, MT-ATP6/8 in one patient, MT-TL1 in one patient, and TAZ gene in one patient), and nine died after one year (MT-ND5 in three patients, MT-TL1 in three patients, ACAD9 in one patient, KARS in one patient, and MT-TV in one patient). In the three patients with mitochondrial DNA mutations whose cardiac tissues were available, high heteroplasmy rates in the cardiac tissue were observed for m.8528TC (90%, died at 2 months of age) and m.3243AG (90 and 80%, died at 12 and 13 years of age, respectively).In children with mitochondrial disease, cardiomyopathy was common (21%) and was associated with increased mortality. Genetic analysis coupled with detailed phenotyping could be useful for prognosis.

Key Clinical Message We identified novel compound heterozygous TMEM70 variants in a Japanese patient who had hyperlactacidemia, metabolic acidosis, hyperalaninemia, developmental delay, undescended testicle, and left ventricular noncompaction. The urinary organic acids profile revealed elevated levels of 3‐MGA, and BN‐PAGE/Western blotting analysis and ETC. activity confirmed complex V deficiency.

BackgroundThe spectrum of mitochondrial disease is genetically and phenotypically diverse, resulting from pathogenic variants in over 400 genes, with aerobic energy metabolism defects as a common denominator. Such heterogeneity poses a significant challenge in making an accurate diagnosis, critical for precision medicine.MethodsIn an international collaboration initiated by the European Network for Mitochondrial Diseases (GENOMIT) we recruited 2,023 pediatric patients at 11 specialist referral centers between October 2010 and January 2021, accumulating exome sequencing and HPO-encoded phenotype data. An exome-wide search for variants in known and potential novel disease genes, complemented by functional studies, followed ACMG guidelines.Results1,109 cases (55%) received a molecular diagnosis, of which one fifth have potential disease-modifying treatments (236/1,109, 21%). Functional studies enabled diagnostic uplift from 36% to 55% and discovery of 62 novel disease genes. Pathogenic variants were identified within genes encoding mitochondrial proteins or RNAs in 801 cases (72%), while, given extensive phenotype overlap, the remainder involved proteins targeted to other cellular compartments. To delineate genotype-phenotype associations, our data was complemented with registry and literature data to develop “GENOMITexplorer”, an open access resource detailing patient- (n=3,940), gene- (n=427), and variant-level (n=1,492) associations (prokischlab.github.io/GENOMITexplorer/).ConclusionsReaching a molecular diagnosis was essential for implementation of precision medicine and clinical trial eligibility, underlining the need for genome-wide screening given inability to accurately define mitochondrial diseases clinically. Key to diagnostic success were functional studies, encouraging early acquisition of patient- derived tissues and routine integration of high-throughput functional data to improve patient care by uplifting diagnostic rate.

The identification of the m.4412G > A MT-TM (mt-tRNAMet) mutation was first reported in 2019. The affected individual presented with childhood-onset seizures and myopathy and bilateral basal ganglia changes, with heteroplasmy levels in muscle as high as 90%. Here, we describe another adult-onset patient with the same mutation and additional phenotypes, including hearing impairment, cerebellar ataxia, progressive dementia, and myopathy. The 10% heteroplasmy level observed in skin fibroblasts from this patient are lower than those in the previously reported patient. Our report suggests possible clinical heterogeneity in patients with mitochondrial tRNA mutations based on heteroplasmy levels.

Prenatal diagnoses of mitochondrial diseases caused by defects in nuclear DNA (nDNA) or mitochondrial DNA have been reported in several countries except for Japan. The present study aimed to clarify the status of prenatal genetic diagnosis of mitochondrial diseases caused by nDNA defects in Japan. A comprehensive genomic analysis was performed to diagnose more than 400 patients, of which, 13 families (16 cases) had requested prenatal diagnoses. Eight cases diagnosed with wild type homozygous or heterozygous variants same as either of the heterozygous parents continued the pregnancy and delivered healthy babies. Another eight cases were diagnosed with homozygous, compound heterozygous, or hemizygous variants same as the proband. Of these, seven families chose to terminate the pregnancy, while one decided to continue the pregnancy. Neonatal- or infantile-onset mitochondrial diseases show severe phenotypes and lead to lethality. Therefore, such diseases could be candidates for prenatal diagnosis with careful genetic counseling, and prenatal testing could be a viable option for families.

Hypertension is a rare complication of Leigh Syndrome (LS), but prognosis of patients with hypertension is poor and its presence is indicative of the terminal stage of the disease. Herein, we report a four-year-old girl case diagnosed with LS at 15 months of age who subsequently developed severe hypertension and respiratory failure. Physical examination and laboratory findings did not indicate a secondary cause of hypertension. Her respiratory failure was treated with non-invasive ventilation and hypertension controlled with enalapril, furosemide and spironolactone. To our knowledge, this is the first case of a patient with LS recovering from severe hypertension.

