An autopsy case of type A FTLD-TDP with a GRN mutation presenting with the logopenic variant of primary progressive aphasia at onset and with corticobasal syndrome subsequently.

A 68-year-old woman presented with difficulty finding words and writing characters. Neurological examination led to clinical diagnosis at onset of the logopenic variant of primary progressive aphasia accompanied with ideomotor apraxia, visuospatial agnosia on the right, and Gerstmann syndrome. Bradykinesia and rigidity on the right with shuffling gait developed after one year. Treatment with L-dopa had no effect. The patient was diagnosed with corticobasal syndrome (CBS). Brain magnetic resonance imaging revealed diffuse cortical atrophy dominantly on the left, especially in the temporal, parietal, and occipital lobes. Positron emission tomography did not reveal any significant accumulation of amyloid ß or tau protein. She died five years later. Neuropathological examination revealed diffuse cortical atrophy with severe neuronal loss and fibrous gliosis in the cortex. Neuronal cytoplasmic inclusions, short dystrophic neurites, and, most notably, neuronal intranuclear inclusions, all immunoreactive for phosphorylated TDP-43, were observed. Western blotting revealed a full length and fragments of phosphorylated TDP-43 at 45 and 23 kDa, respectively, confirming the pathological diagnosis of type A FTLD-TDP. Whole exome sequencing revealed a pathogenic mutation in GRN (c.87dupC). FTLD-TDP should be included in the differential diagnosis of CBS.

Complete nanopore repeat sequencing of SCA27B (GAA-FGF14 ataxia) in Japanese.

BACKGROUND: Although pure GAA expansion is considered pathogenic in SCA27B, non-GAA repeat motif is mostly mixed into longer repeat sequences. This study aimed to unravel the complete sequencing of FGF14 repeat expansion to elucidate its repeat motifs and pathogenicity. METHODS: We screened FGF14 repeat expansion in a Japanese cohort of 460 molecularly undiagnosed adult-onset cerebellar ataxia patients and 1022 controls, together with 92 non-Japanese controls, and performed nanopore sequencing of FGF14 repeat expansion. RESULTS: In the Japanese population, the GCA motif was predominantly observed as the non-GAA motif, whereas the GGA motif was frequently detected in non-Japanese controls. The 5'-common flanking variant was observed in all Japanese GAA repeat alleles within normal length, demonstrating its meiotic stability against repeat expansion. In both patients and controls, pure GAA repeat was up to 400 units in length, whereas non-pathogenic GAA-GCA repeat was larger, up to 900 units, but they evolved from different haplotypes, as rs534066520, located just upstream of the repeat sequence, completely discriminated them. Both (GAA)≥250 and (GAA)≥200 were enriched in patients, whereas (GAA-GCA)≥200 was similarly observed in patients and controls, suggesting the pathogenic threshold of (GAA)≥200 for cerebellar ataxia. We identified 14 patients with SCA27B (3.0%), but their single-nucleotide polymorphism genotype indicated different founder alleles between Japanese and Caucasians. The low prevalence of SCA27B in Japanese may be due to the lower allele frequency of (GAA)≥250 in the Japanese population than in Caucasians (0.15% vs 0.32%-1.26%). CONCLUSIONS: FGF14 repeat expansion has unique features of pathogenicity and allelic origin, as revealed by a single ethnic study.

Loss-of-function OGFRL1 variants identified in autosomal recessive cherubism families.

Cherubism (OMIM 118400) is a rare craniofacial disorder in children characterized by destructive jawbone expansion due to the growth of inflammatory fibrous lesions. Our previous studies have shown that gain-of-function mutations in SH3 domain-binding protein 2 (SH3BP2) are responsible for cherubism and that a knock-in mouse model for cherubism recapitulates the features of cherubism, such as increased osteoclast formation and jawbone destruction. To date, SH3BP2 is the only gene identified to be responsible for cherubism. Since not all patients clinically diagnosed with cherubism had mutations in SH3BP2, we hypothesized that there may be novel cherubism genes and that these genes may play a role in jawbone homeostasis. Here, using whole exome sequencing, we identified homozygous loss-of-function variants in the opioid growth factor receptor like 1 (OGFRL1) gene in 2 independent autosomal recessive cherubism families from Syria and India. The newly identified pathogenic homozygous variants were not reported in any variant databases, suggesting that OGFRL1 is a novel gene responsible for cherubism. Single cell analysis of mouse jawbone tissue revealed that Ogfrl1 is highly expressed in myeloid lineage cells. We generated OGFRL1 knockout mice and mice carrying the Syrian frameshift mutation to understand the in vivo role of OGFRL1. However, neither mouse model recapitulated human cherubism or the phenotypes exhibited by SH3BP2 cherubism mice under physiological and periodontitis conditions. Unlike bone marrow-derived M-CSF-dependent macrophages (BMMs) carrying the SH3BP2 cherubism mutation, BMMs lacking OGFRL1 or carrying the Syrian mutation showed no difference in TNF-ɑ mRNA induction by LPS or TNF-ɑ compared to WT BMMs. Osteoclast formation induced by RANKL was also comparable. These results suggest that the loss-of-function effects of OGFRL1 in humans differ from those in mice and highlight the fact that mice are not always an ideal model for studying rare craniofacial bone disorders.

