Senescence-Associated Heterochromatin Foci Suppress γ-H2AX Focus Formation Induced by Radiation Exposure.

DNA damage is induced by both endogenous and exogenous factors. Repair of DNA double-strand break (DSB), a serious damage that threatens genome stability, decreases with senescence. However, the molecular mechanisms underlying the decline in DNA repair capacity during senescence remain unclear. We performed immunofluorescence staining for phosphorylated histone H2AX (γ-H2AX) in normal human fetal lung fibroblasts and human skin fibroblasts of different ages after chronic irradiation (total dose, 1 Gy; dose rate, 1 Gy/day) to investigate the effect of cellular senescence and organismal aging on DSB repair. Accumulation of DSBs was observed with cellular senescence and organismal aging, probably caused by delayed DSB repair. Importantly, the formation of γ-H2AX foci, an early event in DSB repair, is delayed with cellular senescence and organismal aging. These results suggest that the delay in γ-H2AX focus formation might delay the overall DSB repair. Interestingly, immediate γ-H2AX foci formation was suppressed in cells with senescence-associated heterochromatin foci (SAHF). To investigate the relationship between the γ-H2AX focus formation and SAHF, we used LiCl to relax the SAHFs, followed by irradiation. We demonstrated that LiCl rescued the delayed γ-H2AX foci formation associated with cellular senescence. This indicates that SAHF interferes with γ-H2AX focus formation and inhibits DSB repair in radiation-induced DSB. Our results suggest that therapeutic targeting of SAHFs have potential to resolve DSB repair dysfunction associated with cellular senescence.

Structural analysis of polyglycerol fatty acid ester-coenzyme Q10 aggregates in solution.

Polyglycerol fatty acid esters (PGFEs) are common food additives. PGFE-based formulations exhibit high structural stability, however, the stability mechanism of the micellar structures has not been yet elucidated. In this study, nanostructural analysis was performed using small-angle neutron and X-ray scattering (SANS and SAXS) measurements to reveal the mechanism of the structural stability of PGFE-coenzyme Q10 (CoQ10) mixtures as a CoQ10 formulation. Pure PGFE formed multilamellar vesicles, whereas PGFE-CoQ10 formed spherical micelles. Furthermore, when the amount of added water increased, the PGFE-CoQ10 micellar size and the amount of water in the micelles remained unchanged. A model-fitting analysis of the SANS results suggested that the CoQ10 molecules were introduced between the surfactants, forming a palisade-type structure. The high structural stability of the PGFE-CoQ10 micelles was attributed to two factors: proper spreading of the hydrophilic head chains and inhibition of the change of the amount of water inside the micelles by the PGFE heads and quinone ring of CoQ10. This indicates that PGFE-CoQ10 can function in water while maintaining the micellar structure formed in the storage solution. The findings of this study are important for the safety and nano-hazard aspects of PGFE-CoQ10 formulations.

Natto extract inhibits infection caused by the Aujeszky's disease virus in mice.

Aujeszky's disease virus (ADV), also known as Suid alphaherpesvirus 1, which mainly infects swine, causes life-threatening neurological disorders. This disease is a serious global risk factor for economic losses in the swine industry. The development of new anti-ADV drugs is highly anticipated and required. Natto, a traditional Japanese fermented food made from soybeans, is a well-known health food. In our previous study, we confirmed that natto has the potential to inhibit viral infections by severe acute respiratory syndrome coronavirus 2 and bovine alphaherpesvirus 1 through their putative serine protease(s). In this study, we found that an agent(s) in natto functionally impaired ADV infection in cell culture assays. In addition, ADV treated with natto extract lost viral infectivity in the mice. We conducted an HPLC gel-filtration analysis of natto extract and molecular weight markers and confirmed that Fraction No. 10 had ADV-inactivating ability. Furthermore, the antiviral activity of Fraction No. 10 was inhibited by the serine protease inhibitor 4-(2-Aminoethyl) benzene sulfonyl fluoride hydrochloride (AEBSF). These results also suggest that Fraction No. 10, adjacent to the 12.5 kDa peak of the marker in natto extract, may inactivate ADV by proteolysis. Our findings provide new avenues of research for the prevention of Aujeszky's disease.

Bone Marrow Failure and Immunodeficiency Associated with Human RAD50 Variants.