Mitochondrial cardiomyopathy (MCM) is usually recognized as one of the phenotypes of systemic mitochondrial disease. However if there are no cardiac symptoms, it is difficult to make a definite diagnosis because of various cardiovascular phenotypes and no diagnostic criteria in pathological examination. To add myocardial pathology to the diagnostic criteria for mitochondrial respiratory chain disorders, which is the gold standard in the diagnosis of mitochondrial diseases, we performed quantitative analysis of mitochondria using electron microscopy and immunohistopathologic analysis with respiratory chain enzyme antibodies. Ten patients with hypertrophic or restrictive cardiomyopathy who had undergone endomyocardial biopsy were studied. Respiratory chain enzymatic assay and genetic study were performed and four patients were diagnosed with MCM. Using electron microscopy with quantitative analysis, volume density of mitochondria within cardiac muscle cells was significantly increased in the MCM group compared to the non-MCM group (p=0.013). Immunohistopathologic results were compatible with the result of the respiratory chain enzymatic assay. These advanced pathological tests can distinguish MCM from other cardiomyopathies. Results of immunopathologic study Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): The Practical Research Project for Rare/Intractable Diseases from the Japan Agency for Medical Research and Development, AMED.

Leigh syndrome (LS) is most frequently characterized by the presence of focal, bilateral, and symmetric brain lesions Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) is a rare condition, characterized by progressive pyramidal, cerebellar, and dorsal column dysfunction. We describe a case with infantile-onset neurodegeneration, psychomotor retardation, irritability, hypotonia, and nystagmus. Brain MRI demonstrated signal abnormalities in the deep cerebral white matter, corticospinal and dorsal column tracts, and pyramids, which resemble the MRI pattern of a severe form of LBSL, and involvement of basal ganglia and thalamus that resemble the radiological features of LS. We identified biallelic loss-of-function mutations, one novel (c.756delC, p.Thr253Glnfs*44) and another reported (c.1156C &gt, T, p.Arg386Cys), in NDUFV1 (NADH:Ubiquinone Oxidoreductase Core Subunit V1) by exome sequencing. Biochemical and functional analyses revealed lactic acidosis, complex I (CI) assembly and enzyme deficiency, and a loss of NDUFV1 protein. Complementation assays restored the NDUFV1 protein, CI assembly, and CI enzyme levels. The clinical and radiological features of this case are compatible with the phenotype of LS and LBSL associated with NDUFV1 mutations.

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., Nine newborns and 46 individuals with 33 novel variants, and nine newborns and 10 individuals with eight other variants not registered in the FD database were traced and the information on symptoms, treatments, and outcomes was analyzed. Thirty‐eight of 46 individuals with 33 novel variants had symptoms and received enzyme replacement therapy and/or chaperone treatment.

In Japan, carnitine palmitoyltransferase II (CPTII) deficiency has been included as one of the primary target diseases in the expanded newborn mass screening program since 2018. However, many cases of the severe infantile hepatocardiomuscular form of CPTII deficiency showed severe neurodevelopmental delay or sudden death, which indicated that management of CPTII deficiency in the acute phase remains to be studied in detail. Herein, we discuss two cases diagnosed by newborn mass screening. Patient 1 was under strict clinical management from the neonatal period, with >20 admissions in 14 months, while Patient 2 was managed using a relatively relaxed approach, with only 2 admissions in the same period. Patient 1 showed normal development; however, Patient 2 expired at the age of 1 year 2 months. To develop strategies for preventing sudden deaths in patients with CPTII deficiency, this retrospective study focused on detailed clinical management practices and biochemical findings during the acute phase. We also investigated the correlation between conventional biomarkers (such as creatine kinase) and long-chain acylcarnitines. We propose that strict monitoring and immediate medical attention, even in case of slight fever or minor abdominal symptoms, can help prevent sudden death in patients with CPTII deficiency. Considering the higher morbidity rate of such patients, strict and acute management of CPTII deficiency cannot be overemphasized.

Background Hepatocerebral mitochondrial DNA depletion syndrome (MTDPS) is a disease caused by defects in mitochondrial DNA maintenance and leads to liver failure and neurological complications during infancy. Liver transplantation (LT) remains controversial due to poor outcomes associated with extrahepatic symptoms. The purposes of this study were to clarify the current clinical and molecular features of hepatocerebral MTDPS and to evaluate the outcomes of LT in MTDPS patients in Japan. Results We retrospectively assessed the clinical and genetic findings, as well as the clinical courses, of 23 hepatocerebral MTDPS patients from a pool of 999 patients who were diagnosed with mitochondrial diseases between 2007 and 2019. Causative genes were identified in 18 of 23 patients: MPV17 (n = 13), DGUOK (n = 3), POLG (n = 1), and MICOS13 (n = 1). Eight MPV17-deficient patients harbored c.451dupC and all three DGUOK-deficient patients harbored c.143-307_170del335. The most common initial manifestation was failure to thrive (n = 13, 56.5%). The most frequent liver symptom was cholestasis (n = 21, 91.3%). LT was performed on 12 patients, including nine MPV17-deficient and two DGUOK-deficient patients. Among the 12 transplanted patients, five, including one with mild intellectual disability, survived; while seven who had remarkable neurological symptoms before LT died. Five of the MPV17-deficient survivors had either c.149G > A or c.293C > T. Conclusions MPV17 was the most common genetic cause of hepatocerebral MTDPS. The outcome of LT for MTDPS was not favorable, as previously reported, however, patients harboring MPV17 mutations associated with mild phenotypes such as c.149G > A or c.293C > T, and exhibiting no marked neurologic manifestations before LT, had a better prognosis after LT.