Clinical and Pathological Features of FTDP-17 with MAPT p.K298_H299insQ Mutation.

BACKGROUND: MAPT is a causative gene in frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17), a hereditary degenerative disease with various clinical manifestations, including progressive supranuclear palsy, corticobasal syndrome, Parkinson's disease, and frontotemporal dementia. OBJECTIVES: To analyze genetically, biochemically, and pathologically multiple members of two families who exhibited various phenotypes of the disease. METHODS: Genetic analysis included linkage analysis, homozygosity haplotyping, and exome sequencing. We conducted tau protein microtubule polymerization assay, heparin-induced tau aggregation, and western blotting with brain lysate from an autopsy case. We also evaluated abnormal tau aggregation by using anti-tau antibody and PM-PBB3. RESULTS: We identified a variant, c.896_897insACA, p.K298_H299insQ, in the MAPT gene of affected patients. Similar to previous reports, most patients presented with atypical parkinsonism. Biochemical analysis revealed that the mutant tau protein had a reduced ability to polymerize microtubules and formed abnormal fibrous aggregates. Pathological study revealed frontotemporal lobe atrophy, midbrain atrophy, depigmentation of the substantia nigra, and four-repeat tau-positive inclusions in the hippocampus, brainstem, and spinal cord neurons. The inclusion bodies also stained positively with PM-PBB3. CONCLUSIONS: This study confirmed that the insACA mutation caused FTDP-17. The affected patients showed symptoms resembling Parkinson's disease initially and symptoms of progressive supranuclear palsy later. Despite the initial clinical diagnosis of frontotemporal dementia in the autopsy case, the spread of lesions could explain the process of progressive supranuclear palsy. The study of more cases in the future will help clarify the common pathogenesis of MAPT mutations or specific pathogeneses of each mutation.

The long-term effects of heated tobacco product exposure on the central nervous system in a mouse model of prodromal Alzheimer's disease.

Heated tobacco products (HTPs) have emerged as novel alternatives to conventional cigarettes (CCs), marketed by the tobacco industry as having a reduced potential for harm. Nevertheless, a significant dearth of information remains regarding the long-term effects of HTPs on the central nervous system (CNS). Here, we sought to shed light on the repercussions of prolonged exposure to HTPs on the CNS, employing a mouse model mimicking prodromal Alzheimer's disease (AD). Our study entailed subjecting App knock-in mice to 16 weeks of HTP exposure, administered 5 days per week, with serum cotinine concentration serving as confirmation of HTP exposure within this model. Histological analysis, aimed at assessing amyloid pathology, unveiled a minimal impact attributable to HTPs. However, exploration of differentially expressed genes in the cerebral cortex, using unadjusted p values, indicated an association between HTP exposure and non-inflammatory pathways, specifically linked to neurohypophyseal and neuropeptide hormone activity within the CNS. Of note, similar results have already been observed after exposure to CCs in vivo. Our study not only contributes insights into the potential non-inflammatory effects of HTPs within the context of AD pathogenesis but also underscores the significance of continued research to comprehend the full scope of their impact on the CNS.

'Raisin bread sign' feature of pontine autosomal dominant microangiopathy and leukoencephalopathy.

