Wszolek, Z.K.

Abstract Biallelic colony‐stimulating factor 1 receptor ( CSF1R ) variants are a major cause of early‐onset CSF1R ‐related disorder (CSF1R‐RD), although fewer than 30 cases have been reported and genotype–phenotype correlations remain unclear. The aim of this study was to characterize the clinical, radiological, and genetic features of patients with brain abnormalities, neurodegeneration, and dysosteosclerosis (BANDDOS). Six patients with biallelic CSF1R variants underwent detailed clinical, neurological, and magnetic resonance imaging evaluation. Three siblings with a homozygous p.Gly585Val variant showed marked phenotypic variability, ranging from severe childhood‐onset neurodegeneration to an asymptomatic presentation, all with white matter abnormalities. Three unrelated patients carried different biallelic CSF1R variants and presented with congenital skeletal abnormalities or early‐onset neurological disease of variable severity. These cases broaden the phenotypic spectrum of biallelic CSF1R‐RD and demonstrate that disease severity cannot be predicted solely by genotype, suggesting an important role for genetic or environmental modifiers.

Abstract Background Spinocerebellar ataxia type 3 (SCA3), the most common autosomal dominant ataxia, is driven by the accumulation of polyglutamine‐expanded (polyQ) ATXN3 proteins. While promising as biomarkers, their longitudinal trajectories across multiple biofluids remain poorly defined. Objectives To quantify polyQ ATXN3 levels in cerebrospinal fluid (CSF), plasma, and urine within a comprehensive cohort, utilizing serial measurements to map protein dynamics. Methods We employed a validated immunoassay to quantify polyQ ATXN3 in 97 symptomatic and 13 presymptomatic SCA3 patients, correlating levels with clinical features, ancestry, disease status, and longitudinal progression. Results Asian participants exhibited lower plasma but elevated urinary polyQ ATXN3 levels relative to other ancestries. While CSF levels were higher in symptomatic patients at baseline, they showed a significant longitudinal decline. Conclusions PolyQ ATXN3 is a viable multi‐biofluid biomarker. Declining CSF levels likely reflect neurodegeneration, supporting its role in tracking progression and emphasizing the need for ancestry‐based adjustment in trials. © 2026 International Parkinson and Movement Disorder Society.

ABSTRACT Colony stimulating factor‐1 receptor–related disorder (CSF1R‐RD) is a rare, autosomal dominant neurodegenerative disease caused by loss‐of‐function variants in the CSF1R gene, leading to microglial dysfunction and progressive white matter degeneration. Therapeutic strategies targeting microglial pathways, including activation of triggering receptor expressed on myeloid cells 2 (TREM2), have been proposed to compensate for impaired CSF1R signaling. Iluzanebart (VGL101), a monoclonal antibody TREM2 agonist, has shown promise in preclinical models. We report a longitudinal clinical course, neuroimaging findings, genetic analysis, and postmortem neuropathological examination of a 52‐year‐old patient with genetically confirmed CSF1R‐RD (c.2507G>A, p.Ser836Asn). The patient received iluzanebart as part of a Phase 2 clinical trial. Clinical progression, MRI changes, and histopathological features at autopsy were systematically analyzed. Despite treatment, the patient experienced progressive cognitive decline, neuropsychiatric symptoms, motor impairment, and seizures, culminating in death. Serial neuroimaging demonstrated worsening white matter degeneration and brain atrophy without evidence of therapeutic response. Neuropathological examination revealed characteristic features of CSF1R‐RD, including severe myelin loss, axonal spheroids, infiltration of Iba1‐positive cells with macrophage‐like morphology, and cortical neuronal abnormalities. There was no histological evidence of treatment‐related benefit or harm. This case represents the first clinicopathological assessment of iluzanebart in CSF1R‐RD and demonstrates no observable clinical, radiological, or neuropathological improvement. These findings highlight the challenges of targeting microglial dysfunction in advanced disease and suggest that TREM2 activation alone may be insufficient to alter disease progression.

Abstract Background Progressive supranuclear palsy (PSP) is a tauopathy for which there is limited understanding of epidemiological risk factors. Objective The objective of this study was to identify premorbid nonmedical and medical risk factors for PSP diagnosis in a large prospective population‐based cohort. Methods We performed a matched nested case–control study using the UK Biobank (UKB) cohort consisting of >500,000 adults aged 37 to 73 years. PSP diagnoses were identified from 2007 to censor date (August 2025) and matched 1:10 by age and sex to control subjects without parkinsonism or dementia diagnoses. We derived risk factors using an iterative logistic regression approach. Results There were 240 incident PSP diagnoses in the UKB. In the fully adjusted model, premorbid depression (odds ratio [OR], 3.22; 95% confidence interval [CI], 2.30–4.50; P < 0.001), delirium (OR, 6.76; 95% CI, 4.08–11.19; P < 0.001), and functional gastrointestinal disorders (OR, 1.91; 95% CI, 1.39–2.63; P < 0.001) were associated with increased risk. Heavy alcohol consumption was associated with higher risk compared with moderate consumption (OR, 1.65; 95% CI: 1.21–2.26; P = 0.0017). Body mass index (BMI) and alcohol consumption had nonlinear risk profiles. Cancer diagnosis was inversely associated with PSP (OR, 0.56; 95% CI, 0.40–0.79; P < 0.001). Depression and delirium diagnoses remained significant 5 to 10 years before diagnosis. Conclusions In this large prospective cohort, PSP was associated with premorbid lifestyle practices and neuropsychiatric diagnoses years before diagnosis. This suggests a long premotor phase and highlights opportunities for earlier diagnosis and further mechanistic investigation. The inverse association with cancer mirrors the relationship seen in other neurodegenerative conditions and may point toward shared mechanisms. © 2026 International Parkinson and Movement Disorder Society.

