Intranuclear inclusions in neural cells with premutation alleles in fragile X associated tremor/ataxia syndrome
Bibliographic record
Abstract
Fragile X syndrome is generally considered to be a non-progressive neurodevelopmental disorder in which carriers of premutation alleles (~55 to 200 CGG repeats) of the fragile X mental retardation 1 (FMR1) gene are largely unaffected. However, we have recently identified a new syndrome among male carriers, characterised by tremor and/or ataxia, cognitive deficits, parkinsonism, and autonomic dysfunction.1,5,6,8,10 Neuroradiological findings include moderate to severe cortical atrophy (cerebral and cerebellar cortical volume loss) and characteristic hyperintensities on T2-weighted MR imaging of the deep cerebellar white matter and middle cerebellar peduncles.2,8 The disorder, termed fragile X associated tremor/ataxia syndrome,8 has been observed thus far almost exclusively in older adult male premutation carriers of more than 50 years of age. Eosinophilic intranuclear inclusions are broadly distributed in both neurones and astrocytes throughout the cerebrum and brain stem of all persons with fragile X associated tremor/ataxia syndrome (FXTAS) examined to date (8/8),5,7 with the greatest numbers of neuronal inclusions found in the hippocampus. No inclusions were detected in the Purkinje cells, although axonal degeneration and Purkinje cell loss were prominent findings in the cerebellum.5 Premutation carriers generally have elevated FMR1 mRNA levels, suggesting that FXTAS could result from a toxic gain of function of the FMR1 mRNA.5,6,8 To determine whether inclusion formation and clinical involvement are associated with allelic mosaicism, we defined the size of the CGG expansion and the relative expression levels of the FMR1 gene in various regions of the brain of a male premutation carrier who died with neurological symptoms consistent with FXTAS, and whose neural cells possessed numerous intranuclear inclusions. Analysis of multiple brain regions was undertaken to demonstrate that premutation alleles were directly associated with inclusion formation, and that full mutation alleles, even if present at …
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".