PURPOSE: The MRE11-RAD50-NBN (MRN) complex plays a key role in recognizing and signaling DNA double-strand breaks. Pathogenic variants in NBN and MRE11 give rise to the autosomal-recessive diseases, Nijmegen breakage syndrome (NBS) and ataxia telangiectasia-like disorder, respectively. The clinical consequences of pathogenic variants in RAD50 are incompletely understood. We aimed to characterize a newly identified RAD50 deficiency/NBS-like disorder (NBSLD) patient with bone marrow failure and immunodeficiency. METHODS: We report on a girl with microcephaly, mental retardation, bird-like face, short stature, bone marrow failure and B-cell immunodeficiency. We searched for candidate gene by whole-exome sequencing and analyzed the cellular phenotype of patient-derived fibroblasts using immunoblotting, radiation sensitivity assays and lentiviral complementation experiments. RESULTS: Compound heterozygosity for two variants in the RAD50 gene (p.Arg83His and p.Glu485Ter) was identified in this patient. The expression of RAD50 protein and MRN complex formation was maintained in the cells derived from this patient. DNA damage-induced activation of the ATM kinase was markedly decreased, which was restored by the expression of wild-type (WT) RAD50. Radiosensitivity appeared inconspicuous in the patient-derived cell line as assessed by colony formation assay. The RAD50R83H missense substitution did not rescue the mitotic defect in complementation experiments using RAD50-deficient fibroblasts, whereas RAD50WT did. The RAD50E485X nonsense variant was associated with in-frame skipping of exon 10 (p.Glu485_545del). CONCLUSION: These findings indicate important roles of RAD50 in human bone marrow and immune cells. RAD50 deficiency/NBSLD can manifest as a distinct inborn error of immunity characterized by bone marrow failure and B-cell immunodeficiency.

TUG1-mediated R-loop resolution at microsatellite loci as a prerequisite for cancer cell proliferation.

Oncogene-induced DNA replication stress (RS) and consequent pathogenic R-loop formation are known to impede S phase progression. Nonetheless, cancer cells continuously proliferate under such high-stressed conditions through incompletely understood mechanisms. Here, we report taurine upregulated gene 1 (TUG1) long noncoding RNA (lncRNA), which is highly expressed in many types of cancers, as an important regulator of intrinsic R-loop in cancer cells. Under RS conditions, TUG1 is rapidly upregulated via activation of the ATR-CHK1 signaling pathway, interacts with RPA and DHX9, and engages in resolving R-loops at certain loci, particularly at the CA repeat microsatellite loci. Depletion of TUG1 leads to overabundant R-loops and enhanced RS, leading to substantial inhibition of tumor growth. Our data reveal a role of TUG1 as molecule important for resolving R-loop accumulation in cancer cells and suggest targeting TUG1 as a potent therapeutic approach for cancer treatment.

The ribonuclease domain function is dispensable for SLFN11 to mediate cell fate decision during replication stress response.

The SLFN11 gene participates in cell fate decision following cancer chemotherapy and encodes the N-terminal ribonuclease (RNase) domain and the C-terminal helicase/ATPase domain. How these domains contribute to the chemotherapeutic response remains controversial. Here, we expressed SLFN11 containing mutations in two critical residues required for RNase activity in SLFN11-/- cells. We found that this mutant was still able to suppress DNA damage tolerance, destabilized the stalled replication forks, and perturbed recruitment of the fork protector RAD51. In contrast, we confirmed that the helicase domain was essential to accelerate fork degradation. The fork degradation by the RNase mutant was dependent on both DNA2 and MRE11 nuclease, but not on MRE11's novel interactor FXR1. Collectively, these results supported the view that the RNase domain function is dispensable for SLFN11 to mediate cell fate decision during replication stress response.

Increased bioavailability of diosmetin-7-glucoside-γ-cyclodextrin inclusion complex compared with diosmin in Sprague-Dawley rats.

Diosmin (DSN) is found mainly in citrus fruits, and has potent antioxidant effects. This study aimed to evaluate pharmacokinetics of diosmetin-7-glucoside-γ-cyclodextrin (DIOSG-CD) inclusion complex. The area under the curve values from AUC0-24 of DIOSG-CD, prepared by reacting DSN and naringinase with γ-CD, were approximately 800-fold higher than those of DSN following their administration in Sprague-Dawley rats.

APTX acts in DNA double-strand break repair in a manner distinct from XRCC4.