Background: We encountered 7 Japanese patients with bile acid synthesis disorders (BASD) over 21 years between 1996 and 2017. Diagnoses were made by bile acid and genetic analyses. We gave low-dose, long-term chenodeoxycholic acid (CDCA) treatment to 5 of the patients, who had 3β-hydroxy-Δ 5 -C 27 -steroid dehydrogenase/isomerase (3β-HSD) deficiency (n=3) or Δ 4 -3-oxosteroid 5β-reductase (5β-reductase) deficiency (n=2). Another patient with the latter diagnosis whose bile acid analyses had mitigating features was maintained on ursodeoxycholic acid according to parental preferences and now remains healthy after discontinuation of treatment. A patient with oxysterol 7α-hydroxylase deficiency developed liver failure and fully recovered after successful liver transplantation. We used clinical records to clarify long-term outcome and value of CDCA in the other patients. Efficacy of CDCA treatment was evaluated in the 5 patients given a low dose (5 to 10 mg/kg/day) for a long term. Results: Medians with ranges of current patient ages and duration of CDCA treatment are10 years (8 to 43) and 10 years (8 to 21), respectively. All 7 patients, who had homozygous or compound heterozygous mutations in the HSD3B7 , SRD5B1 , or CYP7B1 gene, are currently in good health without liver dysfunction. In the 5 patients with CDCA treatment, hepatic function gradually improved following initiation. No adverse effects were noted. Conclusions: We concluded that low-dose CDCA treatment is effective in 3β-HSD deficiency and 5β-reductase deficiency, as cholic acid has been in other countries. BASD carry a good prognosis following early diagnosis and initiation of long-term, low-dose CDCA treatment.

Background Deafness, dystonia, and cerebral hypomyelination (DDCH) is an X‐linked disorder due to hemizygous mutations of BCAP31. Methods We report an 8‐year‐old boy with DDCH who possibly accompanied mitochondrial dysfunction. Clinical evaluation, respiratory chain enzyme assay, and whole exome sequencing analysis were performed. Results Mitochondrial dysfunction was suspected by respiratory chain enzyme assay on his cultured skin fibroblasts which showed significantly decreased complex I enzyme activity. Whole exome sequencing analysis revealed a recurrent BCAP31 mutation (c.97C>T:p.Gln33*) which confirmed the diagnosis of DDCH for the patient. Conclusion We speculate that mitochondrial dysfunction may be a feature in patients with DDCH., Deafness, dystonia, and cerebral hypomyelination (DDCH) is an X‐linked disorder due to hemizygous mutations of BCAP31. Mitochondrial dysfunction may be associated with DDCH.

Leigh syndrome, which is a common phenotype of pediatric mitochondrial disease, is a progressive neurodegenerative disease. The typical neuroimaging findings of Leigh syndrome include bilateral symmetric lesions in the basal ganglia and/or the brainstem. However, there are a few reports on spinal cord involvement in patients with Leigh syndrome. In the present case, magnetic resonance imaging (MRI) obtained during infancy revealed symmetric lesions in the substantia nigra of a patient with Leigh syndrome with an NDUFA1 mutation; lesions of the bilateral putamen and brainstem were subsequently observed. Additionally, our patient presented large and extended spinal cord lesions. Therefore, this case is suggesting that we should consider the occurrence of spinal cord lesions as an atypical finding in Leigh syndrome.

Aims To evaluate comprehensively the use of the glycated albumin to HbA1c ratio for estimation of glycaemic control in the previous month. Methods A total of 306 children with Type 1 diabetes mellitus underwent ≥10 simultaneous measurements of glycated albumin and HbA1c . Correlation and concordance rates were examined between HbA1c measurements taken 1 month apart (ΔHbA1c ) and glycated albumin/HbA1c ratio fluctuations were calculated as Z-scores from the cohort value at enrolment of this study cohort (method A) or the percent difference from the individual mean over time (method B). Results Fluctuations in glycated albumin/HbA1c ratio (using both methods) were weakly but significantly correlated with ΔHbA1c , whereas concordance rates were significant for glycaemic deterioration but not for glycaemic improvement. Concordance rates were higher using method B than method A. Conclusions The glycated albumin/HbA1c ratio was able to estimate glycaemic deterioration in the previous month, while estimation of glycaemic improvement in the preceding month was limited. Because method B provided a better estimate of recent glycaemic control than method A, the individual mean of several measurements of the glycated albumin/HbA1c ratio over time may also identify individuals with high or low haemoglobin glycation phenotypes in a given population, such as Japanese children with Type 1 diabetes, thereby allowing more effective diabetes management.