Pontine autosomal dominant microangiopathy and leukoencephalopathy is one of hereditary cerebral small vessel diseases caused by pathogenic variants in COL4A1 3'UTR and characterized by multiple small infarctions in the pons. We attempted to establish radiological features of this disease. We performed whole exome sequencing and Sanger sequencing in one family with undetermined familial small vessel disease, followed by clinicoradiological assessment and a postmortem examination. We subsequently investigated clinicoradiological features of patients in a juvenile cerebral vessel disease cohort and searched for radiological features similar to those found in the aforementioned family. Sanger sequencing was performed in selected cohort patients in order to detect variants in the same gene. An identical variant in the COL4A1 3'UTR was observed in two patients with familial small vessel disease and the two selected patients, thereby confirming the pontine autosomal dominant microangiopathy and leukoencephalopathy diagnosis. Furthermore, postmortem examination showed that the distribution of thickened media tunica and hyalinized vessels was different from that in lacunar infarctions. The appearance of characteristic multiple oval small infarctions in the pons, which resemble raisin bread, enable us to make a diagnosis of pontine autosomal dominant microangiopathy and leukoencephalopathy. This feature, for which we coined the name 'raisin bread sign', was also correlated to the pathological changes.

Apolipoprotein E genotype-dependent accumulation of amyloid ß in APP-knock-in mouse model of Alzheimer's disease.

Apolipoprotein E4 (APOE4), the strongest risk factor for late-onset Alzheimer's disease (AD), has been revealed to cause greater accumulation of extracellular amyloid ß (Aß) aggregates than does APOE3 in traditional transgenic mouse models of AD. However, concerns that the overexpression paradigm might have affected the phenotype remain. Amyloid precursor protein (APP)-knock-in (KI) mice, incorporating APP mutations associated with AD development, offer an alternative approach for overproducing pathogenic Aß without needing overexpression of APP. Here, we present the results of comprehensive analyses of pathological and biochemical traits in the brains of APP-KI mice harboring APP-associated familial AD mutations (APPNL-G-F/NL-G-F mice) crossed with human APOE-KI mice. Immunohistochemical and biochemical analyses revealed the APOE genotype-dependent increase in Aß pathology and glial activation, which was evident within 8 months in the mouse model. These results suggested that this mouse model may be valuable for investigating APOE pathobiology within a reasonable experimental time frame. Thus, this model can be considered in investigating the interaction between APOE and Aß in vivo, which may not be addressed appropriately by using other transgenic mouse models.

Autosomal Recessive Spinocerebellar Ataxia Type 9 With a Response to Phosphate Repletion: A Case Report.

Objective: Autosomal recessive spinocerebellar ataxia type 9 (SCAR9) has received attention due to its potential response to coenzyme Q10 (CoQ10) supplementation; however, the response has so far been limited and variable. Methods: We report a SCAR9 patient with severe hypophosphatemia who responded well to CoQ10 and phosphate repletion. Results: A 70-year-old man (the offspring of a consanguineous marriage) presented with cerebellar ataxia and intense fatigue after exercise. Whole-exome sequencing identified a novel homozygous deletion mutation (NM_020247.5:c.1218_1219del) in COQ8A. We thus diagnosed him with SCAR9. Supplementation of CoQ10 alleviated his symptoms, with the Scale for the Assessment and Rating of Ataxia (SARA) dropping from 16 to 14. During the course of the disease, he demonstrated continuous hypophosphatemia caused by renal phosphate wasting. Gait dysfunction due to weakness and eye movement was partially alleviated, and SARA dropped from 17 to 13 after phosphate repletion. Discussion: Phosphate repletion should be considered for patients with severe hypophosphatemia without any apparent subjective symptoms. In this case, phosphate repletion could have improved myopathy leading to partial improvement in the patient's symptoms. Further analyses regarding the association between COQ8A mutation and phosphate wasting are required to elucidate the detailed pathogenesis. Classification of Evidence: This provides Class IV evidence. This is a single observational study without controls.

CGG repeat expansion in LRP12 in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the degeneration of motor neurons. Although repeat expansion in C9orf72 is its most common cause, the pathogenesis of ALS isn't fully clear. In this study, we show that repeat expansion in LRP12, a causative variant of oculopharyngodistal myopathy type 1 (OPDM1), is a cause of ALS. We identify CGG repeat expansion in LRP12 in five families and two simplex individuals. These ALS individuals (LRP12-ALS) have 61-100 repeats, which contrasts with most OPDM individuals with repeat expansion in LRP12 (LRP12-OPDM), who have 100-200 repeats. Phosphorylated TDP-43 is present in the cytoplasm of iPS cell-derived motor neurons (iPSMNs) in LRP12-ALS, a finding that reproduces the pathological hallmark of ALS. RNA foci are more prominent in muscle and iPSMNs in LRP12-ALS than in LRP12-OPDM. Muscleblind-like 1 aggregates are observed only in OPDM muscle. In conclusion, CGG repeat expansions in LRP12 cause ALS and OPDM, depending on the length of the repeat. Our findings provide insight into the repeat length-dependent switching of phenotypes.

