Distinct Phenotypic and microRNA Expression in X-Linked Charcot–Marie–Tooth Correlated with a Novel Mutation in the GJB1 Gene
Bibliographic record
Abstract
We investigated genetic and clinical features in two siblings with an unreported frameshift mutation in the GJB1 gene, encoding connexin 32, to study CMTX-1 and its intrafamilial phenotypic variability. Connexin 32 is a gap junction protein that is located in paranodal regions and Schmidt–Lanterman incisures. Clinical features, family history, and genetic and microRNA information were collected. Genetic analysis determination was performed on genomic DNA from the two cases. Muscle-specific miR-206 was also investigated in serum. A muscle biopsy was conducted in one case, and EMG with conduction velocities was performed in both patients. In the first genetic analysis, no duplication of the PMP22 gene was found. A second genetic analysis of a panel of genes associated with inherited peripheral neuropathies was performed. We found a frameshift mutation in the connexin 32 (GJB1) gene, c.281_287del in hemizygosity, not previously reported, that segregated with the clinical phenotype. An X-linked hereditary sensory motor neuropathy was caused by the mutation in the connexin 32 gene. We found overexpression of miR-206 that was 4-fold up-regulated in the older brother and over 10-fold in the younger brother versus the controls; this might be correlated with a different muscle mass and regeneration. The two siblings presented differently evolving neuropathies due to environmental factors and lifestyles that caused nerve degeneration. We hypothesized that in this X-linked CMT, there is no expression of a truncated connexin 32 (Cx32) protein, with loss of function markedly reduced in the gap junction. In the peripheral nervous system (PNS), this might be mitigated by the presence of another connexin, Cx43. Such a reduction might affect not only gap junction formation but also myelination and muscle trophism, resulting in variable miR-206 expressivity.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 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".