Aim: Children with Familial Hypercholesterolemia (FH) are widely prescribed statins, and it has been suggested that the effects of statins differ among ethnicities. We compared the efficacy and safety of pitavastatin in children and adolescents with FH in clinical trials conducted in Japan and Europe. Methods: Low-density lipoprotein cholesterol (LDL-C) reductions, adjusted for confounding factors, and safety were compared between the studies in Japan and Europe. In the Japanese study, 14 males with heterozygous FH, aged 11.8 ± 1.6 years, were randomized to 52-week double-blind treatment with 1 or 2 mg/day pitavastatin. In the European study, 106 children and adolescents with high risk hyperlipidemia (103 heterozygous FH), aged 10.6 ± 2.9 years, were randomized to 12-week double-blind treatment with 1, 2 or 4 mg/day pitavastatin or placebo; 84 of these patients and 29 new patients participated in a 52-week open-label extension study. Results: Age, body weight and baseline LDL-C were identified as factors influencing LDL-C reduction. There were no significant differences in the adjusted mean percentage reduction in LDL-C in Japanese and European children by pitavastatin (24.5% and 23.6%, respectively at 1 mg/day and 33.5% and 30.8%, respectively at 2 mg/day). Pitavastatin was well tolerated without any difference in the frequency or nature of adverse events between the treatment groups, or between the studies. Conclusion: There were no significant differences between the efficacy or safety of pitavastatin in Japanese and European children and adolescents with FH, suggesting no relevant ethnic differences in the safety or efficacy of pitavastatin.

The diagnosis of Barth syndrome is challenging owing to the wide phenotypic spectrum with allelic heterogeneity. Here we report 3 cases of Barth syndrome with phenotypic and allelic heterogeneity that were diagnosed by different approaches, including whole exome sequencing and final confirmation by reverse-transcription polymease chain reaction.

Biallelic 4-hydroxyphenylpyruvate dioxygenase-like protein (HPDL) variants were recently reported as a cause of progressive and incurable neurodegenerative diseases ranging from neonatal-onset leukoencephalopathy with severe neurodevelopmental delay to spastic paraplegia. Although the physiological function of HPDL remains unknown, its subcellular localization in the mitochondria has been reported. Here, we report a case of HPDL-related neurological disease that was clinically and neuroimaging compatible with Leigh syndrome, previously unreported, and was treated with a ketogenic diet.

Alpha-thalassemia X-linked intellectual disability (ATR-X) syndrome is caused by a mutation in ATRX, which is essential for proper chromatin remodeling. ATRX dysfunction leads to dysregulation of many genes due to abnormal chromatin remodeling, and causes a multisystem disorder in patients with ATR-X. Because mitochondrial disorders also show multisystem involvement, whether mitochondrial function is affected in patients with ATR-X is of interest. Here, we report a case of a 4-year-old male with a mutation (NM_000489.4: c.736C > T p.Arg246Cys) in ATRX, who showed mitochondrial dysfunction with complex I deficiency. The results from our study suggest that target genes of the ATRX protein may include those responsible for mitochondrial function, and mitochondrial dysfunction may contribute to some ATR-X phenotypes.

Sapropterin dihydrochloride (SD) may be a new treatment option for women with phenylketonuria (PKU) who plan to become pregnant. We report the first Japanese case of maternal PKU treated with SD. The patient was administered SD at 10–20 mg/kg/day, which increased phenylalanine tolerance during the pregnancy and lactation. No adverse events occurred, and she delivered a healthy neonate. Normal growth and development of the child confirms the efficacy and safety of SD. Keywords: Maternal phenylketonuria, Sapropterin dihydrochloride, Growth and development

Background Holoprosencephaly (HPE) is a congenital malformation with an estimated prevalence of 0.10-6.06 per 10 000 births but with no nationwide data specific to Japan. Methods This nationwide retrospective questionnaire survey was conducted from 2011 to 2013. All 467 training hospitals for perinatal and neonatal care certified by the Japan Society of Perinatal and Neonatal Medicine were contacted. The birth prevalence rate (BPR) was assessed from the primary survey and clinical characteristics from the secondary survey. Results We received valid responses from 253 hospitals in the primary survey (54.6%). Of 390 342 live births, 60 were diagnosed with HPE (23 males and 37 females), resulting in an actual BPR of 1.54 per 10 000 live births. The point estimate for HPE cases was 100 (95% confidence interval [CI]: 80.7-120), and the estimated BPR of HPE was calculated to be 0.32 per 10 000 live births (95% CI: 0.26-0.38) based on 3 117 853 live births according to Japanese national statistics during the study period. In the secondary survey, we obtained data for 49 cases (19 males and 30 females). Of these, 20 were alobar (40.8%), 20 were semilobar (40.8%), five were lobar (10.4%), and four were of unknown type. Genetic examination was performed in 37 of the 49 HPE patients and revealed that chromosomes 13, 18, and 7 were affected in eight, six, and four patients, respectively. Conclusions This is the most extensive survey on holoprosencephaly to date in Japan. The estimated BPR was consistent with that reported in previous research.

