Unveiling MYH2-related myopathy: Histological-genetic insights from a case series and systematic review
Bibliographic record
Abstract
We report 13 unrelated patients and a systematic review of published cases through 30 October 2024, supplemented by HGMD Pro (2024.2) and LOVD (https://www.lovd.nl/) databases. In the case series, most patients (n = 11/13, 84.6%) exhibited clinical symptoms from early childhood to middle adulthood. The mean age of onset was 22.8 years (vs 7.73 years in literature review), likely because of absence of birth contractures, described in early reports. External ophthalmoparesis, though not a defining feature, should raise suspicion of MYH2-related myopathy in patients with a CPEO-like presentation and limb-girdle weakness. Notably, two patients presented with postural tremor of the upper limbs as their first symptom. Although rimmed vacuoles were a characteristic feature in initial reports of MYH2-related myopathy, they were absent in our case series. The most informative stain was ATPase, detecting the lack or reduction of type 2A fibres. Electron microscopy revealed additional features, such as the presence of cores associated with rods in one patient and pathological subsarcolemmal mitochondrial accumulations in 2 patients. Fifteen novel variants were identified amongst the 13 patients of this study, expanding the current genetic landscape for MYH2-related muscle diseases. The phenotypic and histological diversity observed can not be fully accounted for by genetic factors alone, suggesting the presence of additional contributing factors. This wide variability may lead to under-recognition of this disease, thus the importance of clinicians' awareness on the topic.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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 teacher head, 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".