Atypical features including acquired oculomotor apraxia in <i>C9orf72</i> -associated familial primary lateral sclerosis
Bibliographic record
Abstract
Background: The phenotypic variability of C9orf72 -associated disease is broadening, including atypical and non-motor presentations. C9orf72 -associated neurodegeneration has only rarely been associated with primary lateral sclerosis (PLS), and even more rarely with ocular motor apraxia. Objectives: Describe a family with C9orf72 mutation presenting with frontotemporal dementia (FTD) and atypical PLS phenotypes and discuss the implications regarding 1) where PLS lies on the ALS-FTD spectrum, and 2) how C9orf72 mutations influence PLS clinically. Methods: Chart review. Results: A 52-year-old male experiencing 4 months of progressive right lower leg spasticity with a family history of FTD was referred to us. Within 15 months, he was anarthric and required a powered wheelchair. He developed acquired ocular motor apraxia, consistent with supranuclear ophthalmoplegia. He later developed laryngeal dystonia which led to his death. Ten years later, his 67-year-old brother presented with 8 months of progressive spastic dysarthria, hyperreflexia, right foot drop, and right facial weakness. Genetic testing revealed heterozygous C9orf72 hexanucleotide repeat expansion. Conclusions: This family's presentation expands on sparse reports of C9orf72 -associated PLS. The proband showcases a severity of ocular motor deficits not yet reported in PLS, extending ocular motor findings in MND. These deficits also provide clinical evidence of degeneration outside the motor cortex/spinal cord in PLS. The symptomatology (laryngeal dystonia, rapid progression) clinically overlaps with ALS/FTD, suggesting PLS may lie on the ALS-FTD spectrum. The severity and atypicality of this case also support suggestions that C9orf72 mutations amplify the spectrum/severity of disease observed in TDP-43 proteinopathies.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| 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) | 0.002 | 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".