Novel De Novo KCND3 Mutation in a Japanese Patient with Intellectual Disability, Cerebellar Ataxia, Myoclonus, and Dystonia.

Spinocerebellar ataxia 19/22 (SCA19/22) is a rare type of autosomal dominant SCA that was previously described in 11 families. We report the case of a 30-year-old Japanese man presenting with intellectual disability, early onset cerebellar ataxia, myoclonus, and dystonia without a family history. MRI showed cerebellar atrophy, and electroencephalograms showed paroxysmal sharp waves during hyperventilation and photic stimulation. Trio whole-exome sequencing analysis of DNA samples from the patient and his parents revealed a de novo novel missense mutation (c.1150G>A, p.G384S) in KCND3, the causative gene of SCA19/22, substituting for evolutionally conserved glycine. The mutation was predicted to be functionally deleterious by bioinformatic analysis. Although pure cerebellar ataxia is the most common clinical feature in SCA19/22 families, extracerebellar symptoms including intellectual disability and myoclonus are reported in a limited number of families, suggesting a genotype-phenotype correlation for particular mutations. Although autosomal recessive diseases are more common in patients with early onset sporadic cerebellar ataxia, the present study emphasizes that such a possibility of de novo mutation should be considered.

Neurophysiological differentiation of upper motor neuron damage in neurodegenerative disorders.

Objective: Using transcranial magnetic stimulation (TMS) to delineate upper motor neuron (UMN) signs of two neurodegenerative disorders: amyotrophic lateral sclerosis (ALS) and multiple system atrophy (MSA). Methods: Medical records including clinical signs for UMN damage and TMS results were reviewed retrospectively. The UMN signs were classified into none, mild, and severe based on neurological examination of various reflexes. Then TMS-elicited motor evoked potentials (MEPs) were recorded from a hand and a leg muscle to calculate the central motor conduction time (CMCT), which represents fast, mono-synaptic conduction along the corticospinal tract. Relations between the UMN signs and CMCT were analysed for the two diseases. Results: Prevalence and severity of the UMN signs for ALS and MSA were comparable for both upper and lower limbs. However, abnormality in CMCT was found more frequently in ALS: CMCT abnormalities were found in upper limbs for 44% in ALS patients but only for 7% in MSA patients; CMCT abnormalities in lower limbs were 55% in ALS and 20% in MSA. Some ALS patients showed abnormal CMCT in limbs without UMN signs, which was not true for most MSA patients. Conclusions: The abnormalities of CMCT were different in ALS and MSA, even for those who clinically had similar UMN signs. Sometimes, CMCT can reveal UMN damage in the absence of clinical UMN signs. Differences presumably derive from selective degeneration of different fibres in the motor descending pathways. Longitudinal studies must be conducted to accumulate neuroimaging and pathological findings. Significance: CMCT can be useful to differentiate ALS and MSA.

Rituximab improves not only back stiffness but also "stiff eyes" in stiff person syndrome: Implications for immune-mediated treatment.

OBJECTIVE: Stiff person syndrome (SPS) is usually characterized by truncal muscle rigidity and episodic painful spasms, but it sometimes appears with ocular symptoms called "stiff eyes". We recorded saccade movements in an SPS patient manifesting with "stiff eyes" conditions with slow saccade velocity and evaluated the effect of immunotherapy including rituximab on saccade parameters. METHODS: We repeatedly conducted saccade eye recordings using video-based eye tracking system on a 42-year-old male SPS patient with slow saccade. The velocity and onset latency of visual guided saccades (VGS) were measured at each recording. Because VGS velocity is affected by saccade amplitude, estimated peak velocity (Vmax) was also calculated by taking the relationship between the velocity and the amplitude of saccade into account. RESULTS: The mean VGS velocity improved significantly after two courses of rituximab administration compared with its lowest value. The estimated Vmax decreased as the clinical manifestations worsened, but it increased after rituximab administration. Other neurological symptoms in this patient such as muscle rigidity and gait instability also improved after the treatment. CONCLUSION: Slow saccade in a "stiff eyes" patient improved after rituximab administration. Our study also indicated that the saccade eye recording is useful for evaluating the clinical condition of SPS when it is complicated with ocular symptoms.

Multinodular and vacuolating neuronal tumor (MVNT): A presumably incidental and asymptomatic case in an intractable epilepsy patient.

INTRODUCTION: Multinodular and vacuolating neuronal tumor (MVNT) had been initially described as an epilepsy-related brain tumor, but recent studies demonstrated it could be found incidentally in non-epilepsy patients. CASE REPORT: A 33-year-old woman with intractable post-encephalitis epilepsy presented a cluster of multinodular T2 hyperintensity in the left temporal lobe, which was very similar to the characteristics of MVNT. Long-term video electroencephalogram demonstrated that the habitual seizures were originated from bilateral temporal area and the interictal epileptic discharges were seen multifocally, although the lesions with MVNT appearance were localized in the left temporal lobe. It was presumed that the epilepsy in this patient was due to encephalitis in the past, and the link between the lesions and the epilepsy in this patient seemed weak. CONCLUSION: Although MVNT had been considered as an epilepsy-related brain tumor, we suggest it is not necessarily preferable to perform surgical resection of MVNT even on patients with epilepsy, unless epileptic foci are highly related to MVNT.

Optic neuropathy and decorticate-like posture as presenting symptoms of Bickerstaff's brainstem encephalitis: A case report and literature review.

A 72-year-old woman with a 10-day history of bilateral visual impairment after respiratory tract infection showed decorticate-like posture and progressive deterioration of consciousness leading to coma. Ophthalmoplegia was also noted and anti-GQ1b antibodies were positive, consistent with Bickerstaff's brainstem encephalitis. After intravenous immunoglobulin and steroid pulse therapy, her consciousness gradually improved. However, severe visual impairment at the level of hand motion was noticed, which gradually normalized after second steroid pulse therapy. Atypical findings including optic neuropathy and decorticate-like posture can be seen in patients with Bickerstaff's brainstem encephalitis, and early diagnosis is essential for adequate management.

Improved 123I-Ioflupane Binding After Immunotherapy in Anti-NAE Antibody-Positive Hashimoto Encephalopathy That Clinically Mimicked Multiple System Atrophy.

We describe an 84-year-old man with anti-NH2-terminal of α-enolase antibody-positive Hashimoto encephalopathy that clinically mimicked multiple system atrophy who underwent investigation by dopamine transporter SPECT before and after immunotherapy. Before treatment, dopamine transporter SPECT showed reduced striatal I-ioflupane binding, with a mean specific binding ratio of 2.42, even though he had no apparent parkinsonism. After immunotherapy, mean specific binding ratio was improved to 3.22. Dopamine transporter SPECT was useful in this case to detect subclinical striatal dysfunction, and evaluation both before and after immunotherapy helped to distinguish between neurodegenerative disease and neuroimmunological disorder.