Thalamic involvement determined using VSRAD advance on MRI and easy Z-score analysis of 99mTc-ECD-SPECT in Gerstmann-Sträussler-Scheinker syndrome with P102L mutation

Case report: A Chinese patient with spinocerebellar ataxia finally confirmed as Gerstmann-Sträussler-Scheinker syndrome with P102L mutation

Gerstmann-Sträussler-Scheinker syndrome (GSS) is a rare genetic prion disease caused by a mutation in the prion protein (PRNP) gene. It is typically characterized by progressive cerebellar ataxia and slowly progressive dementia. We present a case study of the GSS from China in which a 45-year-old male with a progressive gait and balance disorder developed cerebellar ataxia onset but was misdiagnosed as spinocerebellar ataxia (SCA) for 2 years. The patient's clinical, electrophysiological, and radiological data were retrospectively analyzed. Examination revealed ataxia, dysarthria, muscle weakness, areflexia in lower limbs, including a pyramidal sign, whereas cognitive decline was insignificant. His late mother had a similar unsteady gait. An electroencephalogram (EEG) showed normal findings, and 14-3-3 protein was negative. A brain MRI was performed for global brain atrophy and ventricular enlargement. Positron emission tomography-computed tomography (PET-CT) (18F-fluoro-2-deoxy-d-glucose, FDG) images showed mild to moderate decreased glucose metabolism in the left superior parietal lobe and left middle temporal lobe. According to genetic testing, his younger brother also had the P102L variant in the PRNP gene. This single case adds to the clinical and genetic phenotypes of GSS.

Prion Mutations in Republic of Republic of Korea, China, and Japan

Prion gene (PRNP) mutations are associated with diverse disease phenotypes, including familiar Creutzfeldt-Jakob Disease (CJD), Gerstmann-Sträussler-Scheinker disease (GSS), and fatal familial insomnia (FFI). Interestingly, PRNP mutations have been reported in patients diagnosed with Alzheimer's disease, dementia with Lewy bodies, Parkinson's disease, and frontotemporal dementia. In this review, we describe prion mutations in Asian countries, including Republic of Republic of Korea, China, and Japan. Clinical phenotypes and imaging data related to these mutations have also been introduced in detail. Several prion mutations are specific to Asians and have rarely been reported in countries outside Asia. For example, PRNP V180I and M232R, which are rare in other countries, are frequently detected in Republic of Korea and Japan. PRNP T188K is common in China, and E200K is significantly more common among Libyan Jews in Israel. The A117V mutation has not been detected in any Asian population, although it is commonly reported among European GSS patients. In addition, V210I or octapeptide insertion is common among European CJD patients, but relatively rare among Asian patients. The reason for these differences may be geographical or ethical isolation. In terms of clinical phenotypes, V180I, P102L, and E200K present diverse clinical symptoms with disease duration, which could be due to other genetic and environmental influences. For example, rs189305274 in the ACO1 gene may be associated with neuroprotective effects in cases of V180I mutation, leading to longer disease survival. Additional neuroprotective variants may be possible in cases featuring the E200K mutation, such as KLKB1, KARS, NRXN2, LAMA3, or CYP4X1. E219K has been suggested to modify the disease course in cases featuring the P102L mutation, as it may result in the absence of prion protein-positive plaques in tissue stained with Congo red. However, these studies analyzed only a few patients and may be too preliminary. The findings need to be verified in studies with larger sample sizes or in other populations. It would be interesting to probe additional genetic factors that cause disease progression or act as neuroprotective factors. Further studies are needed on genetic modifiers working with prions and alterations from mutations.

Development of a quantitative statistical analysis system for double inversion recovery (DIR) MRI: A preliminary clinical study

BACKGROUND

Gray matter (GM) imaging is important in the investigation of many neurological diseases, including schizophrenia, multiple sclerosis, stroke, Alzheimer's disease, tuberous sclerosis, and epilepsy, which are all associated with changes in cortical GM.

OBJECTIVE

The aim of this study was to develop a quantitative statistical analysis system for double inversion recovery (DIR) MRI and to evaluate the new system using preliminary clinical data.

METHODS

The study population comprised of 10 healthy volunteers and six patients with or without brain degeneration. A quantitative statistical analysis system for DIR images was developed using the following steps: 1) brain spatial normalization, 2) mean and standard deviation (SD) map creation, and 3) Z-score map creation. To evaluate the new voxel-based morphometry system, Z-scores of lesions in patients with brain degeneration were measured and then compared with Z-scores of normal regions.

