"Missing-piece" sign with dural arteriovenous fistula at craniocervical junction: A case report.

OBJECTIVES: Spinal dural arteriovenous fistula (sDAVF) is a rare and often underdiagnosed spinal disease. Early diagnosis is required because the deficits are reversible and delays in treatment cause permanent morbidity. Although the abnormal vascular flow void is a critical radiographic feature of sDAVF, they are not always present. A characteristic enhancement pattern of sDAVF has been recently reported as the "missing-piece" sign which can lead to the early and correct diagnosis. METHODS: We presented imaging findings, treatment decisions, and the outcome of a rare case of sDAVF, in which the "missing-piece" sign appeared atypical. RESULTS: A 60-year-old woman developed numbness and weakness in her extremities. Spinal MRI revealed longitudinal hyperintensity in the T2-weighted image, extending from the thoracic level to medulla oblongata. At first, myelopathy with inflammation or tumor was suspected because of the lack of flow voids and vascular abnormalities in CT-angiography and MR-DSA. However, we administered intravenous methylprednisolone and her symptom got worse with the appearance of the "missing-piece" sign. Then, we successfully diagnosed sDAVF by angiography. The "missing-piece" sign was considered to derive from inconsistency of the intrinsic venous system of spinal cord, with the abrupt segments without enhancement. The same etiology was considered in our case. CONCLUSIONS: Detecting the "missing-piece" sign can lead to the correct diagnosis of sDAVF, even if the sign appeared atypical.

Two Medullary Hemorrhage Cases Complicated by Respiratory Distress in the Early Phase.

Medullary hemorrhage is quite rare among brain stem hemorrhage cases, thus the clinical course remains unclear. In the medulla oblongata, respiratory centers are located and previous reports indicate that medullary lesions have possible relationship with acute respiratory distress syndrome. This kind of respiratory failure is commonly caused by neurogenic pulmonary edema (NPE), which is defined as noncardiac noninfectious acute respiratory distress syndrome with changes in intracranial condition including cerebrovascular events. However, to date, very few reports have described cases with medullary hemorrhage accompanied by NPE. We experienced 2 patients with medullary hemorrhages. A 65-year-old man presented with sudden onset of headache, whose head computed tomography showed right medullary hemorrhage. Another 76-year-old woman was transferred because of sudden limb weakness and diagnosed with left medullary hemorrhage. Digital subtraction angiography showed the presence of arteriovenous fistula in the medulla oblongata and drainer veins in the second case. Both cases were complicated by acute pulmonary edema in the early phase, suggesting the possible association of the medullary hemorrhage with NPE.

[Aging-related frailty and sarcopenia. Frailty and sarcopenia in the centenarians.]

The aging of society is coming up in Japan and it is one of the most important issues for us to prevent or reduce frailty and sarcopenia, two major causes of disability in older adults. In centenarians, the frailty and sarcopenia could be key factors to determine the prognosis. Maintaining both physical and cognitive functions influences the improvement of QOL and the independence of ADL. Recent studies have demonstrated pathogenic roles of age-related inflammatory activation(inflammaging), and some of circulation biomarkers for frailty are developed. It is important to prevent frailty and sarcopenia by caring a lifestyle from the earlier ages in life, preparing for the aging society with healthy status.

Association of polydoctoring and mortality among very old persons with multimorbidity: a prospective cohort study in Japan.

BACKGROUND: Polydoctoring is a crucial aspect of care fragmentation among patients with multimorbidity, but its impact on health outcomes remains unclear. AIM: To determine the effects of polydoctoring, as measured by the Regularly Visited Facility (RVF) indicator, on patient outcomes among older individuals with multimorbidity. DESIGN & SETTING: Data from the ongoing prospective cohort study, Kawasaki Aging and Wellbeing Project (KAWP), was utilized in this study. Among the 1,026 KAWP participants aged 85-89 years, those with two or more chronic conditions were enrolled in this study. METHOD: Care fragmentation or polydoctoring, was evaluated using the RVF, a new indicator that measures the number of medical facilities consistently involved in a patient's care. Based on RVF, mortality was analysed using the Cox-hazards model, with adjustments for age, sex, frailty, and number of comorbidities. RESULTS: A significant reduction in mortality rates was observed in participants with an RVF of ≥3 and 2-4 comorbidities (hazard ratio [HR] 0.46, 95% confidence interval [CI]: 0.18-0.99). However, no significant difference in mortality based on RVF was observed for those with ≥5 comorbidities. Notably, individuals with ≥5 comorbidities and an RVF of 0 had a significantly higher HR for death (HR 2.68, 95% CI 1.05-6.84). CONCLUSIONS: In older patients with multimorbidity, polydoctoring reduces mortality in patients with ≤4 coexisting conditions, but it does not significantly impact mortality in those with ≥5 conditions. These findings provide insights for healthcare decision-making in managing older patients with multimorbidity.