A female infant born at 36 weeks gestational age with birthweight 2135 g, and who developed respiratory disorder, hyperlactacidemia and hypertrophic cardiomyopathy after birth, was admitted to hospital at 3 days of age. After admission, bilious emesis, abdominal distention, and passage disorder of the gastrointestinal tract were resistant to various drugs. Exploratory laparotomy was performed at 93 days of age, but no organic lesions were identified and normal Meissner/Auerbach nerve plexus was confirmed, which led to a clinical diagnosis of chronic intestinal pseudo-obstruction (CIPO). She was diagnosed with mitochondrial respiratory chain complex IV deficiency on histopathology of the abdominal rectus muscle and enzyme activity measurement. This is the first report of a neonate with mitochondrial respiratory chain complex deficiency with intractable CIPO. CIPO can occur in neonates with mitochondrial respiratory chain disorder, necessitating differential diagnosis from Hirschsprung disease.

This paper describes consensus statement by Joint Working Group by Japan Pediatric Society and Japan Atherosclerosis Society for Making Guidance of Pediatric Familial Hypercholesterolemia (FH) in order to improve prognosis of FH.FH is a common genetic disease caused by mutations in genes related to low density lipoprotein (LDL) receptor pathway. Because patients with FH have high LDL cholesterol (LDL-C) levels from the birth, atherosclerosis begins and develops during childhood which determines the prognosis. Therefore, in order to reduce their lifetime risk for cardiovascular disease, patients with FH need to be diagnosed as early as possible and appropriate treatment should be started.Diagnosis of pediatric heterozygous FH patients is made by LDL-C ≥140 mg/dL, and family history of FH or premature CAD. When the diagnosis is made, they need to improve their lifestyle including diet and exercise which sometimes are not enough to reduce LDL-C levels. For pediatric FH aged ≥10 years, pharmacotherapy needs to be considered if the LDL-C level is persistently above 180 mg/dL. Statins are the first line drugs starting from the lowest dose and are increased if necessary. The target LDL-C level should ideally be ＜140 mg/dL. Assessment of atherosclerosis is mainly performed by noninvasive methods such as ultrasound.For homozygous FH patients, the diagnosis is made by existence of skin xanthomas or tendon xanthomas from infancy, and untreated LDL-C levels are approximately twice those of heterozygous FH parents. The responsiveness to pharmacotherapy should be ascertained promptly and if the effect of treatment is not enough, LDL apheresis needs to be immediately initiated.

Pearson marrow-pancreas syndrome (PS) is a rare mitochondrial disorder. Impaired mitochondrial respiratory chain complexes (MRCC) differ among individuals and organs, which accounts for variable clinical pictures. A subset of PS patients develop 3-methylglutaconic aciduria (3-MGA-uria), but the characteristic symptoms and impaired MRCC remain unknown. Our patient, a girl, developed pancytopenia, hyperlactatemia, steatorrhea, insulin-dependent diabetes mellitus, liver dysfunction, Fanconi syndrome, and 3-MGA-uria. She died from cerebral hemorrhage at 3 years of age. We identified a novel 5.4-kbp deletion of mitochondrial DNA. The enzymatic activities of MRCC I and IV were markedly reduced in the liver and muscle and mildly reduced in skin fibroblasts and the heart. To date, urine organic acid analysis has been performed on 29 PS patients, including our case. Eight patients had 3-MGA-uria, while only one patient did not. The remaining 20 patients were not reported to have 3-MGA-uria. In this paper, we included these 20 patients as PS patients without 3-MGA-uria. PS patients with and without 3-MGA-uria have similar manifestations. Only a few studies have examined the enzymatic activities of MRCC.No clinical characteristics distinguish between PS patients with and without 3-MGA-uria. The correlation between 3-MGA-uria and the enzymatic activities of MRCC remains to be elucidated.• The clinical characteristics of patients with Pearson marrow-pancreas syndrome and 3-methylglutaconic aciduria remain unknown.• No clinical characteristics distinguish between Pearson marrow-pancreas syndrome patients with and without 3-methylglutaconic aciduria.