An Exploratory Trial of EPI-589 in Amyotrophic Lateral Sclerosis (EPIC-ALS): Protocol for a Multicenter, Open-Labeled, 24-Week, Single-Group Study.

BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder, with its currently approved drugs, including riluzole and edaravone, showing limited therapeutic effects. Therefore, safe and effective drugs are urgently necessary. EPI-589 is an orally available, small-molecule, novel redox-active agent characterized by highly potent protective effects against oxidative stress with high blood-brain barrier permeability. Given the apparent oxidative stress and mitochondrial dysfunction involvement in the pathogenesis of ALS, EPI-589 may hold promise as a therapeutic agent. OBJECTIVE: This protocol aims to describe the design and rationale for the EPI-589 Early Phase 2 Investigator-Initiated Clinical Trial for ALS (EPIC-ALS). METHODS: EPIC-ALS is an explorative, open-labeled, single-arm trial that evaluates the safety and tolerability of EPI-589 in patients with ALS. This trial consists of 12-week run-in, 24-week treatment, and 4-week follow-up periods. Patients will receive 500 mg of EPI-589 3 times daily over the 24-week treatment period. Clinical assessments include the mean monthly change of Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised total score. The biomarkers are selected to analyze the effect on oxidative stress and neuronal damage. The plasma biomarkers are 8-hydroxy-2'-deoxyguanosine (8-OHdG), 3-nitrotyrosine (3-NT), neurofilament light chain (NfL), phosphorylated neurofilament heavy chain (pNfH), homocysteine, and creatinine. The cerebrospinal fluid biomarkers are 8-OHdG, 3-NT, NfL, pNfH, and ornithine. The magnetic resonance biomarkers are fractional anisotropy in the corticospinal tract and N-acetylaspartate in the primary motor area. RESULTS: This trial began data collection in September 2021 and is expected to be completed in October 2023. CONCLUSIONS: This study can provide useful data to understand the characteristics of EPI-589. TRIAL REGISTRATION: Japan Primary Registries Network jRCT2061210031; tinyurl.com/2p84emu6. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/42032.

Gastrointestinal cancer occurs as extramuscular manifestation in FSHD1 patients.

Facioscapulohumeral dystrophy type1 (FSHD1) patients with a shortened D4Z4 repeat containing the DUX4 gene have a broad spectrum of clinical manifestations. In addition, high expression of DUX4 protein with an aberrant C terminus is frequently identified in B cell acute lymphoblastic leukemia. We investigated clinical manifestations in 31 FSHD1 patients and 30 non-affected individuals. Gastrointestinal cancers (gastric and colorectal cancers) increased after the age of 40 years and were more frequently observed in FSHD1 patients (n = 10) than in non-affected individuals (n = 2, p = 0.0217), though the incidence of cancers occurring in non-gastrointestinal tissues of FSHD1 patients was the same as that of non-affected individuals (p > 0.999). These comorbidities of FSHD1 patients were not associated with D4Z4 repeat number. Our results suggest that gastrointestinal cancers are among the extramuscular manifestations of adult FSHD1 patients, and do not depend on D4Z4 repeat number.

Nerve Ultrasonography for the Diagnosis and Evaluation of Neuralgic Amyotrophy.

Neuralgic amyotrophy (NA) is a peripheral nervous system disorder involving multifocal distribution. Although nerve ultrasonography has shown potential for detecting NA lesions, no established detection method exists for distal forearm NA. A 59-year-old man presented with weakness of the muscles innervated by the left posterior interosseous nerve (PIN), median nerve (MN), anterior interosseous nerve (AIN), and ulnar nerve (UN), following severe left shoulder pain. This case suggests that nerve ultrasonography can help accurately diagnose distal forearm NA.

Amyloid Beta Is Internalized via Macropinocytosis, an HSPG- and Lipid Raft-Dependent and Rac1-Mediated Process.