Measurement of polydoctoring as a crucial component of fragmentation of care among patients with multimorbidity: Cross-sectional study in Japan.

Background: Care fragmentation, characterized by the uncoordinated involvement of multiple healthcare providers, leads to inefficient and ineffective healthcare, posing a significant challenge in managing patients with multimorbidity. In this context, "polydoctoring," where patients see multiple specialists, emerges as a crucial aspect of care fragmentation. This study seeks to develop an indicator to assess polydoctoring, which can subsequently enhance the management of multimorbidity. Methods: Baseline survey data from the Kawasaki Aging and Wellbeing Project (KAWP) involving independent community-dwelling older adults aged 85-89 were utilized in this cross-sectional study. Polydoctoring measure was defined as the number of regularly visited facilities (RVFs). The association of RVF with the Fragmentation of Care Index (FCI) and the outcome measures of polypharmacy and ambulatory care costs were examined as indicators of care fragmentation. Results: The analysis comprised 968 participants, with an average of 4.70 comorbid chronic conditions; 65.3% of the participants had two or more RVFs, indicating polydoctoring. A significant correlation between RVF and FCI was observed. Modified Poisson regression analyses revealed associations between higher RVF and increased prevalence ratio of polypharmacy. Likewise, a higher RVF was associated with higher outpatient medical costs. Conclusions: RVF was significantly correlated with FCI, polypharmacy, and higher outpatient medical costs. Unlike complex indices, RVF is simple and intuitively comprehensible. Further research is needed to evaluate the impact of care fragmentation on patient outcomes, considering factors such as RVF thresholds, patient multimorbidity, and social support. Understanding the influence of polydoctoring can enhance care quality and efficiency for patients with multimorbidity.

Status and physiological significance of circulating adiponectin in the very old and centenarians: an observational study.

Background: High levels of circulating adiponectin are associated with increased insulin sensitivity, low prevalence of diabetes, and low body mass index (BMI); however, high levels of circulating adiponectin are also associated with increased mortality in the 60-70 age group. In this study, we aimed to clarify factors associated with circulating high-molecular-weight (cHMW) adiponectin levels and their association with mortality in the very old (85-89 years of age) and centenarians. Methods: The study included 812 (women: 84.4%) for centenarians and 1498 (women: 51.7%) for the very old. The genomic DNA sequence data were obtained by whole-genome sequencing or DNA microarray-imputation methods. Least Absolute Shrinkage and Selection Operator (LASSO) and multivariate regression analyses were used to evaluate cHMW adiponectin characteristics and associated factors. All-cause mortality was analyzed in three quantile groups of cHMW adiponectin levels using Cox regression. Results: The cHMW adiponectin levels were increased significantly beyond 100 years of age, were negatively associated with diabetes prevalence, and were associated with SNVs in CDH13 (p=2.21 × 10-22) and ADIPOQ (p=5.72 × 10-7). Multivariate regression analysis revealed that genetic variants, BMI, and high-density lipoprotein cholesterol (HDLC) were the main factors associated with cHMW adiponectin levels in the very old, whereas the BMI showed no association in centenarians. The hazard ratios for all-cause mortality in the intermediate and high cHMW adiponectin groups in very old men were significantly higher rather than those for all-cause mortality in the low-level cHMW adiponectin group, even after adjustment with BMI. In contrast, the hazard ratios for all-cause mortality were significantly higher for high cHMW adiponectin groups in very old women, but were not significant after adjustment with BMI. Conclusions: cHMW adiponectin levels increased with age until centenarians, and the contribution of known major factors associated with cHMW adiponectin levels, including BMI and HDLC, varies with age, suggesting that its physiological significance also varies with age in the oldest old. Funding: This study was supported by grants from the Ministry of Health, Welfare, and Labour for the Scientific Research Projects for Longevity; a Grant-in-Aid for Scientific Research (No 21590775, 24590898, 15KT0009, 18H03055, 20K20409, 20K07792, 23H03337) from the Japan Society for the Promotion of Science; Keio University Global Research Institute (KGRI), Kanagawa Institute of Industrial Science and Technology (KISTEC), Japan Science and Technology Agency (JST) Research Complex Program "Tonomachi Research Complex" Wellbeing Research Campus: Creating new values through technological and social innovation (JP15667051), the Program for an Integrated Database of Clinical and Genomic Information from the Japan Agency for Medical Research and Development (No. 16kk0205009h001, 17jm0210051h0001, 19dk0207045h0001); the medical-welfare-food-agriculture collaborative consortium project from the Japan Ministry of Agriculture, Forestry, and Fisheries; and the Biobank Japan Program from the Ministry of Education, Culture, Sports, and Technology.

