[A case of anti-SRP antibody-positive immune-mediated necrotizing myopathy triggered by human parvovirus B19 infection].

We have reported a case of a 44-year-old woman with anti-signal recognition particle (SRP) antibody-positive immune-mediated necrotizing myopathy triggered by human parvovirus B19 (PVB19) infection. She was admitted to the hospital because of lower leg edema and muscle weakness after erythema infectiosum. Magnetic resonance imaging of the lower extremities revealed high signals in the proximal muscles and subcutaneous edema on STIR. Muscle biopsy showed myofiber regenerative changes and variation in fiber size. A myositis-specific autoantibody profile indicated a positive result for anti-SRP antibodies. We diagnosed the patient with immune-mediated necrotizing myopathy (IMNM). Muscle strength and subcutaneous edema improved gradually in 3 months following immunotherapy. This is the first case report of an IMNM associated with PVB19 infection.

Identification and functional characterization of novel mutations including frameshift mutation in exon 4 of CSF1R in patients with adult-onset leukoencephalopathy with axonal spheroids and pigmented glia.

OBJECTIVE: Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is caused by mutations in CSF1R. Pathogenic mutations in exons 12-22 including coding sequence of the tyrosine kinase domain (TKD) of CSF1R were previously identified. We aimed to identify CSF1R mutations in patients who were clinically suspected of having ALSP and to determine the pathogenicity of novel CSF1R variants. METHODS: Sixty-one patients who fulfilled the diagnostic criteria of ALSP were included in this study. Genetic analysis of CSF1R was performed for all the coding exons. The haploinsufficiency of CSF1R was examined for frameshift mutations by RT-PCR. Ligand-dependent autophosphorylation of CSF1R was examined in cells expressing CSF1R mutants. RESULTS: We identified ten variants in CSF1R including two novel frameshift, five novel missense, and two known missense mutations as well as one known missense variant. Eight mutations were located in TKD. One frameshift mutation (p.Pro104LeufsTer8) and one missense variant (p.His362Arg) were located in the extracellular domain. RT-PCR analysis revealed that the frameshift mutation of p.Pro104LeufsTer8 caused nonsense-mediated mRNA decay. Functional assay revealed that none of the mutations within TKD showed autophosphorylation of CSF1R. The p.His362Arg variant located in the extracellular domain showed comparable autophosphorylation of CSF1R to the wild type, suggesting that this variant is not likely pathogenic. CONCLUSIONS: The detection of the CSF1R mutation outside of the region-encoding TKD may extend the genetic spectrum of ALSP with CSF1R mutations. Mutational analysis of all the coding exons of CSF1R should be considered for patients clinically suspected of having ALSP.

[A case of short-lasting unilateral neuralgiform headache with conjunctival injection and tearing triggered by mumps meningitis in a patient with recurrent primary stabbing headache].

A 32-year-old man with a 16-year history of recurrent primary stabbing headache was admitted to our hospital, owing to mumps meningitis. On day 2 of admission, he began experiencing episodes of unbearable intermittent stabbing pain, each lasting few seconds, with conjunctival injection and tearing, on the temporal side of the left orbit. We suspected trigeminal autonomic cephalgias, and administered non-steroidal anti-inflammatory drugs (NSAIDs), oxygen, and sumatriptan; however, the pain episodes persisted. Subsequently, after the start of intravenous lidocaine administration, the pain episodes stopped. We diagnosed a short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT), triggered by mumps meningitis. This is a valuable case report, involving a patient with a history of primary stabbing headache who was diagnosed with SUNCT triggered by mumps meningitis.

Distinct Incidence of Takotsubo Syndrome Between Amyotrophic Lateral Sclerosis and Synucleinopathies: A Cohort Study.

Takotsubo syndrome (TTS) is an acute cardiac syndrome characterized by regional left ventricular dysfunction with a peculiar circumferential pattern, which typically results in apical ballooning. Evidence indicates a pivotal role of catecholamines in TTS, and researchers have discussed multiple hypotheses on the etiology, including multivessel coronary spasm, myocardial stunning, excessive transient ventricular afterload, and cardiac sympathetic overactivity with local noradrenaline spillover. Although central nervous system disorders, such as stroke and epilepsy, are known to trigger TTS, the incidence and clinical features of TTS in neurodegenerative disorders are poorly understood. Here, we retrospectively examined TTS cases in a single-center cohort composed of 250 patients with amyotrophic lateral sclerosis (ALS) and 870 patients with synucleinopathies [582 patients with Parkinson's disease (PD), 125 patients with dementia with Lewy bodies (DLB), and 163 patients with multiple system atrophy (MSA)] and identified 4 (1.6%, including 2 women) cases with ALS and no cases with synucleinopathies. Two ALS patients underwent autopsy and the pathological findings were compatible with the chronological changes identified in catecholamine-induced cardiomyopathy. A literature review identified 16 TTS cases with ALS, 1 case each with PD and DLB, and no cases with MSA. When current and previous TTS cases with ALS were concatenated: 55% (11/20) were female; 35% (7/20) had a bulbar-onset and 45% (9/20) had a limb-onset; the mean age of TTS onset was 63.3 ± 9.0 years and the mean interval time from ALS onset to TTS development was 4.9 ± 3.0 years; no (0/16) patients developed TTS within 12 months after ALS onset; 50% (10/20) underwent artificial ventilations; the mortality was 17% (3/18); and most cases had precipitating factors, and TTS development was associated with gastrostomy, tracheostomy, or infections in 45% (9/20) of the patients. This study demonstrated that ALS is a considerable predisposing factor of TTS and that synucleinopathies rarely cause TTS. The distinct TTS incidence between ALS and synucleinopathies may be due to cardiac sympathetic overactivity in ALS and may also be affected by cardiac sympathetic denervation in synucleinopathies. Moreover, the etiology of TTS in ALS may be reasonably explained by the two-hit theory.

Memory B cell resurgence requires repeated rituximab in myasthenia gravis.

The immunologic effects of rituximab (RTX) in myasthenia gravis (MG) remain to be explored. We aimed to clarify immunologic reactions and their association with response to RTX in MG. Regulatory T cell and B cell profiles of MG patients were monitored. Two patients presenting with generalized MG with anti-acetylcholine receptor antibodies were treated with RTX. The treatment led to sustained clinical improvement, discontinuation of intravenous immunoglobulin or plasma exchange, and reduction of prednisolone and other drugs. One patient was in remission for more than one year, whereas the other patient exhibited deterioration of symptoms within one year. Disease activity was associated with the repopulation of IgD-CD27- and IgD-CD27+ memory B cells. Clinicians should be aware of the possibility that MG ranges in the duration of B cell depletion and additional RTX should be prescribed upon resurgence of memory B cells.

[A case of Parkinson's disease following restless genial sensation].

A 62-year-old woman experienced uncomfortable genial sensation in 2010. Her uncomfortable sensation was exacerbated during rest at night and improved by walking. She exhibited short-stepped gait with postural disturbance and was diagnosed as suffering from Parkinson's disease (PD) in 2013. Administration of clonazepam and pramipexisole improved her uncomfortable genial sensation. In persistent genital arousal disorder (PGAD)/restless genial syndrome (RGS), abnormal genital sensation occurred without sexual desire, which was relieved by clonazepam administration. PGAD/RGS often coexists with restless legs syndrome (RLS). PGAD/RGS and RLS share common characteristics. This is the first case report of PD following PGAD/RGS, suggesting similar underlying mechanisms between PGAD/RGS and RLS associated with PD.