Yurika Numata

Acute encephalopathy with a truncation mutation in the SCN1A gene: A case report

A girl aged 1 year 9 months had recurrent episodes of febrile status epilepticus. She recovered completely after the first three episodes. However, at 9 months she developed acute encephalopathy resulting in severe neurologic sequelae. Diffusion‐weighted magnetic resonance imaging revealed diffuse high‐intensity signals over the cortex and subcortical white matter in the acute phase and severe diffuse cerebral atrophy in the chronic phase. Mutations were detected in the neuronal voltage‐gated sodium channel alpha subunit type 1 (SCN1A) gene. SCN1A sequence analysis revealed a truncation mutation: ex1‐c.126Adel (D43fs). Our patient was likely afflicted by severe myoclonic epilepsy in infancy, and the fourth episode of status epilepticus was similar to acute encephalopathy. This report provides further insight into the molecular pathophysiology underlying acute encephalopathy.

Brain magnetic resonance imaging and motor and intellectual functioning in 86 patients born at term with spastic diplegia.

Aim  To investigate the association between magnetic resonance imaging (MRI) patterns and motor function, epileptic episodes, and IQ or developmental quotient in patients born at term with spastic diplegia.

Depletion of molecular chaperones from the endoplasmic reticulum and fragmentation of the Golgi apparatus associated with pathogenesis in Pelizaeus-Merzbacher disease

Background: Mutations of proteolipid protein 1 (PLP1) induce endoplasmic reticulum (ER) stress. Results: PLP1 mutants deplete some chaperones from the ER and induce fragmentation of the Golgi apparatus (GA). Conclusion: These changes affect clinical pathology in disease-causing mutations of PLP1. Significance: This work provides a novel insight involving global changes of organelles in pathogenesis of ER stress-related diseases. Missense mutations in the proteolipid protein 1 (PLP1) gene cause a wide spectrum of hypomyelinating disorders, from mild spastic paraplegia type 2 to severe Pelizaeus-Merzbacher disease (PMD). Mutant PLP1 accumulates in the endoplasmic reticulum (ER) and induces ER stress. However, the link between the clinical severity of PMD and the cellular response induced by mutant PLP1 remains largely unknown. Accumulation of misfolded proteins in the ER generally leads to up-regulation of ER chaperones to alleviate ER stress. Here, we found that expression of the PLP1-A243V mutant, which causes severe disease, depletes some ER chaperones with a KDEL (Lys-Asp-Glu-Leu) motif, in HeLa cells, MO3.13 oligodendrocytic cells, and primary oligodendrocytes. The same PLP1 mutant also induces fragmentation of the Golgi apparatus (GA). These organelle changes are less prominent in cells with milder disease-associated PLP1 mutants. Similar changes are also observed in cells expressing another disease-causing gene that triggers ER stress, as well as in cells treated with brefeldin A, which induces ER stress and GA fragmentation by inhibiting GA to ER trafficking. We also found that mutant PLP1 disturbs localization of the KDEL receptor, which transports the chaperones with the KDEL motif from the GA to the ER. These data show that PLP1 mutants inhibit GA to ER trafficking, which reduces the supply of ER chaperones and induces GA fragmentation. We propose that depletion of ER chaperones and GA fragmentation induced by mutant misfolded proteins contribute to the pathogenesis of inherited ER stress-related diseases and affect the disease severity.

Effect of curcumin in a mouse model of Pelizaeus–Merzbacher disease

PLP1 amino acid substitutions cause accumulation of misfolded protein and induce endoplasmic reticulum (ER) stress, causing Pelizaeus-Merzbacher disease (PMD), a hypomyelinating disorder of the central nerve system. Currently no effective therapy is available for PMD. Promoted by its curative effects in other genetic disease models caused by similar molecular mechanisms, we tested if curcumin, a dietary compound, can rescue the lethal phenotype of a PMD mouse model (myelin synthesis deficient, msd). Curcumin was administered orally to myelin synthesis deficit (msd) mice at 180 mg·kg(-1)·day(-1) from the postnatal day 3. We evaluated general and motor status, changes in myelination and apoptosis of oligodendrocytes by neuropathological and biochemical examination, and transcription levels for ER-related molecules. We also examined the pharmacological effect of curcumin in cell culture system. Oral curcumin treatment resulted in 25% longer survival (p<0.01). In addition, oligodendrocytes undergoing apoptosis were reduced in number (p<0.05). However, no apparent improvement in motor function, neurological phenotype, and myelin formation was observed. Curcumin treatment did not change the expression of ER stress markers and subcellular localization of the mutant protein in vitro and/or in vivo. Curcumin partially mitigated the clinical and pathological phenotype of msd mice, although molecular mechanisms underlying this curative effect are yet undetermined. Nonetheless, curcumin may serve as a potential therapeutic compound for PMD caused by PLP1 point mutations.

Hypoperfusion in caudate nuclei in patients with brain–lung–thyroid syndrome

Mutations in NKX2-1 cause neurological, pulmonary, and thyroid hormone impairment. Recently, the disease was named brain-lung-thyroid syndrome. Here, we report three patients with brain-lung-thyroid syndrome. All patients were unable to walk until 24 months of age, and still have a staggering gait, without mental retardation. They have also had choreoathetosis since early infancy. Genetic analysis of NKX2-1 revealed a novel missense mutation (p.Val205Phe) in two patients who were cousins and their maternal families, and a novel 2.6-Mb deletion including NKX2-1 on chromosome 14 in the other patient. Congenital hypothyroidism was not detected on neonatal screening in the patient with the missense mutation, and frequent respiratory infections were observed in the patient with the deletion in NKX2-1. Oral levodopa did not improve the gait disturbance or involuntary movement. The results of (99m)Tc-ECD single-photon emission computed tomography (ECD-SPECT) analyzed using the easy Z-score imaging system showed decreased cerebral blood flow in the bilateral basal ganglia, especially in the caudate nuclei, in all three patients, but no brain magnetic resonance imaging (MRI) abnormalities. These brain nuclear image findings indicate that NKX2-1 haploinsufficiency causes dysfunction of the basal ganglia, especially the caudate nuclei, resulting in choreoathetosis and gait disturbance in this disease.