AIM To examine the contribution of PTPN2 coding variants to the risk of childhood-onset Type 1A diabetes. METHODS PTPN2 mutation analysis was carried out for 169 unrelated Japanese people with childhood-onset Type 1A diabetes. We searched for coding variants that were absent or extremely rare in the general population and were scored as damaging by multiple in silico programs. We performed mRNA analysis and three-dimensional structural prediction of the detected variants, when possible. We also examined possible physical links between these variants and previously reported risk SNPs as well as clinical information from variant-positive children. RESULTS One frameshift variant (p.Q286Yfs*24) and two probably damaging missense substitutions (p.C232W and p.R350Q) were identified in one child each. Of these, p.Q286Yfs*24 and p.C232W were hitherto unreported, while p.R350Q accounted for 2/121,122 alleles of the exome datasets. The p.Q286Yfs*24 variant did not encode stable mRNA, and p.C232W appeared to affect the structure of the tyrosine-protein phosphatase domain. The three variants were physically unrelated to known risk SNPs. The variant-positive children manifested Type 1A diabetes without additional clinical features and invariably carried risk human leukocyte antigen alleles. CONCLUSIONS The results provide the first indication that PTPN2 variants contribute to the risk of Type 1A diabetes, independently of known risk SNPs. PTPN2 coding variants possibly induce non-specific Type 1A diabetes phenotypes in individuals with human leukocyte antigen-mediated disease susceptibility. Our findings warrant further validation.

Introduction: Mitochondrial dysfunction results in a wide range of organ disorders through diverse genetic abnormalities. We herein present the detailed clinical course of an infant admitted for extensive, rapidly progressing white matter lesions and hypertrophic cardiomyopathy due to a BOLA3 gene mutation. Case: A 6-month-old girl with no remarkable family or past medical history until 1 month prior presented with developmental regression and feeding impairment. Ultrasound cardiography and brain magnetic resonance imaging (MRI) respectively disclosed the presence of hypertrophic cardiomyopathy and symmetrical deep white matter lesions. She was transferred to our hospital at age 6 months. High lactate levels in her cerebrospinal fluid suggested mitochondrial dysfunction. Despite vitamin supplementation therapy followed by a ketogenic diet, the patient began exhibiting clusters of myoclonic seizures and respiratory failure. Brain and spinal cord MRI revealed rapid progression of the white matter lesions. She died at 10 months of age. Fibroblasts obtained pre-mortem displayed low mitochondrial respiratory chain complex I and II activity. A homozygous H96R (c. 287 A > G) mutation was identified in the BOLA3 gene. Discussion: No reported case of a homozygous BOLA3 gene mutation has survived past 1 year of life. BOLA3 appears to play a critical role in the electron transport system and production of iron-sulfur clusters that are related to lipid metabolism and enzyme biosynthesis.

Background Carnitine palmitoyltransferase (CPT) II deficiency is one of the most common forms of mitochondrial fatty acid oxidation disorder (FAOD). However, newborn screening (NBS) for this potentially fatal disease has not been established partly because reliable indices are not available. Methods We diagnosed CPT II deficiency in a 7-month-old boy presenting with hypoglycemic encephalopathy, which apparently had been missed in the NBS using C16 and C18:1 concentrations as indices. By referring to his acylcarnitine profile from the NBS, we adopted the (C16 + C18:1)/C2 ratio (cutoff 0.62) and C16 concentration (cutoff 3.0 nmol/mL) as alternative indices for CPT II deficiency such that an analysis of a dried blood specimen collected at postnatal day five retroactively yielded the correct diagnosis. Thereafter, positive cases were assessed by measuring (1) the fatty acid oxidation ability of intact lymphocytes and/or (2) CPT II activity in the lysates of lymphocytes. The diagnoses were then further confirmed by genetic analysis. Results The disease was diagnosed in seven of 21 newborns suspected of having CPT II deficiency based on NBS. We also analyzed the false-negative patient and five symptomatic patients for comparison. Values for the NBS indices of the false-negative, symptomatic patient were lower than those of the seven affected newborns. Although it was difficult to differentiate the false-negative patient from heterozygous carriers and false-positive subjects, the fatty acid oxidation ability of the lymphocytes and CPT II activity clearly confirmed the diagnosis. Among several other indices proposed previously, C14/C3 completely differentiated the seven NBS-positive patients and the false-negative patient from the heterozygous carriers and the false-positive subjects. Genetic analysis revealed 16 kinds of variant alleles. The most prevalent, detected in ten alleles in nine patients from eight families, was c.1148T > A (p.F383Y), a finding in line with those of several previous reports on Japanese patients. Conclusions These findings suggested that CPT II deficiency can be screened by using (C16 + C18:1)/C2 and C16 as indices. An appropriate cutoff level is required to achieve adequate sensitivity albeit at the cost of a considerable increase in the false-positive rate, which might be reduced by using additional indices such as C14/C3.

We report the first case of Leigh syndrome (LS) with Fukuyama congenital muscular dystrophy (FCMD). A neonate suffered from lactic acidosis and subsequently presented with poor feeding, muscle weakness, hypotonia, cardiopulmonary dysfunction, and hydrocephalus. He died at 17 months. The findings of brain magnetic resonance imaging indicated some specific features of both LS and FCMD, and FCMD gene mutation was detected. Decreased mitochondrial respiratory complex I and II activity was noted. Mitochondrial DNA sequencing showed no pathogenic mutation. A case with complex I+II deficiency has rarely been reported, suggesting a nuclear gene mutation.