RESULTS

All DIR images were adequately spatially normalized to Montreal Neurological Institute MNI coordinate. Lesions in each patient were indicated by high Z-score values on a Z-score map, which were significantly higher than Z-scores of normal regions (p< 0.05).

CONCLUSIONS

In this study, we developed a quantitative statistical analysis system for DIR MRI. Using our system, clinicians might accurately diagnose early brain degeneration.

Clinical Variability in P102L Gerstmann-Sträussler-Scheinker Syndrome

Gerstmann-Sträussler-Scheinker syndrome (GSS) with the P102L mutation is a rare genetic prion disease caused by a pathogenic mutation at codon 102 in the prion protein gene. Cluster analysis encompassing data from 7 Czech patients and 87 published cases suggests the existence of 4 clinical phenotypes (typical GSS, GSS with areflexia and paresthesia, pure dementia GSS, and Creutzfeldt-Jakob disease-like GSS); GSS may be more common than previously estimated. In making a clinical diagnosis or progression estimates of GSS, magnetic resonance imaging and real-time quaking-induced conversion may be helpful, but the results should be evaluated with respect to the overall clinical context. ANN NEUROL 2019;86:643-652.

Gerstmann-Sträussler-Scheinker disease: A case report

BACKGROUND

Gerstmann-Sträussler-Scheinker (GSS) disease is an inherited prion disease that is clinically characterized by the early onset of progressive cerebellar ataxia. The incidence of GSS is extremely low and it is particularly rare in China. Therefore, clinicians may easily confuse this disease with other diseases that also cause ataxia, resulting in its under-diagnosis or misdiagnosis.

CASE SUMMARY

Here, we report the first case of genetically diagnosed GSS disease in Northeast China. The patient exhibited typical ataxia and dysarthria 2.5 years after symptom onset. However, magnetic resonance imaging of the brain and spinal cord revealed a normal anatomy. Screening results for the spinocerebellar ataxia gene were also negative. We thus proposed to expand the scope of genetic screening to include over 200 mutations that can cause ataxia. A final diagnosis of GSS was presented and the patient was followed for more than 3.5 years, during which we noted imaging abnormalities. The patient gradually exhibited decorticate posturing and convulsions. We recommended administration of oral sodium valproate, which resolved the convulsions.

CONCLUSION

Patients with inherited ataxia should be considered for a diagnosis of GSS via genetic testing at an early disease stage.

Voxel-based Specific Regional Analysis System for Alzheimer's Disease (VSRAD) on 3-tesla Normal Database: Diagnostic Accuracy in Two Independent Cohorts with Early Alzheimer's Disease

Voxel-based specific regional analysis system for Alzheimer’s disease (VSRAD) software is widely used in clinical practice in Alzheimer’s disease (AD). The existing VSRAD is based on the normal database with 1.5-tesla MRI scans (VSRAD-1.5T), and its utility for patients have undergone 3-tesla MRI is still controversial. We recruited 19 patients with early AD and 28 healthy controls who had undergone 3-tesla MRI scans at our institute (Cohort 1). We also used the 3-tesla MRI data of 30 patients with early AD and 13 healthy controls from the Japanese Alzheimer’s Disease Neuroimaging Initiative (Cohort 2). We also created a new VSRAD based on 65 normal subjects’ 3-tesla MRI scans (VSRAD-3T), and compared the detectability of AD between VSRAD-1.5T and VSRAD-3T, using receiver operating characteristic curve and area under the curve (AUC) analyses. As a result, there were no significant differences in the detectability of AD between VSRAD-3T and VSRAD-1.5T, except for the whole white matter atrophy score, which showed significantly better AUC in VSRAD-3T than in VSRAD-1.5T in both Cohort 1 (p=0.04) and 2 (p<0.01). Generally, there were better diagnostic values in Cohort 2 than in Cohort 1. The optimal cutoff values varied but were generally lower than in the previously published data. In conclusion, for patients with 3-tesla MRI, the detectability of early AD by the existing VSRAD was not different from that by the new VSRAD based on 3-tesla database. We should exercise caution when using the existing VSRAD for 3-tesla white matter analyses or for setting cutoff values.