Impact of Amyloid and Tau PET on Changes in Diagnosis and Patient Management.

BACKGROUND AND OBJECTIVES: Previous studies have evaluated the diagnostic effect of amyloid PET in selected research cohorts. However, these studies did not assess the clinical impact of the combination of amyloid and tau PETs. Our objective was to evaluate the association of the combination of 2 PETs with changes in diagnosis, treatment, and management in a memory clinic cohort. METHODS: All participants underwent amyloid [18F]florbetaben PET and tau PET using [18F]PI-2620 or [18F]Florzolotau, which are potentially useful for the diagnosis of non-Alzheimer disease (AD) tauopathies. Dementia specialists determined a pre- and post-PET diagnosis that existed in both a clinical syndrome (cognitive normal [CN], mild cognitive impairment [MCI], and dementia) and suspected etiology, with a confidence level. In addition, the dementia specialists determined patient treatment in terms of ancillary investigations and management. RESULTS: Among 126 registered participants, 84.9% completed the study procedures and were included in the analysis (CN [n = 40], MCI [n = 25], AD [n = 20], and non-AD dementia [n = 22]). The etiologic diagnosis changed in 25.0% in the CN, 68.0% in the MCI, and 23.8% with dementia. Overall changes in management between pre- and post-PET occurred in 5.0% of CN, 52.0% of MCI, and 38.1% of dementia. Logistic regression analysis revealed that tau PET has stronger associations with change management than amyloid PET in all participants and dementia groups. DISCUSSION: The combination of amyloid and tau PETs was associated with changes in management and diagnosis of MCI and dementia, and the second-generation tau PET has a strong impact on the changes in diagnosis and management in memory clinics. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that the combination of amyloid and tau PETs was associated with changes in management and diagnosis of MCI and dementia.

Association between multimorbidity, self-rated health and life satisfaction among independent, community-dwelling very old persons in Japan: longitudinal cohort analysis from the Kawasaki Ageing and Well-being Project.

OBJECTIVE: This study aimed to identify associations between multimorbidity and subjective health outcomes among the very old persons, after adjusting for coexisting conditions such as frailty and depression. STUDY SETTING AND PARTICIPANTS: This was an observational cross-sectional study involving 1012 independent, community-dwelling very old persons (507 men, 505 women; aged 85-89 years) in Kawasaki city, Japan. OUTCOME MEASURES: The primary outcome was the cross-sectional associations between multimorbidity and poor self-rated health (SRH) and life satisfaction using binary logistic regression. The secondary outcome was the association of subjective health with each chronic condition. RESULTS: The prevalence of multimorbidity (≥2 conditions) was 94.7%, and the average number of chronic conditions was 4.47±1.9. Multimorbidity was significantly associated with poor SRH in the adjusted model only when six or more chronic conditions were present (OR 4.80; 95% CI 1.34 to 17.11; p=0.016). Cerebrovascular disease, heart disease, respiratory disease, connective tissue disease and arthritis showed significant associations with poor SRH after multivariate adjustment. Sex-specific analysis replicated associations between multimorbidity with six or more conditions and SRH in both men and women, while the diseases with the greatest impact on SRH differed between men and women. Most conditions were not associated with low satisfaction with life scale, with the exception of arthritis (OR 1.92, 95% CI 1.32 to 2.78, p=0.001). CONCLUSIONS: Multimorbidity is prevalent in the independent, community-dwelling very old persons and is associated with poor SRH when six or more conditions are present; conditions causing mobility limitations, such as cerebrovascular disease, connective tissue disease and arthritis, have a negative impact on SRH. TRIAL REGISTRATION NUMBER: UMIN000026053.