Aprataxin (APTX), the product of the causative gene for hereditary neurogenerative syndromes Ataxia-oculomotor apraxia 1 and early onset ataxia with oculomotor apraxia and hypoalbuminemia, has an enzymatic activity of removing adenosine monophosphate from DNA 5'-end, which arises from abortive ligation by DNA ligases. It is also reported that APTX physically binds to XRCC1 and XRCC4, suggesting its involvement in DNA single-strand break repair (SSBR) and DNA double-strand break repair (DSBR) via non-homologous end joining pathway. Although the involvement of APTX in SSBR in association with XRCC1 has been established, the significance of APTX in DSBR and its interaction with XRCC4 have remained unclear. Here, we generated APTX knock-out (APTX-/-) cell from human osteosarcoma U2OS through CRISPR/Cas9-mediated genome editing system. APTX-/- cells exhibited increased sensitivity toward ionizing radiation (IR) and Camptothecin in association with retarded DSBR, as shown by increased number of retained γH2AX foci. However, the number of retained 53BP1 foci in APTX-/- cell was not discernibly different from wild-type cells, in stark contrast to XRCC4-depleted cells. The recruitment of GFP-tagged APTX (GFP-APTX) to the DNA damage sites was examined by laser micro-irradiation and live-cell imaging analysis using confocal microscope. The accumulation of GFP-APTX on the laser track was attenuated by siRNA-mediated depletion of XRCC1, but not XRCC4. Moreover, the deprivation of APTX and XRCC4 displayed additive inhibitory effects on DSBR after IR exposure and end joining of GFP reporter. These findings collectively suggest that APTX acts in DSBR in a manner distinct from XRCC4.

[Antibody production capacity after COVID-19 vaccination in immune-mediated neuromuscular diseases under immunotherapy].

The post-vaccination antibody response in patients with immune-mediated neuromuscular diseases under immuno-suppressive therapy has not been sufficiently verified. The Japanese Society of Neurology has stated that coronavirus disease 2019 (COVID-19) vaccination should be given priority in patients with immunotherapy-associated neuromuscular diseases; however, data on antibody production to a novel mRNA vaccine are scarce in these patients. In this study, we aimed to measure residual antibody titers after the second dose and produced antibodies after the third dose of SARS-CoV-2 mRNA vaccine in 25 patients with neuromuscular diseases under immuno-suppressive therapy (disease group). We compared the disease group antibody titers with those of 829 healthy employees in our hospital (control group). The disease group included 17 patients with myasthenia gravis, 4 with multiple sclerosis, 3 with inflammatory muscle disease, and 1 with chronic inflammatory demyelinating polyneuropathies. Seven cases of the disease group showed negative antibody levels (<15.0 s/co) before the third vaccination, and antibody titers in the positive cases ranged from 16.9 to 4,589.0 s/co. Three of the seven antibody-negative cases turned positive after the third vaccination, and all but one of the antibody-positive cases showed a booster effect, with antibody titers after the third dose ranging from 245.1 to 85,374.0 s/co (1.0 to 885.0 times higher than those before vaccination). Although the immune response in the disease group was modest compared to the control group, in which antibody titers after the third vaccination ranged from 67.8 to 150,000 s/co (0.9 to 5,402.1 times higher than those before vaccination), the result indicated that a constant immune response was achieved under immuno-suppressive therapy. Even in the control group, three participants tested negative for residual antibody before the third inoculation, and four of the antibody-positive participants (27.7-24,054.0 s/co) lacked a booster effect after the third vaccination.

Analysis method of cellular stress caused by intermediate dose-rate irradiation using a cell lysate array technique.

Ionizing radiation damages DNA and may lead to the development of cancer. Irradiation also generates reactive oxygen species (ROS) which cause damage to various biological molecules. Relatively low dose-rate irradiation causes less damage. However, the damage and its effects on cell fate are difficult to evaluate. To develop a method to analyze the damage and accompanying changes in physiology in cells irradiated by γ-rays at a relatively low dose-rate, we used the protein array technique to quantify marker proteins involved in the stress response and the regulation of cell growth and death. This method enabled efficient analyses of many replicates of experimental data on cell lysate samples. We detected relatively small changes in the levels of these proteins in the irradiated cells. Changes in protein levels suggested ROS production and DNA damage as well as cell cycle retardation and the progression of cellular senescence. Thus, our approach shows promise for analyzing the biological effects of relatively low dose-rate irradiation.

