Disrupted Brain Network Topology in Drug-naïve Essential Tremor Patients with and Without Depression : A Resting State Functional Magnetic Resonance Imaging Study.

PURPOSE: This study was carried out to investigate brain functional connectome and its potential relationships with the disease severity and emotion function in patients with essential tremor with and without depressive symptoms by using resting-state functional magnetic resonance imaging and graph theory approaches. METHODS: In this study 33 essential tremor patients with depression, 45 essential tremor patients without depression and 79 age and gender-matched healthy controls were recruited to undergo a 3.0­T imaging scan. The whole brain functional connectome was constructed by thresholding the partial correlation matrices of 116 brain regions, and the topologic properties were analyzed by using graph theory approaches and network-based statistic approaches. Nonparametric permutation test was also used for group comparisons of topological metrics. Correlation analyses between topographic features and the clinical characteristics were performed. RESULTS: The functional connectome in both essential tremor patients with and without depression showed abnormalities at the global level (decrease in clustering coefficient, global efficiency, and local efficiency but increase in characteristic path length) and at the nodal level (decrease nodal centralities in the cerebellum, motor cortex, prefrontal-limbic regions, default mode network) (p < 0.05, false discovery rate corrected). Moreover, essential tremor patients with depression showed higher node efficiency in superior frontal gyrus and posterior cingulate gyrus compared to essential tremor without depression. CONCLUSION: Our results may provide insights into the underlying pathophysiology of essential tremor patients with and without depression and aid the development of some potential biomarkers of the depressive symptoms in patients with essential tremor.

A compound heterozygous PINK1-associated juvenile Parkinson's disease with pregnancy in Chinese.

BACKGROUND: PINK1 mutations are the second most common cause of recessive, early-onset Parkinson's disease (EOPD), of which 15% are cases of juvenile PD. PD is a progressive neurological disease that primarily affects middle-aged and older people. Thus PD patients experiencing pregnancy is uncommon, especially in patients with juvenile PD caused by PINK1 mutations. We are first to report a woman from a Chinese family diagnosed with sporadic juvenile PD and treated with levodopa/benserazide throughout pregnancy. METHODS: Whole exome sequencing was performed on this patient, and pedigree verification was performed on her parents. This patient received levodopa/benserazide treatment with regular outpatient follow-up exams. RESULTS: Whole exome sequencing and Sanger sequencing identified a heterozygous nonsense mutation (c.1474C > T, p.R492X) and a splicing mutation (c.1488 + 1G > A) that were in exon 7 of the PINK1 gene, co-segregating with the PD phenotype and exhibiting an autosomal recessive pattern. With regular outpatient follow-up exams, this patient delivered a healthy boy without complications. Her PD symptoms were stable with the levodopa/benserazide treatment throughout her pregnancy except in the postpartum period. CONCLUSION: Our findings further demonstrated the safety of levodopa with dopa-decarboxylase treatment in PINK1-associated juvenile PD during pregnancy.

Altered spontaneous brain activity in essential tremor with and without resting tremor: a resting-state fMRI study.

OBJECTIVES: Essential tremor with resting tremor (rET) often exhibits severer clinical features and more extensive functional impairment than essential tremor without resting tremor (ETwr). However, the pathophysiology of rET is still unclear. This study aims to use resting-state functional magnetic resonance imaging (rs-fMRI) to explore the alterations of brain activity between the drug-naïve patients of rET and ETwr. METHODS: We recruited 19 patients with rET, 31 patients with ETwr and 25 healthy controls (HCs) to undergo a 3.0-T rs-fMRI examination. The differences of regional brain spontaneous activity between the rET, ETwr and HCs, as well as between total ET (rET + ETwr) and HCs were measured by amplitude of low-frequency fluctuation (ALFF) and fractional ALFF (fALFF). The relationships between the altered brain measurements and the clinical scores were analyzed. RESULTS: Compared with HCs, both ET subgroups showed significantly decreased ALFF or fALFF values in the basal ganglia, inferior orbitofrontal gyrus and insula. The rET group specifically showed decreased ALFF values in the hippocampus and motor cortices, while the ETwr group specifically evidenced increased ALFF and fALFF values in the cerebellum. DISCUSSION: Regional spontaneous activity in rET and ETwr share common changes and have differences, which may suggest that the functional activities in the limbic system and cerebellum are different between the two subtypes. Improved insights into rET and ETwr subtypes and the different brain spontaneous activity will be valuable for improving our understanding of the pathophysiology of the disease.

Patterns of intrinsic brain activity in essential tremor with resting tremor and tremor-dominant Parkinson's disease.

The clinical pictures of essential tremor (ET) with resting tremor (rET) and tremor-dominant Parkinson's disease (tPD) are often quite mimic at the early stage, current approaches to the diagnosis and treatment therefore remain challenging. The regional homogeneity (ReHo) method under resting-state functional magnetic resonance imaging (rs-fMRI) would help exhibit the patterns in neural activity, which further contribute to differentiate these disorders and explore the relationship between symptoms and regional functional abnormalities. Sixty-eight Chinese participants were recruited, including 19 rET patients, 24 tPD patients and 25 age- and gender-matched healthy controls (HCs). All participants underwent clinical assessment and rs-fMRI with a ReHo method to investigate the alterations of neural activity, and the correlation between them. Differences were compared by two-sample t-test (corrected with AlphaSim, p < 0.05). Compared with HCs, patients' groups both displayed decreased ReHo in the default mode network (DMN), bilateral putamen and bilateral cerebellum. While tPD patients specifically exihibited decreased ReHo in the bilateral supplementary motor area (SMA) and precentral gyrus (M1). The correlation analysis revealed that ReHo in the bilateral putamen, right SMA and left cerebellum_crus I were negatively correlated with the UPDRS-III score, respectively, in tPD group. Our results indicated the rET patients may share part of the pathophysiological mechanism of tPD patients. In addition, we found disorder-specific involvement of the SMA and M1 in tPD. Such a distinction may lend itself to use as a potential biomarker for differentiating between these two diseases.

Association of three candidate genetic variants in ACMSD/TMEM163, GPNMB and BCKDK /STX1B with sporadic Parkinson's disease in Han Chinese.

Large-scale meta-analyses of genome-wide association studies have identified that polymorphisms ACMSD/TMEM163 rs6430538, GPNMB rs199347 and BCKDK /STX1B rs14235 to be the risk loci for Parkinson's disease (PD) in a Caucasian population. However, the role of these three polymorphisms in a Han Chinese population from mainland China still remains to be clarified. We conducted a large sample study to examine genetic associations of rs6430538, rs199347 and rs14235 with PD in a Han Chinese population of 989 sporadic PD patients and 1058 healthy controls. All subjects were genotyped for these loci using the Sequenom iPLEX Assay. In addition, we conducted further stratified analysis according to age at onset and compared the clinical characteristics between minor allele carriers and non-carriers for each locus. However, no significant differences were found in genotype and allele frequency distribution between PD patients and controls for the three loci, even after being stratified by age at onset. Moreover, we demonstrated that minor allele carriers cannot be distinguished from non-carriers based on their clinical features. Our study is the first to demonstrate that ACMSD/TMEM163 rs6430538, GPNMB rs199347 and BCKDK /STX1B rs14235 do not confer a significant risk for sporadic PD in mainland China. Therefore, more replication studies in additional Chinese population and other cohorts and functional studies are warranted to further clarify the role of the three loci in PD susceptibility.