Characterization of alternative isoforms and inclusion body of the TAR DNA-binding protein-43.

TAR DNA-binding protein-43 (TDP-43) has been recently identified as a major component of the ubiquitinated inclusions found in frontotemporal lobar degeneration with ubiquitin-positive inclusions and in amyotrophic lateral sclerosis, diseases that are collectively termed TDP-43 proteinopathies. Several amyotrophic lateral sclerosis-linked mutations of the TDP-43 gene have also been identified; however, the precise molecular mechanisms underlying the neurodegeneration remain unclear. To investigate the biochemical characteristics of TDP-43, we examined truncation, isoforms, and cytoplasmic inclusion (foci) formation using TDP-43-expressing cells. Under apoptosis, caspase-3 generates two 35-kDa (p35f) and 25-kDa (p25f) fragments. However, in caspase-3(-/-) cells, novel caspase-3-independent isoforms of these two variants (p35iso and p25iso) were also detected under normal conditions. With a deletion mutant series, the critical domains for generating both isoforms were determined and applied to in vitro transcription/translation, revealing alternate in-frame translation start sites downstream of the natural initiation codon. Subcellular localization analysis indicated that p35 (p35f and p35iso) expression leads to the formation of stress granules, cellular structures that package mRNA and RNA-binding proteins during cell stress. After applying proteasome inhibitors, aggresomes, which are aggregates of misfolded proteins, were formed in the cytoplasm of cells expressing p35. Collectively, this study demonstrates that the 35-kDa isoforms of TDP-43 assemble in stress granules, suggesting that TDP-43 plays an important role in translation, stability, and metabolism of mRNA. Our findings provide new biological and pathological insight into the development of TDP-43 proteinopathies.

NEAT1 lncRNA and amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a representative neurological disease that is known to devastate entire motor neurons within a period of just a few years. Discoveries of the specific pathologies of relevant RNA-binding proteins, including TAR DNA-binding protein-43 (TDP-43) and fused in sarcoma/translocated in liposarcoma (FUS/TLS), and the causative genes of both familial and sporadic ALS have provided crucial information that could lead to a cure. In recent ALS research the GGGGCC-repeat expansion in the C9orf72 gene was identified as one of the most important pathological findings, suggesting the significance of both nuclear dysfunction due to dipeptide repeat proteins (DPRs) and RNA toxicity (such as pathological alterations of non-coding RNAs). In research on model animals carrying ALS-related molecules, the determination of whether a factor is protective or toxic has been controversial. Herein, we review the findings regarding NEAT1 RNA and C9orf72 GGGGCC repeats associated with ALS, from the viewpoint of conversion from the protective stage in the nucleus in early-phase ALS to late-phase induction of cell death. This review will provide insights for the development of RNA effectors as novel ALS treatments.

ALDH2 p.E504K Variation and Sex Are Major Factors Associated with Current and Quitting Alcohol Drinking in Japanese Oldest Old.

This study identified the factors associated with current and quitting alcohol drinking in the Oldest Old to better understand the associated factors and mechanisms underlying drinking behaviors in this age group. Results of a questionnaire for drinking behavior in 1015 Japanese Oldest Old citizens aged 85 to 89 years revealed that 56.0% of men and 24.0% of women were current drinkers. A genome-wide association study revealed that the rs671 G > A variation, which corresponds to the aldehyde dehydrogenase 2 (ALDH2) p.E504K missense variant, was significantly associated with current drinking (odds ratio: 3.8, p = 3.33 × 10-31). Variable selection with 41 factors and multivariate regression logistic analysis for current drinking indicated that the rs671 genotype and sex were the most significant factors in the Oldest Old. Further analysis revealed that the rs671 genotype, alcohol-associated biomarkers, a history of heart or kidney disease, and frailty score are factors associated with quitting drinking in the Oldest Old men, whereas smoking history, walking time, and depression score were factors associated with quitting drinking in the Oldest Old women. These results indicate that the ALDH2 p.E504K variation is a major factor associated with current and quitting drinking in the Japanese Oldest Old.

Novel etiological and therapeutic strategies for neurodiseases: RNA editing enzyme abnormality in sporadic amyotrophic lateral sclerosis.