Attenuation of endoplasmic reticulum stress in Pelizaeus-Merzbacher disease by an anti-malaria drug, chloroquine.

Pelizaeus-Merzbacher disease (PMD) is a hypomyelinating disorder caused by the duplication and missense mutations of the proteolipid protein 1 (PLP1) gene. PLP1 missense proteins accumulate in the endoplasmic reticulum (ER) of premature oligodendrocytes and induce severe ER stress followed by apoptosis of the cells. Here, we demonstrate that an anti-malaria drug, chloroquine, decreases the amount of an ER-resident mutant PLP1 containing an alanine-243 to valine (A243V) substitution, which induces severe PMD in human. By preventing mutant PLP1 translation through enhancing the phosphorylation of eukaryotic initiation factor 2 alpha, chloroquine ameliorated the ER stress induced by the mutant protein in HeLa cells. Chroloquine also attenuated ER stress in the primary oligodendrocytes obtained from myelin synthesis deficit (msd) mice, which carry the same PLP1 mutation. In the spinal cords of msd mice, chloroquine inhibited ER stress and upregulated the expression of marker genes of mature oligodendrocytes. Chloroquine-mediated attenuation of ER stress was observed in HeLa cells treated with tunicamycin, an N-glycosylation inhibitor, but not with thapsigargin, a sarco/ER Ca2+ATPase inhibitor, which confirms its efficacy against ER stress caused by nascent proteins. These findings indicate that chloroquine is an ER stress attenuator with potential use in treating PMD and possibly other ER stress-related diseases.

Aquaporin-4 autoimmunity in a child without optic neuritis and myelitis

Neuromyelitis optica (NMO) is an inflammatory demyelinating disease with a poor prognosis that is characterized by inflammatory optic neuritis and myelitis. Although it is commonly misdiagnosed as multiple sclerosis (MS), distinguishing NMO from MS is important, as therapeutic approaches approved for MS are ineffective in patients with NMO. The aquaporin-4 (AQP4) antibody is a pathogenic and diagnostic biomarker for NMO. We report an AQP4 antibody-positive 9-year-old female with intractable hiccups and nausea (IHN). Brain imaging revealed lesions in the brainstem, thalami, and hypothalamus. Nevertheless, she had no clinical or radiological signs referable to the optic nerve or spinal cord. We propose that in patients with characteristic IHN associated lesions involving the brainstem or hypothalamus, measurement of AQP4 antibody should be considered for selectivity of treatment, even if the patient has no optic nerve or spinal cord lesions.

High-dose phenobarbital with intermittent short-acting barbiturates for acute encephalitis with refractory, repetitive partial seizures.

Acute encephalitis with refractory, repetitive partial seizures (AERRPS) is characterized by repetitive seizures during the acute and chronic phases and has a poor neurological outcome. Burst‐suppression coma via continuous i.v. infusion of a short‐acting barbiturate is used to terminate refractory seizures, but the severe side‐effects of short‐acting barbiturates are problematic. We report on a 9‐year‐old boy with AERRPS who was effectively treated with very‐high‐dose phenobarbital (VHDPB) combined with intermittent short‐acting barbiturates. VHDPB side‐effects were mild, especially compared with those associated with continuous i.v. infusion of short‐acting barbiturates (dosage, 40–75 mg/kg/day; maximum blood level, 290 μg/mL). Using VHDPB as the main treatment, short‐acting barbiturates were used intermittently and in small amounts. This is the first report to show that VHDPB, combined with intermittent short‐acting barbiturates, can effectively treat AERRPS. After treatment, convulsions were suppressed and daily life continued, but intellectual impairment and high‐level dysfunction remained.

Extremely low-dose vigabatrin for West syndrome with tuberous sclerosis

Treatment of west syndrome in patients with tuberous sclerosis, the relevant effective period and doses of vigabatrin (VGB) to avoid serious side effects still needs further investigation. We report on a Japanese girl who showed good results with a very low dose of VGB. Tonic spasms appeared at 5 mo of age. Adrenocorticotropic hormone therapy resulted in incomplete seizure control. VGB at the lowest practical dose (30 mg/kg/d) showed complete control after 3 d. With reduction of the dose to 10 mg/kg/d, side effects such as hyperactivity, irritability, and sleep disturbances improved. She was seizure-free for the next 6 mo with an improved developmental quotient. Ophthalmological evaluation revealed no abnormality. The present case illustrates that low-dose VGB therapy (10 mg/kg/d) has fewer side effects and may bring prompt seizure control in west syndrome with tuberous sclerosis.

Periodic Eye Movements and Epileptic Spasms in West Syndrome

In addition to the typical infantile spasm symptoms, several other symptoms, such as eye movements, have been reported to be associated with infantile spasms, although the relationship between the typical spasms and these other events is not fully understood. Here we present a case with West syndrome. We observed the appearance of periodic eye movements followed by the onset of typical spasms and the appearance/disappearance of periodic eye movements during withdrawal/increases of vigabatrin. We believe that the case strongly supports the notion that periodic eye movements and typical spasms represent a spectrum of symptoms related to the same phenomenon of West syndrome.