Implication of E3 ligase RAD18 in UV-induced mutagenesis in human induced pluripotent stem cells and neuronal progenitor cells.

Pluripotent stem cells (PSCs) have the potential to differentiate to any of the other organs. The genome DNA integrity of PSCs is maintained by a high level of transcription for a number of genes involved in DNA repair, cell cycle and apoptosis. However, it remains unclear how high the frequency of genetic mutation is and how these DNA repair factors function in PSCs. In this study, we employed Sup F assay for the measurement of mutation frequency after UV-C irradiation in induced pluripotent stem cells (iPSCs) as PSC models and neural progenitor cells (NPCs) were derived from iPSCs as differentiated cells. iPSCs and NPCs exhibited a lower mutation frequency compared with the original skin fibroblasts. In RNA-seq analysis, iPSCs and NPCs showed a high expression of RAD18, which is involved in trans-lesion synthesis (TLS) for the emergency tolerance system during the replication process of DNA. Although RAD18 is involved in both error free and error prone TLS in somatic cells, it still remains unknown the function of RAD18 in PSCs. In this study we depleted of the RAD18 by siRNA knockdown resulted in decreased frequency of mutation in iPSCs and NPCs. Our results will provide information on the genome maintenance machinery in PSCs.

Mechanical Properties and Reinforcement of Paper Sheets Composited with Carboxymethyl Cellulose.

The mechanical properties for paper sheets composited with glucose (Glc), methyl cellulose (MC), and carboxymethyl cellulose (CMC) were investigated. The paper composites were prepared by immersing paper sheets in aqueous solutions of these materials and drying at 100 °C for 30 min. The stress-strain curves for these paper composites were measured by a uniaxial tensile apparatus with a stretching speed of 2 mm/min. The breaking stress and strain for untreated paper were 24 MPa and 0.016, respectively. The paper composites demonstrated stress-strain curves similar to the untreated paper; however, the breaking point largely differed for these composites. The breaking strain and breaking stress for the Glc composite slightly decreased and those for the MC composite gradually increased with the concentration of materials composited. Significant increases in the mechanical properties were observed for the CMC composite. The breaking stress, breaking strain, and breaking energy for the 3 wt.% CMC composite were 2.0-, 3.9-, and 8.0-fold higher than those for untreated paper, respectively. SEM photographs indicated that the CMC penetrated into the inner part of the paper. These results strongly suggest that the mechanical improvement for CMC composites can be understood as an enhancement of the bond strength between the paper fibrils by CMC, which acts as a bonding agent. It was also revealed that the breaking strain, breaking stress, and breaking energy for the CMC composites were at maximum at the first cycle and decreased gradually as the immersion cycles increased.

Guillain-Barré Syndrome Associated with COVID-19 in a Japanese Male.

April 2021 saw a widespread outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Osaka, Japan. We encountered the case of a 52-year-old man who had Guillain-Barré syndrome associated with coronavirus disease 2019 (COVID-19). After the relief of the respiratory symptoms owing to COVID-19, the patient experienced muscle weakness, which spread from his fingers to his extremities, and was unable to walk. Further examinations revealed mild protein elevation in the cerebrospinal fluid. In addition, nerve conduction studies showed demyelinating polyneuropathy, leading to the diagnosis of Guillain-Barré syndrome. After the administration of intravenous immunoglobulin and intravenous methylprednisolone, his symptoms drastically improved, and he was able to walk unaided 21 days after the onset of symptoms. On day 40, the patient was discharged with minimal muscle fatigue. Because Guillain-Barré syndrome associated with COVID-19 is expected to have a good prognosis, early diagnosis and treatment are important. Therefore, Guillain-Barré syndrome should be considered as a possible factor for muscle weakness during and after COVID-19 treatment.

THE ROLE OF DNA DOUBLE-STRAND BREAK REPAIR THROUGH NON-HOMOLOGOUS END JOINING IN THE DOSE-RATE EFFECT IN TERMS OF CLONOGENIC ABILITY.