Influence of hyperphenylalaninemia on lipoproteins in early life remains unclear.We enrolled 24 phenylalanine hydroxylase (PAH)-deficient children who were classified into a phenylketonuria (PKU) group (n=12) lacking PAH activity and a benign hyperphenylalaninemia (HPA) group (n=12) having partial PAH activity, and their 11 non-affected siblings. We measured serum total-cholesterol, low-density lipoprotein (LDL)-cholesterol, and high-density lipoprotein (HDL)-cholesterol levels together with apolipoproteins for the first year of life, and compared them with those of 30 age-matched healthy controls.The affected groups invariably had lower cholesterol levels than non-affected groups. At birth, HDL-cholesterol decrease was greatest and predominated over the LDL-cholesterol decrease: total cholesterol, 28/36% decrease to the control level in HPA/PKU; HDL-cholesterol, 33/51%; LDL-cholesterol, 20/28%. At 3months, the opposite changes were observed: total cholesterol, 16/28%; HDL-cholesterol, 13/23%; LDL-cholesterol, 16/33%. At 12months, LDL were still significantly lower in both groups (8/18%, p.05 and .001), although HDL was significantly decreased only in the PKU group (15%, p.05). Apolipoprotein A-I/A-II and B changed respectively in accordance with HDL-cholesterol and LDL-cholesterol changes. Despite similar phenylalanine levels, the PKU group invariably had lower cholesterol concentrations than the HPA group had.Irrespective of phenylalanine concentrations, lipoprotein synthesis in PAH-deficient children, particularly in PKU children, was suppressed in early life.

We present characteristic magnetic resonance imaging (MRI) features in a pediatric female patient with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Muscle weakness developed at 8 years old and fluctuated during the clinical course over 7 years. Electrophysiological studies showed a demyelination pattern with moderately delayed nerve conduction velocity, as well as dispersion phenomenon. MRI showed marked changes in thickening of the spinal nerve roots and their peripheral nerves in the lumber and brachial plexuses, as well as in the bilateral trigeminal nerves. It is suggested that these MRI features are characteristic and strongly supportive of the diagnosis of CIDP with a prolonged clinical course.

The patient had hepatomegaly with liver dysfunction at the age of 1 month. Magnetic resonance imaging performed at the age of 1 year showed multiple nodules of varying size in his liver. We were able to examine the mitochondrial respiratory chain function in the liver biopsy samples because all other differential diagnoses for hepatic cirrhosis had been ruled out. Complex I and IV activities were below the normal level (

In two Japanese infants with neonatal cholestasis, 3-oxo-Δ(4)-steroid 5β-reductase deficiency was diagnosed based on mutations of the SRD5B1 gene. Unusual bile acids such as elevated 3-oxo-Δ(4) bile acids were detected in their serum and urine by gas chromatography-mass spectrometry. We studied effects of oral chenodeoxycholic acid treatment.SRD5B1 gene analysis used peripheral lymphocyte genomic DNA. Diagnosis and treatment of these two patients were investigated retrospectively and prospectively investigated.With respect to SRD5B1, one patient was heterozygous (R266Q, a novel mutation) while the other was a compound heterozygote (G223E/R261C). Chenodeoxycholic acid treatment was effective in improving liver function and decreasing unusual bile acids such as 7α-hydroxy- and 7α,12α-dihydroxy-3-oxo-4-cholen-24-oic acids in serum and urine.Primary bile acid treatment using chenodeoxycholic acid was effective for these patients treated in early infancy before the late stage of chronic cholestatic liver dysfunction.

Background: Succinyl-coenzyme A ligase (SUCL) is a mitochondrial enzyme that catalyses the reversible conversion of succinyl-coenzyme A to succinate. SUCL consists of an α subunit, encoded by SUCLG1, and a β subunit, encoded by either SUCLA2 or SUCLG2. Recently, mutations in SUCLG1 or SUCLA2 have been identified in patients with infantile lactic acidosis showing elevated urinary excretion of methylmalonate, mitochondrial respiratory chain (MRC) deficiency, and mitochondrial DNA depletion. Methods: Case description of a Japanese female patient who manifested a neonatal-onset lactic acidosis with urinary excretion of methylmalonic acid. Enzymatic analyses (MRC enzyme assay and Western blotting) and direct sequencing analysis of SUCLA2 and SUCLG1 were performed. Results: MRC enzyme assay and Western blotting showed that MRC complex I was deficient. SUCLG1 mutation analysis showed that the patient was a compound heterozygote for disease-causing mutations (p.M14T and p.S200F). Conclusion: For patients showing neonatal lactic acidosis and prolonged mild methylmalonic aciduria, MRC activities and mutations of SUCLG1 or SUCLA2 should be screened for.