Objective This longitudinal study evaluated the long-term efficacy and safety of hematopoietic stem cell transplantation (HSCT) in slowing the progression of CSF1R-related disorder (CSF1R-RD).Methods Six symptomatic patients (mean follow-up, 6.6 years) were compared with six matched, untreated controls. The CSF1R Clinical Severity Score (CCSS), Montreal Cognitive Assessment, and Sundal radiological score were used for evaluation.Results Post-HSCT clinical progression slowed significantly from 14.1 to 3.7 CCSS/year, compared with 15.2 CCSS/year in the control group (p<0.01). Cognitive decline was substantially reduced (-1.5 points/year vs. -7.6 points/year), and radiological deterioration slowed (0.4 per year vs. 3.9 per year). Notably, during the observation period, all HSCT patients survived, whereas 50% of the patients in the control group died. No serious transplant-related complications were observed.Conclusion HSCT is a potent disease-modifying therapy for CSF1R-RD that drastically improves survival and slows deterioration. These findings underscore the necessity of early intervention during the symptomatic phase to maximize the preservation of quality of life for affected individuals.

Abstract Background Colony stimulating factor 1 receptor–related disorder (CSF1R‐RD) is a rare, rapidly progressive neurodegenerative disease with significant clinical heterogeneity. Apolipoprotein E (ApoE) polymorphism, known to modulate microglial function and influence neurodegeneration, may act as a genetic modifier in CSF1R‐RD. Objectives The objectives were to evaluate the distribution of ApoE alleles in CSF1R‐RD and assess their association with clinical and neuropathological features. Methods ApoE genotyping was performed in 55 individuals with CSF1R‐RD. Clinical data from 25 deceased patients were analyzed based on ApoE genotype. Neuropathological evaluation was conducted on brain tissue from 14 patients, with semiquantitative scoring of white matter pathology and microglial burden. Statistical comparisons were made between carriers and noncarriers of the ApoE4 allele. Results ApoE allele frequencies in CSF1R‐RD mirrored those of the general population (ε2: 7.3%, ε3: 79.1%, ε4: 13.6%). However, ApoE4 carriers exhibited significantly earlier symptom onset (median: 37.9 vs. 50.3 years, p = 0.0123) and death (median: 41.1 vs. 55.2 years, p = 0.0072). Neuropathological analysis revealed more severe white matter involvement and reduced microglial preservation in ApoE4 carriers ( p = 0.034). Conclusions Although ApoE allele distribution does not differ from the general population, the presence of the ApoE4 allele may influence the clinical trajectory and white matter pathology in CSF1R‐RD. These findings suggest that ApoE polymorphism is a potential modifier of disease course and should be considered in therapeutic planning and future research. © 2026 International Parkinson and Movement Disorder Society.

Objective Colony-stimulating factor-1 receptor (<i>CSF1R</i>)-related disorder (CSF1R-RD) is a rapidly progressive neurodegenerative disease with a median onset of 43 years. More than 200 <i>CSF1R</i> pathogenic variants have been identified. Patients develop rapidly progressive dementia and motor symptoms, with a median disease duration of 6.8 years. The p.R777Q variant causes CSF1R-RD; it is deleterious to protein function. We describe the clinical and pathological features of CSF1R-RD associated with p.R777Q and report a new family carrying this variant. We compare the neuropathological findings of an index patient (with short-duration disease) with those of a patient with long-duration CSF1R-RD.Methods We present clinical and imaging data from a new family with p.R777Q. We also describe the neuropathology of an index patient and contrast these findings with features of a patient with CSF1R-RD with an 11-year disease course caused by the c.2656_2657insC variant.Results We reviewed the literature on 13 individuals from 8 families with the p.R777Q variant from Asia, Europe, and North America. The mean age at onset was 41±14 years, ranging from 22 to 63 years, and the mean survival was 3.3±2.5 years. Neuropathologic studies of our index patient (10-month disease duration) revealed features consistent with CSF1R-RD. Axonal and myelin pathology was severe in the periventricular white matter. Compared with the patient with an 11-year disease duration, the index patient had less severe white matter lesions.Conclusion Compared with CSF1R-RD associated with other variants, the p.R777Q variant has an aggressive course. Compared with the patient with a long disease duration, the index patient had milder neuropathological findings. These differences may be specific to p.R777Q or associated with rapid clinical progression.

Abstract Background Dystonia and Parkinson's disease (PD) exhibit clinical and genetic overlap, but the relevance of dystonia gene variants in PD remains unclear. Objective The aim was to assess the frequency of dystonia‐linked pathogenic variants in PD. Methods We screened sequencing data from 15,684 individuals (8272 PD, 3200 atypical parkinsonism, and 4212 unaffected) from the Global Parkinson's Genetics Program (GP2) and Accelerating Medicines Partnership‐Parkinson's Disease (AMP‐PD) for variants in genes linked to isolated dystonia, dystonia‐parkinsonism, and myoclonus‐dystonia. Results Pathogenic variants were identified only in PD patients. Forty‐five PD individuals (0.54%) carried 26 distinct (likely) pathogenic variants in nine dystonia‐linked genes, most frequently in GCH1 , followed by VPS16 . Conclusion Though rare, pathogenic variants in dystonia‐linked genes are present in clinically and pathologically diagnosed PD. Our results reinforce GCH1 as a PD‐relevant gene with clinical implications, whereas variants identified in other genes are rare and of uncertain relation to the PD phenotype. © 2025 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.