It is generally and widely accepted that the biological effects of a given dose of ionizing radiation, especially those of low linear energy transfer radiations like X-ray and gamma ray, become smaller as the dose rate becomes lower. This phenomenon, known as 'dose-rate effect (DRE),' is considered due to the repair of sublethal damage during irradiation but the precise mechanisms for DRE have remained to be clarified. We recently showed that DRE in terms of clonogenic cell survival is diminished or even inversed in rodent cells lacking Ku, which is one of the essential factors in the repair of DNA double-strand breaks (DSBs) through non-homologous end joining (NHEJ). Here we review and discuss the involvement of NHEJ in DRE, which has potential implications in radiological protection and cancer therapeutics.

[Immune checkpoint inhibitor-induced anti-striational antibodies in myasthenia gravis and myositis: a case report].

A 78-year-old man was treated with ipilimumab and nivolumab for advanced renal cell carcinoma with liver and lymph node metastasis. He developed diplopia, ptosis, dysphagia, and weakness of the limbs and neck, 1 month after treatment. Serum creatine kinase (CK) levels were elevated, and neck MRI revealed inflammation of the deep trunk muscles. Although anti-acetylcholine receptor antibody was negative, the edrophonium test was positive. Anti-striational antibodies such as the anti-titin and the anti-muscular voltage-gated potassium channel (Kv 1.4) antibodies (which serve as biomarkers of immune checkpoint inhibitors associated with myasthenia gravis and myositis) were positive (anti-titin antibody titer 11.51, normal <1 index; anti-Kv 1.4 antibody titer 15.13, normal <1 index). Intravenous methylprednisolone pulse therapy (1,000 mg/day for 3 days), plasmapheresis, and oral prednisolone (PSL) (20 mg/day) administration improved the patient's neurological function and normalized the serum CK levels. The PSL dosage was tapered without any worsening of clinical signs. The antibody titers decreased but remained positive (anti-titin antibody 5.00, anti-Kv 1.4 antibody 3.83) one year after the initial evaluation. Therefore, low-dose PSL (5 mg/day) administration was continued, and the patient was in remission.

Possible relationship between mitochondrial changes and oxidative stress under low dose-rate irradiation.

Objectives: High dose-rate ionizing radiation (IR) causes severe DSB damage, as well as reactive oxygen species (ROS) accumulation and oxidative stress. However, it is unknown what biological processes are affected by low dose-rate IR; therefore, the molecular relationships between mitochondria changes and oxidative stress in human normal cells was investigated after low dose-rate IR.Methods: We compared several cellular response between high and low dose-rate irradiation using cell survival assay, ROS/RNS assay, immunofluorescence and western blot analysis.Results: Reduced DSB damage and increased levels of ROS, with subsequent oxidative stress responses, were observed in normal cells after low dose-rate IR. Low dose-rate IR caused several mitochondrial changes, including morphology mass, and mitochondrial membrane potential, suggesting that mitochondrial damage was caused. Although damaged mitochondria were removed by mitophagy to stop ROS leakage, the mitophagy-regulatory factor, PINK1, was reduced following low dose-rate IR. Although mitochondrial dynamics (fission/fusion events) are important for the proper mitophagy process, some mitochondrial fusion factors decreased following low dose-rate IR.Discussion: The dysfunction of mitophagy pathway under low dose-rate IR increased ROS and the subsequent activation of the oxidative stress response.

Diminished or inversed dose-rate effect on clonogenic ability in Ku-deficient rodent cells.

The biological effects of ionizing radiation, especially those of sparsely ionizing radiations like X-ray and γ-ray, are generally reduced as the dose rate is reduced. This phenomenon is known as 'the dose-rate effect'. The dose-rate effect is considered to be due to the repair of DNA damage during irradiation but the precise mechanisms for the dose-rate effect remain to be clarified. Ku70, Ku86 and DNA-dependent protein kinase catalytic subunit (DNA-PKcs) are thought to comprise the sensor for DNA double-strand break (DSB) repair through non-homologous end joining (NHEJ). In this study, we measured the clonogenic ability of Ku70-, Ku86- or DNA-PKcs-deficient rodent cells, in parallel with respective control cells, in response to high dose-rate (HDR) and low dose-rate (LDR) γ-ray radiation (~0.9 and ~1 mGy/min, respectively). Control cells and murine embryonic fibroblasts (MEF) from a severe combined immunodeficiency (scid) mouse, which is DNA-PKcs-deficient, showed higher cell survival after LDR irradiation than after HDR irradiation at the same dose. On the other hand, MEF from Ku70-/- mice exhibited lower clonogenic cell survival after LDR irradiation than after HDR irradiation. XR-V15B and xrs-5 cells, which are Ku86-deficient, exhibited mostly identical clonogenic cell survival after LDR and HDR irradiation. Thus, the dose-rate effect in terms of clonogenic cell survival is diminished or even inversed in Ku-deficient rodent cells. These observations indicate the involvement of Ku in the dose-rate effect.