Intracellular amyloid ß peptide (Aß) accumulation has drawn attention in relation to the pathophysiology of Alzheimer's disease in addition to its extracellular deposition as senile plaque. Cellular uptake of extracellular Aß is one of the possible mechanisms by which intracellular Aß deposits form. Given the relevance of Aß inside cells, it is important to understand the mechanism by which it is taken up by them. In this study, we elucidated that Neuro2A and SH-SY5Y cells internalize specifically oligomerized Aß in a time- and dose-dependent manner. The depletion of plasma membrane cholesterol with methyl-ß-cyclodextrin or treatment with trypsin diminished the internalization of oAß, suggesting that the oAß uptake might be both a lipid raft-dependent and heparan sulfate proteoglycan-mediated process. Treatment with a macropinocytosis inhibitor (ethylisopropyl amiloride and wortmannin) also drastically reduced the uptake of oligomer-Aß (oAß). oAß-treated cells exhibited an increase in Rac1 activity, indicating that macropinocytosis induced by oAß is regulated by these small GTPases. These findings suggest that macropinocytosis is a major endocytic route through which oAß42 enters cells.

TDP-43 Accumulation Within Intramuscular Nerve Bundles of Patients With Amyotrophic Lateral Sclerosis.

Importance: Degeneration of neuromuscular junctions and axons is considered an important aspect of the pathomechanism of amyotrophic lateral sclerosis (ALS). However, a mechanism including the role of transactive response DNA-binding protein 43 (TDP-43) in axons has not been pathologically clarified. Objective: To identify and characterize the histopathology of peripheral axons in the skeletal muscle of patients with ALS. Design, Setting, and Participants: This study comprised 2 parts: a postmortem case-control study and a retrospective population-based cohort study with a minimum of 1 year of follow-up. Patients in the cohort study were enrolled from January 1, 2004, to September 30, 2019. The postmortem study included patients with sporadic ALS (SALS) with TDP-43 pathology and control patients with non-ALS disease. The cohort study enrolled patients without a family history of ALS or other neuromuscular disease and those not diagnosed with a muscle disease at biopsy. Patients were excluded if their clinical records were not screened after biopsy, if they were diagnosed with a muscular disease, and if they were harboring known causative genes of ALS. Data were collected between September 2019 and June 2021 and analyzed in June 2021. Exposures: Muscle biopsy or postmortem muscle tissue examination. Main Outcomes and Measures: Clinical information and muscle pathological characteristics. Results: A total of 10 patients with autopsy-confirmed SALS (mean [SD] age at death, 76.1 [8.5] years; 8 men [80%]) exhibited axonal phosphorylated TDP-43 (pTDP-43)-positive accumulations in intramuscular nerve bundles; the 12 control patients without ALS did not. Among the 114 patients in the cohort study (mean [SD] age, 62.3 [16.1] years; 76 men [67%]), 71 patients (62.3%) exhibited intramuscular nerve bundles; 43 (37.7%) did not. Among those who exhibited pTDP-43-positive intramuscular nerve bundles, 33 patients (22 men [66.7%]; mean [SD] age, 65.2 [15.6] years) were later diagnosed with ALS. The other 38 patients (26 men [68.4%]; mean [SD] age, 59.3 [18.0] years) showed no pTDP-43-positive bundles and did not develop ALS. Among those without evident nerve bundles (28 men [65.1%]; mean [SD] age, 61.3 [15.3] years), 3 were later diagnosed with ALS. Among patients with ALS in the biopsy cohort, 9 with pTDP-43-positive bundles showed only lower motor neuron symptoms at biopsy. Conclusions and Relevance: Results of this dual case-control and retrospective cohort study suggest that axonal pTDP-43 accumulations may be characteristic for patients with ALS. As such findings precede clinical fulfillment of the Gold Coast criteria, TDP-43 in nerve bundles may be a novel diagnostic biomarker for ALS.

Increased Serum Alkaline Phosphatase and Functional Outcome in Patients with Acute Ischemic Stroke Presenting a Low Ankle-Brachial Index.