The mechanism underlying the development of osteopenia or osteoporosis in longstanding phenylketonuria (PKU) remains to be clarified. We investigated the details of bone metabolism in 21 female and 13 male classical PKU patients aged 20–35 years. Vitamin D (VD), parathyroid hormone (PTH), bone turnover markers, and daily nutrient intake were examined. The patients had lower daily energy and protein intake than did the age-matched controls (22 women, 14 men), but their respective fat, VD, and calcium intake did not differ. Serum 1,25-dihydroxy VD and 25-hydroxy VD levels in female and male patient groups were significantly higher and lower than those in respective control groups (females, P

Background While the association between scoliosis and impairments in cardiac and respiratory function has been well characterized in clinical practice and research, the potential effect of scoliosis on urinary tract structure and renal function has received little attention. Therefore, the purpose of our study was to evaluate the preoperative clinical characteristics of urinary tract structure and renal function in pediatric patients with idiopathic scoliosis, using a combination of blood tests, urinalyses, and imaging procedures. Methods Preoperative measures of urinary tract structure and renal function were obtained for 16 patients, 13 to 17 years old, scheduled for corrective surgery for idiopathic scoliosis. Preoperative assessment included blood test and urinalyses, combined with structural imaging by ultrasound (US), magnetic resonance (MRI), magnetic resonance urography (MRU), and radioisotope tracing (RI), using technetium-99mTC-mercaptoacetyltriglycine (99mTC-MAG3). Differences in blood and urine tests between patients with and without urinary tract obstruction (UTO) were evaluated for significance using Mann-Whitney U test. Results For all 16 patients, blood tests and MRU results were within normal limits. Evidence of dilatation of the renal pelvis was identified by US imaging in 8 (50.0%) patients. UTO was identified by RI in 6 (37.5%) patients. UTO was associated with elevated levels of β2-microglobulin concentration. A urinary β2-microglobulin concentration above 0.7μg/mg Cr differentiated patients with UTO, from those without UTO, with a sensitivity of 100% and specificity of 70%. Conclusions β2-microglobulin concentration may provide a useful marker to screen for asymptomatic UTO in patients with idiopathic scoliosis. This article is protected by copyright. All rights reserved.

Background A nationwide, multicenter and observational study was retrospectively conducted to evaluate the clinical utility of cepharanthin (CEP) therapy for pediatric patients with chronic immune thrombocytopenia (ITP). Methods Clinical and laboratory data of 46 Japanese patients less than 16 years of age were analyzed, who were diagnosed as having chronic ITP in 14 hospitals during the 2001-2011 decade, and were treated with CEP for more than 12 months. Results The median daily dose of CEP was 1 mg/kg (0.12–2). The platelet counts prior to CEP therapy were 20.5 ×109/L (IQR 8.3-53.0), and were then significantly increased to 58.5 ×109/L (IQR 22.8-115.0) and 69.0 ×109/L (IQR 23.0-134.0) after 12 and 24 months of the treatment course, respectively. No life-threatening bleedings or moderate to severe adverse events were reported. Of 38 patients who received both corticosteroids (CS) and CEP, 17 patients (45%) were weaned from CS, and 15 patients (39%) attained the reduced dose of CS. The period from the start of CEP therapy to the stop of CS was median 413 days (range 49–1734) in patients who were weaned from CS. Conclusions CEP alone or combined therapy with CS was found to be useful for the management of pediatric patients with chronic ITP. This article is protected by copyright. All rights reserved.

Aim The purpose of this study was to evaluate the efficacy and safety of LIVALO tablets (pitavastatin) in Japanese male children with heterozygous familial hypercholesterolemia (FH). Methods A multicenter, randomized, double-blind, parallel study was conducted in 14 male children 10-15 years of age with heterozygous FH. Pitavastatin (1 mg/day or 2 mg/day) was administered orally for 52 weeks.The primary endpoint was the percent change in the LDL-cholesterol (LDL-C) concentrations from baseline to endpoint (repeated measures ANCOVA at Weeks 8 and 12). Secondary endpoints included the percentage of patients who achieved the target LDL-C concentration and percent changes in the levels of lipoprotein and lipid parameters at the visit performed at 52 weeks. Results The percent change in LDL-C from baseline (mean 258 mg/dL for all patients) to the endpoint was -27.3% (95%CI; -34.0, -20.5) and -34.3% (95%CI; -41.0, -27.5) in the patients receiving 1 mg and 2 mg of pitavastatin, respectively. Stable reductions in the total cholesterol (TC), non-HDL cholesterol (non-HDL-C), apolipoprotein B (Apo-B) and LDL-C levels and non-HDL-C/HDL-C and Apo-B/Apo-A1 ratios were observed up to 52 weeks in both groups. One patient in each dose group (14%) reached the treatment target level of 130 mg/dL.Adverse events were observed in seven (100%) patients receiving 1 mg and five (71%) patients receiving 2 mg of pitavastatin, although none were considered related to the study treatment. One patient in the 1 mg group reported a musculoskeletal AE; however, it was attributed to recent excessive exercise. Conclusions Pitavastatin significantly reduced the LDL-C levels and was well tolerated when administered at usual adult doses in 14 male children 10-15 years of age with heterozygous FH. Pitavastatin is a promising therapeutic agent for pediatric dyslipidemia with few safety concerns.