The motor neurons of patients with sporadic amyotrophic lateral sclerosis (ALS) express abundant Q/R site-unedited GluR2 mRNA, whereas those of patients with other motor neuron diseases including familial ALS associated with mutated SOD1 (ALS1) and those of normal subjects express only Q/R site-edited GluR2 mRNA. Because adenosine deaminase acting on RNA type 2 (ADAR2) specifically catalyzes GluR2 Q/R site-editing, it is likely that ADAR2 activity is not sufficient to edit this site completely in motor neurons of patients with sporadic ALS. Because these molecular abnormalities occur in disease- and motor neuron-specific fashion and induce fatal epilepsy in mice, we have hypothesized that GluR2 Q/R site-underediting due to ADAR2 underactivity is a cause of neuronal death in sporadic ALS. We found that cytoplasmic fragile X mental retardation protein interacting protein 2 (CYFIP2) mRNA had an ADAR2-mediated editing position using RNA interference knockdown. Our review will include a discussion of new ADAR2 substrates that may be useful for research on sporadic ALS.

Sex-Specific Effects of Apolipoprotein ε4 Allele on Mortality in Very Old and Centenarian Japanese Men.

The apolipoprotein E4 (APOE ε4) allele has attracted attention as an age-related genetic factor, both in neurology and gerontology. To understand the effects of the APOE ε4 allele on mortality in elderly individuals, we combined Japanese prospective cohort studies comprising 535 very old individuals (85-99 years of age) and 930 centenarians (over 100 years of age) and analyzed the association between mortality rates and candidate factors, including the APOE ε4 allele. APOE genotyping revealed an inverse correlation between the APOE ε4 allele carrier rate and age. Additionally, APOE ε4 allele carrier rate in centenarian men was significantly lower than that in centenarian women. The association analysis between APOE ε4 allele carriers and all-cause mortality indicated that APOE ε4 carriers showed significantly higher mortality rates than the APOE ε4 noncarriers among men in the very old group. Further analysis using Cox proportional hazard models indicated that cause-specific mortalities, including pneumonia and severe dementia, were associated with APOE ε4 carriers. These findings indicate that the APOE ε4 allele shows phenotypic male-specific adverse effects in the very old, which would explain the high mortality rate observed in this group, resulting in a low APOE ε4 allele carrier rate in centenarian men.

HTRA1-Related Cerebral Small Vessel Disease: A Review of the Literature.

Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) is clinically characterized by early-onset dementia, stroke, spondylosis deformans, and alopecia. In CARASIL cases, brain magnetic resonance imaging reveals severe white matter hyperintensities (WMHs), lacunar infarctions, and microbleeds. CARASIL is caused by a homozygous mutation in high-temperature requirement A serine peptidase 1 (HTRA1). Recently, it was reported that several heterozygous mutations in HTRA1 also cause cerebral small vessel disease (CSVD). Although patients with heterozygous HTRA1-related CSVD (symptomatic carriers) are reported to have a milder form of CARASIL, little is known about the clinical and genetic differences between the two diseases. Given this gap in the literature, we collected clinical information on HTRA1-related CSVD from a review of the literature to help clarify the differences between symptomatic carriers and CARASIL and the features of both diseases. Forty-six symptomatic carriers and 28 patients with CARASIL were investigated. Twenty-eight mutations in symptomatic carriers and 22 mutations in CARASIL were identified. Missense mutations in symptomatic carriers are more frequently identified in the linker or loop 3 (L3)/loop D (LD) domains, which are critical sites in activating protease activity. The ages at onset of neurological symptoms/signs were significantly higher in symptomatic carriers than in CARASIL, and the frequency of characteristic extraneurological findings and confluent WMHs were significantly higher in CARASIL than in symptomatic carriers. As previously reported, heterozygous HTRA1-related CSVD has a milder clinical presentation of CARASIL. It seems that haploinsufficiency can cause CSVD among symptomatic carriers according to the several patients with heterozygous nonsense/frameshift mutations. However, the differing locations of mutations found in the two diseases indicate that distinct molecular mechanisms influence the development of CSVD in patients with HTRA1-related CSVD. These findings further support continued careful examination of the pathogenicity of mutations located outside the linker or LD/L3 domain in symptomatic carriers.

[Genetic Protective Factors for Dementia Isolated by Centenarian Researches].