AIMS: Elevated serum alkaline phosphatase (ALP) levels are associated with an increased risk of cerebrocardiovascular diseases. However, the associations of ALP with peripheral arterial disease (PAD) and outcomes in patients with acute ischemic stroke (AIS) are not well-known. METHODS: We examined the association between ALP levels and the ankle-brachial index (ABI) in 2111 consecutive patients with AIS. A poor functional outcome was defined as a modified Rankin Scale (mRS) score of 3-6 at 3 months after stroke. A low ABI was defined as a value of ≤ 0.9. RESULTS: Of the total cohort, 482 patients (22.8%) had a low ABI. ALP levels were higher in patients with a low ABI than in those without (p＜0.001). The multivariable logistic analysis revealed that quartiles of ALP levels were significantly associated with a low ABI (odds ratio [OR]: 1.20, 95% confidence interval [CI]: 1.08-1.33). Of the 1322 patients with a premorbid mRS score of 0-2, 434 patients (32.8%) had a poor outcome. The multivariable analysis revealed that elevated serum ALP levels and a low ABI were independently associated with poor stroke outcomes after adjustment for baseline characteristics (OR: 1.21, 95% CI: 1.07-1.38, and OR: 2.00, 95% CI: 1.40-2.84, respectively). CONCLUSIONS: Increased serum ALP levels are significantly associated with a low ABI. These indicators are independent prognostic factors for poor stroke outcomes at 3 months.

Knockdown of optineurin controls C2C12 myoblast differentiation via regulating myogenin and MyoD expressions.

Mutations in optineurin (OPTN) have been identified in a small proportion of sporadic and familial amyotrophic lateral sclerosis (ALS) cases. Recent evidences suggest that OPTN would be involved in not only the pathophysiological mechanisms of motor neuron death of ALS but also myofiber degeneration of sporadic inclusion body myositis. However, the detailed role of OPTN in muscle remains unclear. Initially, we showed that OPTN expression levels were significantly increased in the denervated muscles of mice, suggesting that OPTN may be involved in muscle homeostasis. To reveal the molecular role of OPTN in muscle atrophy, we used cultured C2C12 myotubes treated with tumor necrosis factor-like inducer of apoptosis (TWEAK) as an in vitro model of muscle atrophy. Our data showed that OPTN had no effect on the process of muscle atrophy in this model. On the other hand, we found that myogenic differentiation was affected by OPTN. Immunoblotting analysis showed that OPTN protein levels gradually decreased during C2C12 differentiation. Furthermore, OPTN knockdown inhibited C2C12 differentiation, accompanied by reduction of mRNA and protein expression levels of myogenin and MyoD. These findings suggested that OPTN may have a novel function in muscle homeostasis and play a role in the pathogenesis of neuromuscular diseases.

FXTAS is difficult to differentiate from neuronal intranuclear inclusion disease through skin biopsy: a case report.

BACKGROUND: Both fragile X-associated tremor/ataxia syndrome (FXTAS) and late-onset neuronal intranuclear inclusion disease (NIID) show CGG/GGC trinucleotide repeat expansions. Differentiating these diseases are difficult because of the similarity in their clinical and radiological features. It is unclear that skin biopsy can distinguish NIID from FXTAS. We performed a skin biopsy in an FXTAS case with cognitive dysfunction and peripheral neuropathy without tremor, which was initially suspected to be NIID. CASE PRESENTATION: The patient underwent neurological assessment and examinations, including laboratory tests, electrophysiologic test, imaging, skin biopsy, and genetic test. A brain MRI showed hyperintensity lesions along the corticomedullary junction on diffusion-weighted imaging (DWI) in addition to middle cerebellar peduncle sign (MCP sign). We suspected NIID from the clinical picture and the radiological findings, and performed a skin biopsy. The skin biopsy specimen showed ubiquitin- and p62-positive intranuclear inclusions, suggesting NIID. However, a genetic analysis for NIID using repeat-primed polymerase chain reaction (RP-PCR) revealed no expansion detected in the Notch 2 N-terminal like C (NOTCH2NLC) gene. We then performed genetic analysis for FXTAS using RP-PCR, which revealed a repeat CGG/GGC expansion in the FMRP translational regulator 1 (FMR1) gene. The number of repeats was 83. We finally diagnosed the patient with FXTAS rather than NIID. CONCLUSIONS: For the differential diagnosis of FXTAS and NIID, a skin biopsy alone is insufficient; instead, genetic analysis, is essential. Further investigations in additional cases based on genetic analysis are needed to elucidate the clinical and pathological differences between FXTAS and NIID.