Publications by authors named "Akihiko Miyauchi"

Patatin-like phospholipase domain-containing lipase 8 (PNPLA8), one of the calcium-independent phospholipase A2 enzymes, is involved in various physiological processes through the maintenance of membrane phospholipids. Biallelic variants in PNPLA8 have been associated with a range of paediatric neurodegenerative disorders. However, the phenotypic spectrum, genotype-phenotype correlations and the underlying mechanisms are poorly understood.

View Article and Find Full Text PDF

Mitochondrial diseases are mainly caused by dysfunction of mitochondrial respiratory chain complexes and have a variety of genetic variants or phenotypes. There are only a few approved treatments, and fundamental therapies are yet to be developed. Leigh syndrome (LS) is the most severe type of progressive encephalopathy.

View Article and Find Full Text PDF
Article Synopsis
  • * The study demonstrated that apomorphine effectively prevents ferroptosis—a type of cell death—in both fibroblasts from mitochondrial disease patients and normal controls, which is marked by key biological indicators like PTGS2.
  • * Notably, the anti-ferroptosis effects of apomorphine are independent of its action on dopamine receptors, showcasing its potential as a powerful inhibitor of ferroptotic cell death regardless of dopaminergic activity.
View Article and Find Full Text PDF

We discovered biallelic intragenic structural variations (SVs) in by applying long-read whole genome sequencing to an exome-negative patient with developmental and epileptic encephalopathy (DEE). We also found another DEE patient carrying a biallelic (homozygous) single-nucleotide variant (SNV) in that was detected by exome sequencing. heterozygous recurrent missense variants with gain-of-function or heterozygous entire duplication of are known causes of epilepsy, but biallelic SNVs/SVs have never been described.

View Article and Find Full Text PDF
Article Synopsis
  • * A study measured levels of reduced and oxidized CoQ in skin fibroblasts from 24 patients with various mitochondrial diseases, including primary CoQ deficiency and different respiratory chain complex deficiencies.
  • * Results showed decreased total CoQ levels in primary CoQ deficiency patients but unchanged reduced/total CoQ ratios, while patients with other deficiencies exhibited higher reduced/total CoQ ratios, indicating that CoQ measurement can aid in diagnosing primary CoQ deficiency and reflect the metabolic state in mitochondrial diseases.
View Article and Find Full Text PDF
Article Synopsis
  • Hypertrophic cardiomyopathy, a serious heart condition linked to mitochondrial disorders, can have a 40% morbidity rate in neonates, with high mortality due to lack of treatment options.
  • A case study of a male infant with a neonatal mitochondrial disorder showed significant health improvements after treatment with low-dose propranolol and cibenzoline, an antiarrhythmic drug, for his hypertrophic obstructive cardiomyopathy.
  • After six weeks of treatment, the infant's heart condition improved, as indicated by lower peak velocity measures and reduced levels of a heart failure biomarker, suggesting cibenzoline could be a viable treatment option for such cases.
View Article and Find Full Text PDF
Article Synopsis
  • Adrenoleukodystrophy (ALD) is a genetic disorder that leads to the degeneration of brain white matter due to mutations affecting the transport of fatty acids, particularly very-long-chain fatty acids (VLCFA).
  • The patient in this case was diagnosed with the severe childhood form of ALD at age 5, and although his younger brother tested positive for the same mutation, he showed no symptoms until later imaging indicated brain lesions.
  • After receiving unrelated cord blood transplantation, the patient's donor cell levels remained low, yet his neurological condition did not worsen over 7 years, suggesting that even minimal donor cell presence may help prevent disease progression.
View Article and Find Full Text PDF

Background: The DYNC1H1 gene encodes the heavy chain of cytoplasmic dynein 1, a core structure of the cytoplasmic dynein complex. Dominant DYNC1H1 mutations are implicated in Charcot-Marie-Tooth disease, axonal, type 20, spinal muscular atrophy, lower extremity-predominant 1, and autosomal dominant mental retardation 13 with neuronal migration defects. We report two patients with DYNC1H1 mutations who had intractable epilepsy and intellectual disability (ID), one with and one without pachygyria.

View Article and Find Full Text PDF

Intravenous corticosteroids have been regarded as the first-line therapy of anti-myelin-oligodendrocyte glycoprotein antibody (MOG-Ab)-positive acute disseminated encephalomyelitis (ADEM). While steroids are the first-choice therapy, MOG-Ab-positive ADEM has a high relapse rate. In some cases, MOG-Ab-positive ADEM relapses even in a low-MOG-Abs state.

View Article and Find Full Text PDF

We report on the validation of a mitochondrial gene therapeutic strategy using fibroblasts from a Leigh syndrome patient by the mitochondrial delivery of therapeutic mRNA. The treatment involves delivering normal ND3 protein-encoding mRNA as a therapeutic RNA to mitochondria of the fibroblasts from a patient with a T10158C mutation in the mtDNA coding the ND3 protein, a component of the mitochondrial respiratory chain complex I. The treatment involved the use of a liposome-based carrier (a MITO-Porter) for delivering therapeutic RNA to mitochondria via membrane fusion.

View Article and Find Full Text PDF

De novo variants (DNVs) cause many genetic diseases. When DNVs are examined in the whole coding regions of genes in next-generation sequencing analyses, pathogenic DNVs often cluster in a specific region. One such region is the last exon and the last 50 bp of the penultimate exon, where truncating DNVs cause escape from nonsense-mediated mRNA decay [NMD(-) region].