Due to the recent rapid increase in the number of elderly people in the world, health management and maintenance in elderly people have become important issues. Centenaria, who are older than 100 years, tend to stay independent in their daily life with maintenance of cognitive function until the later stage of their life compared with elderly people who die earlier. In this review, we summarize the characteristics of centenarians, the genetic risk and protective factors for longevity, and intersections between research on centenarians and dementia research.

Antigenic Change in Human Influenza A(H2N2) Viruses Detected by Using Human Plasma from Aged and Younger Adult Individuals.

Human influenza A(H2N2) viruses emerged in 1957 and were replaced by A(H3N2) viruses in 1968. The antigenicity of human H2N2 viruses has been tested by using ferret antisera or mouse and human monoclonal antibodies. Here, we examined the antigenicity of human H2N2 viruses by using human plasma samples obtained from 50 aged individuals who were born between 1928 and 1933 and from 33 younger adult individuals who were born after 1962. The aged individuals possessed higher neutralization titers against H2N2 viruses isolated in 1957 and 1963 than those against H2N2 viruses isolated in 1968, whereas the younger adults who were born between 1962 and 1968 possessed higher neutralization titers against H2N2 viruses isolated in 1963 than those against other H2N2 viruses. Antigenic cartography revealed the antigenic changes that occurred in human H2N2 viruses during circulation in humans for 11 years, as detected by ferret antisera. These results show that even though aged individuals were likely exposed to more recent H2N2 viruses that are antigenically distinct from the earlier H2N2 viruses, they did not possess high neutralizing antibody titers to the more recent viruses, suggesting immunological imprinting of these individuals with the first H2N2 viruses they encountered and that this immunological imprinting lasts for over 50 years.

Determination of editors at the novel A-to-I editing positions.

A-to-I RNA editing modifies a variety of biologically important mRNAs, and is specifically catalyzed by either adenosine deaminase acting on RNA type 1 (ADAR1) or type 2 (ADAR2) in mammals including human. Recently several novel A-to-I editing sites were identified in mRNAs abundantly expressed in mammalian organs by means of computational genomic analysis, but which enzyme catalyzes these editing sites has not been determined. Using RNA interference (RNAi) knockdowns, we found that cytoplasmic fragile X mental retardation protein interacting protein 2 (CYFIP2) mRNA had an ADAR2-mediated editing position and bladder cancer associated protein (BLCAP) mRNA had an ADAR1-mediated editing position. In addition, we found that ADAR2 forms a complex with mRNAs with ADAR2-mediated editing positions including GluR2, kv1.1 and CYFIP2 mRNAs, particularly when the editing sites were edited in human cerebellum by means of immunoprecipitation (IP) method. CYFIP2 mRNA was ubiquitously expressed in human tissues with variable extents of K/E site editing. Because ADAR2 underactivity may be a causative molecular change of death of motor neurons in sporadic amyotrophic lateral sclerosis (ALS), this newly identified ADAR2-mediated editing position may become a useful tool for ALS research.

Newly identified ADAR-mediated A-to-I editing positions as a tool for ALS research.

Among the extensively occurring adenosine to inosine (A-to-I) conversions in RNA, RNA editing at the GluR2 Q/R site is crucial for the survival of mammalian organisms. Editing at this site is incomplete in the motor neurons of patients with sporadic amyotrophic lateral sclerosis (ALS). Adenosine deaminase acting on RNA type 2 (ADAR2) specifically mediates GluR2 Q/R site-editing, hence, it is likely a molecule relevant to the pathogenesis of sporadic ALS. Since no other transcript with ADAR2-mediated A-to-I positions is abundantly expressed in most neurons, the editors at the newly identified A-to-I positions were investigated. CYFIP2 and FLNA mRNAs were identified together with mRNAs having known ADAR2-mediated editing positions in ADAR2-immunoprecipitates of the human cerebellum, indicating that these mRNAs probably possessed ADAR2-mediated positions. Furthermore, an in vitro RNAi knockdown system demonstrated that the CYFIP2 mRNA K/E site and the BLCAP mRNA Y/C site were edited predominantly by ADAR2 and ADAR1, respectively. CYFIP2 mRNA was ubiquitously expressed and particularly abundant in the central nervous system. The extent of CYFIP2 K/E site-editing was between 30% and 80% in the central nervous system. Therefore, the extent of CYFIP2 K/E site-editing may be an additional marker for ADAR2 activity in neuronal and other types of cells in vivo, as well as in vitro, and thus is considered to be a good tool for sporadic ALS research.