Expression of LhFT1, the Flowering Inducer of Asiatic Hybrid Lily, in the Bulb Scales.

Asiatic hybrid lily leaves emerge from their bulbs in spring, after cold exposure in winter, and the plant then blooms in early summer. We identified four FLOWERING LOCUS T (FT)-like genes, LhFT1, LhFT4, LhFT6, and LhFT8, from an Asiatic hybrid lily. Floral bud differentiation initiated within bulbs before the emergence of leaves. LhFT genes were mainly expressed in bulb scales, and hardly in leaves, in which the FT-like genes of many plants are expressed in response to environmental signals. LhFT1 was expressed in bulb scales after vernalization and was correlated to flower bud initiation in two cultivars with different flowering behaviors. LhFT8 was upregulated in bulb scales after cold exposure and three alternative splicing variants with a nonsense codon were simultaneously expressed. LhFT6 was upregulated in bulb scales after flower initiation, whereas LhFT4 was expressed constantly in all organs. LhFT1 overexpression complemented the late-flowering phenotype of Arabidopsis ft-10, whereas that of LhFT8 did so partly. LhFT4 and LhFT6 overexpression could not complement. Yeast two-hybrid and in vitro analyses showed that the LhFT1 protein interacted with the LhFD protein. LhFT6 and LhFT8 proteins also interacted with LhFD, as observed in AlphaScreen assay. Based on these results, we revealed that LhFT1 acts as a floral activator during floral bud initiation in Asiatic hybrid lilies. However, the biological functions of LhFT4, LhFT6, and LhFT8 remain unclear.

RIF1 controls replication initiation and homologous recombination repair in a radiation dose-dependent manner.

RIF1 controls both DNA replication timing and the DNA double-strand break (DSB) repair pathway to maintain genome integrity. However, it remains unclear how RIF1 links these two processes following exposure to ionizing radiation (IR). Here, we show that inhibition of homologous recombination repair (HRR) by RIF1 occurs in a dose-dependent manner and is controlled via DNA replication. RIF1 inhibits both DNA end resection and RAD51 accumulation after exposure to high doses of IR. Contrastingly, HRR inhibition by RIF1 is antagonized by BRCA1 after a low-dose IR exposure. At high IR doses, RIF1 suppresses replication initiation by dephosphorylating MCM helicase. Notably, the dephosphorylation of MCM helicase inhibits both DNA end resection and HRR, even without RIF1. Thus, our data show the importance of active DNA replication for HRR and suggest a common suppression mechanism for DNA replication and HRR at high IR doses, both of which are controlled by RIF1.This article has an associated First Person interview with the first author of the paper.

Late-onset autosomal recessive cerebellar ataxia and neuropathy with a novel splicing mutation in the ATM gene.

Autosomal recessive cerebellar ataxias comprise many types of diseases. The most frequent autosomal recessive cerebellar ataxias are Friedreich ataxia, but other types are relatively rare. We encountered a consanguineous family with two cases of late-onset cerebellar ataxia with neuropathy. We performed whole-exome sequencing in one patient and confirmed by Sanger sequencing in other family members. Neurological examination revealed cerebellar ataxia, hand tremor, and neck dystonia, distal muscle wasting, and diminished tendon reflexes. The patients had no conjunctival telangiectasia or immunodeficiency. Blood examination revealed slightly elevated α-fetoprotein. Brain MRI demonstrated marked cerebellar atrophy and mild brainstem atrophy. The electrophysiologic study and nerve biopsy showed axonal neuropathy. Whole-exome sequencing revealed a novel homozygous missense variant (NM_000051.3: c.496G > C) in the ataxia-telangiectasia mutated gene. This homozygous variant was found in another patient, co-segregated within the family members-this variant results in aberrant splicing (skipping exon 5) on RT-PCR analysis. We identified the ataxia-telangiectasia mutated variant in an adult, late-onset autosomal recessive cerebellar ataxias family. We should consider ataxia-telangiectasia even in late-onset autosomal recessive cerebellar ataxias without telangiectasia or immunodeficiency.