View Article and Find Full Text PDF

Mitochondrial disease is a genetic disorder in which individuals suffer from energy insufficiency. The various clinical phenotypes of mitochondrial disease include Leigh syndrome (LS), myopathy encephalopathy lactic acidosis and stroke-like episodes (MELAS). Thus far, no curative treatment is available, and effective treatment options are eagerly awaited.

View Article and Find Full Text PDF

In patients with aromatic l-amino acid decarboxylase (AADC) deficiency, a decrease in catecholamines and serotonin levels in the brain leads to developmental delay and movement disorders. The beneficial effects of gene therapy in patients from 1 to 8 years of age with homogeneous severity of disease have been reported from Taiwan. We conducted an open-label phase 1/2 study of population including adolescent patients with different degrees of severity.

View Article and Find Full Text PDF

Background: The effect of rituximab on acute disseminated encephalomyelitis (ADEM) followed by recurrent optic neuritis (ON) is not yet known.

Patient: We are reporting the case of a 4-year-old Japanese girl who was diagnosed with anti-myelin oligodendrocyte glycoprotein (MOG) antibody positive ADEM followed by recurrent ON. She developed altered mental status, left facial paralysis, left paresis, and experienced three episodes of ON.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

Background: Leigh syndrome is a mitochondrial disease caused by respiratory chain deficiency, and there are no proven effective therapies. EPI-743 is a potent cellular oxidative stress protectant and results of clinical trials for mitochondrial diseases are accumulating.

Case: At 5months, a girl presented with the scarce eye movement and diminished muscle tone.

View Article and Find Full Text PDF

Background: The potassium voltage-gated channel subfamily Q member 2 (KCNQ2) gene has been reported to be associated with various types of epilepsy, including benign familial neonatal seizure (BFNS), early infantile epileptic encephalopathy (EIEE), and unclassified early onset encephalopathies. We herein report a patient with early myoclonic encephalopathy (EME) caused by a KCNQ2 mutation.

Case Report: A male infant started to exhibit erratic myoclonus several days after birth and apnea attacks lasting for seconds with desaturation.

View Article and Find Full Text PDF
Article Synopsis
  • Niemann-Pick disease type C (NPC) is a rare genetic disorder caused by mutations in NPC1 or NPC2 genes, leading to problems with lipid management in cells.
  • Miglustat is a medication that helps alleviate neurological symptoms of NPC and was approved in Japan in 2012, showing promising results when started early.
  • A case study reports the youngest patient (4 months old) treated with miglustat, who remained stable with no new neurological symptoms and improved pulmonary function, highlighting the benefits of early treatment.
View Article and Find Full Text PDF
Article Synopsis
  • A 19-year-old female experienced worsening chorea linked to a GNAO1 mutation, which did not improve with several anticonvulsants.
  • She developed neuroleptic malignant syndrome due to the medication tiapride but showed significant improvement after starting topiramate at age 18.
  • Topiramate is suggested as the first-line treatment for severe chorea related to GNAO1 mutations because of its effectiveness and fewer complications compared to neuroleptics and deep brain stimulation.
View Article and Find Full Text PDF

5-Aminosalicylic acid preparations have been used as first-line drugs for treatment of ulcerative colitis (UC). However, some patients with UC present with exacerbation of symptoms because of allergy to mesalazine. Diagnosis of mesalazine allergy in active UC may be challenging because its symptoms mimic those of UC.

View Article and Find Full Text PDF

Background: Aromatic l-amino acid decarboxylase (AADC) deficiency is an autosomal recessive disorder, caused by defects in the DDC gene. AADC catalyzes the synthesis of the neurotransmitters dopamine and serotonin from l-dopa and 5-HT respectively. Most patients are bed ridden for life, with little response to treatment.

View Article and Find Full Text PDF

We are reporting on a case of pediatric anti-NMDAR encephalitis with autonomic instability. The patient showed little response to first-line treatment of steroid and IVIG. We initiated plasma exchange, also a first-line treatment.

View Article and Find Full Text PDF

Using comparative genomic hybridization analysis for an autism spectrum disorder (ASD) patient, a 73-Kb duplication at 19q13.33 (nt. 49 562 755-49 635 956) including LIN7B and 5 other genes was detected.

View Article and Find Full Text PDF

We report the case of a 5-year-old Japanese girl who initially had acute disseminated encephalomyelitis (ADEM) and was positive for the myelin oligodendrocyte glycoprotein (MOG) antibodies and developed unilateral optic neuritis (ON) 71 days after ADEM onset. The patient's serum was positive for the anti-MOG antibodies from the onset of ADEM to the development of ON. This phenotype has been reported in only two previous articles, and the specific mechanism of action of the anti-MOG antibodies is not yet understood.

View Article and Find Full Text PDF

Synopsis of recent research by authors named "Akihiko Miyauchi"

  • - Akihiko Miyauchi's research primarily focuses on genetic and therapeutic advancements related to pediatric neurological disorders, particularly mitochondrial diseases and epilepsy, aiming to better understand the underlying mechanisms and improve treatment options.
  • - Recent studies highlight the role of biallelic variants in genes like PNPLA8 in causing neurodevelopmental issues such as microcephaly, while also exploring innovative therapeutic approaches, such as synthetic aporphine alkaloids for Leigh syndrome and the use of apomorphine in preventing ferroptosis in patients with mitochondrial diseases.
  • - Miyauchi's work incorporates advanced genetic sequencing techniques, like long-read sequencing, to uncover structural variations associated with epilepsy and mitochondrial dysfunctions, thereby enhancing genotype-phenotype correlations in affected pediatric populations.